/ 
 
 Class J^ . ^ 
 Book «Ca B3_ 
 
 Gop}TightN".. 
 
 COP^'RlGliT DEPOSIT 
 
Introduction 
 
 TO THE 
 
 SOILS of CALIFORNIA 
 
 BY 
 
 GILBERT ELLIS BAILEY 
 
 Head of the Department of Geology, University of 
 
 Southern California, Los Angeles, 
 
 California 
 
 Los Angeles, Cal. 
 
 WESTERN EMPIRE PUBLISHING CO.. 
 
 1913 
 
Copyright 1913 
 
 by 
 
 Gilbert Ellis Bailey 
 
 All rights reserved 
 
 >^xrv^ 
 
 
 ■WOODS." Inc , Printers and Eneraver* 
 Lot Angele*. Cal. 
 
 OCU357485 
 
FOREWORD 
 
 A preface should not be an apology for spreading printers' 
 ink on paper. It should be a statement of the author's pur- 
 pose ; something to give the work more force, and enable it 
 to do the good it was planned to do; something to place the 
 reader in closer touch mentally with the writer. 
 
 The soil is the principal asset of the nation. It provides 
 the raw material for upward of sixty per cent of the gross 
 value of all the products of manufacture, and the railroads 
 and steamers with a large part of their tonnage. It supplies 
 the population of the country with most of their food and 
 clothing, with much of the material for their houses and house 
 furnishing, and with part of their fuel. In spite of these facts 
 this "the greatest of assets" is neglected, abused and mis- 
 understood. This slight superficial and inconstant covering 
 of the earth should receive a measure of care which is rarely 
 devoted to it. Every owner of land needs to know something 
 of the part of the earth he is dealing with or in. The soil is 
 a precious inheritance that should be jealously guarded and 
 protected instead of being abused and neglected. It is abused 
 mainly through ignorance rather than intention, and one object of 
 the author is to help a little in removing some of this ignor- 
 ance. The soil must be understood. One needs at least some 
 definite knowledge of its physical and chemical character, its 
 hygiene, productive capacity, and adaptability to crops. 
 
 Too many look upon the soil as something essentially 
 unclean, in which seeds manage in some mysterious way to 
 grow. This attitude should be changed to admiration of the 
 beauty, harmony, and order of the mechanism of the soils, 
 on which the existence of all living beings depend ; to the 
 vast array of forces involved ; to the perfect order of their 
 action ; and to the design, purpose and intention shown in 
 their construction. Long familiarity has placed over the soil 
 the veil of the commonplace and hidden the dignified meaning 
 that exists in its structure. Men look at the soil without 
 seeing, and walk over it without thinking. They forget that 
 the solid and substantial wealth of our nation comes from the 
 
4 Soils of California 
 
 country and not from the city, and that this hard-earned 
 wealth should be used largely to improve the country and its 
 institutions. We must never in any of our philosophies get 
 away from the land. One object of the author is to show 
 that the commercial value and relation to crops can be seen 
 in the field from the physical character of the soil. 
 
 The grouping by classes, such as the loams, sandy loams, 
 silt loams, etc., brings out best the uses to which the soils 
 are adapted, and calls attention to the similarity of soils and 
 to the possibilities of the extension of industries into new 
 localities, climate and economic conditions permitting. The 
 time has passed for trying to plant round pegs in square 
 holes; for using a thousand acres of citrus land for raising 
 two hundred pigs; for using lima bean and sugar beet land 
 for Texas steers; or for raising chickens and Belgian hares 
 on choice date land. The cry of common sense is "intensive 
 farming," "a little land well tilled, and an ample purse well 
 filled." .';^pm 
 
 The new agriculture is advancing on the Pacific Coast 
 with strides that attract the attention of the world, and one 
 object of this work is to make accessible information that is 
 scattered through a great number of government and indi- 
 vidual reports that are not accessible to most people, and to 
 arouse an interest that will lead the tillers of the soil to study 
 and investigate for themselves, and to point out the way. 
 
 The soil and its problems offer a field of study of the 
 highest importance not only to the development of the welfare 
 of the human race, but to obtaining personal financial returns. 
 This introduction to our soils is an attempt to place in read- 
 able form some of the results of scientific thought and dis- 
 covery, and to prove that a minute study of the soil is worth 
 while. The educational value of any book or subject lies not 
 so much in the actual information presented as in its arrange- 
 ment into systematic treatment so as to develop a philosophy 
 of the subject. Schools will not make farmers or house- 
 keepers but they can stimulate an interest in youth in the 
 problems connected with these two important vocations and 
 develop clear thinking, sound argument, constructive imag- 
 ination and effective application. 
 
 The attempt has been made to be practical rather than 
 
FOBEWOBD 6 
 
 scholarly, direct and simple instead of technical, and of service 
 to every man who owns an acre or is getting a living from 
 the soil rather than for the class room or library. An effort 
 has been made to avoid unnecessary technical words and terms 
 so far as this can be done without dodging or shying at 
 unfamiliar words necessary to embody new ideas. The inde- 
 pendent farmer wants to know the whys and wherefores, and 
 he wants a simple statement of observed fact and the most 
 positive proof of the correctness of such statement; therefore, 
 only the facts have been compiled, and the reader referred 
 to special works for the theories. 
 
 Nothing original is claimed, but all sources of data have 
 been freely used and obligation to a large number of author- 
 ities is hereby given and acknowledged. I desire especially to 
 acknowledge the assistance given by Mr. E. E. Free, of the 
 U. S. Bureau of Soils; Mr. M. V. Hartranft, of the Western 
 Empire and Fruit World ; and Hon. Wm. E. Smythe, whose 
 life has been given to making each individual do his duty to an 
 acre, and each acre do its duty to the individual and to the world. 
 
 As to mistakes, if you point them out they will be cor- 
 rected next time; but the farmer or writer who hesitates for 
 fear of mistakes will never accomplish anything. As to 
 critics, — remember the words of the scientist: "Animated 
 beings who inhabit vitrified tenements ought not to project 
 lapidary fragments." 
 
 Los Angeles, 1913. 
 
University of Southern California 
 los angeles 
 
PART I 
 
 CHAPTER I 
 
 AGRICULTURAL GEOLOGY 
 
 THE SOIL is the one indestructible, immutable asset that 
 our nation possesses. It is the one resource that cannot be 
 exhausted, that cannot be used up, but if properly cared for, not 
 only clothes and feeds us but improves with age and proper 
 treatment for the continued use of posterity. 
 
 It forms the basis of our industrial wealth and a large por- 
 tion of our foreign exports, yet we are taking up the last of our 
 public lands while the country is so sparsely settled that less 
 than one-fourth of the land nominally in farms is actually under 
 cultivation. From these lands we obtain from only one-third to 
 one-half the yield per acre obtained on the older soils of Europe. 
 
 It is dependent upon us to study the soil, to understand its 
 origin, composition, properties, functions, and relations to crops, 
 to understand the changes brought about by cultivation and crop- 
 ping, to win from the soil not only for our present needs, but to 
 increase the yields for the larger population that follows. 
 
 The problems are many and some are complex. The weight 
 of an acre of soil one foot deep is about 2000 tons. The art of 
 soil management is to so manipulate and handle this 4,000,000 
 pounds of raw material at a cost of ten or twelve dollars an 
 acre as to produce the greatest quantity of profits, and still leave 
 the soil unimpaired for future generations. 
 
 The more a man knows of the nature of the soil the better 
 prepared he is to handle it properly. 
 
 AGRICULTURAL GEOLOGY. Since all soil materials 
 form a part of the structure of the earth, their origin, character, 
 and classification constitute a part of the field of geology. Agri- 
 cultural geology is a history of the outer mantle of the earth, its 
 materials, origin, character, uses and value. 
 
 The soils of California come from a great variety of geologic 
 formations. Almost the entire geologic column from the Cam- 
 brian to the latest Quaternary is represented. The rocks of each 
 
8 Soils of California 
 
 of these formations has weathered into soil somewhere in the 
 state, giving the student exceptional opportunities for study. 
 Over 200 soil types have so far been recognized by the United 
 States Department of Agriculture and mapped in California. The 
 crops produced range from the wheat, corn and barley of 
 the colder climates to the rice and cotton of the South ; from 
 apples, peaches, and pears to oranges and lemons ; from hops to 
 wine and raisin grapes ; from pine forests to date palms ; from 
 blackberries to alligator pears. The soils themselves range from 
 those at the feet of living glaciers to those in the midst of deserts ; 
 from meadows 12,000 feet above sea level to burning sands below 
 sea level. No other state in the Union presents such a variety 
 of soils or of products, or offers such an opportunity for invest- 
 tigation. 
 
 THE EARTH is one of the organisms of the Universe in 
 which all parts work together harmoniously according to plan, 
 intention, and design, as much as those of an animal or plant. It 
 was born, will reach maturity, pass through old age, and finally 
 die (that is, change form) only to renew its existence in another 
 form. The earth is not therefore in any of its parts to be con- 
 sidered as a dead, inanimate thing, but like a tree it is most active 
 on the outside. The mantle of the earth, or soil, is not a change- 
 less, lifeless, inanimate thing, but is ever moving and changing, 
 and teems with life and activity . 
 
 The relation of the earth to the sun determines the amount 
 of heat the soil receives, and gives us the seasons. The forms of 
 the earth's surface determine the angle at which the parallel rays 
 of the sun strike the different portions of the mountains, hillsides 
 and plains, and the amount of heat per square mile, giving tem- 
 peratures that range from frigid to torrid. The inclination of the 
 earth axis combined with its daily and yearly motions determines 
 the seasons at the various latitudes. The annual revolution 
 around the sun gives a succession of seasons, warm, cold, wet or 
 dry, establishing the principle of rotation, or alternating periods 
 of rest and activity for the soils. The daily rotation of the earth 
 on its axis gives alternations of light and darkness, heat and cold ; 
 giving soils, plants and animals short and frequent periods of 
 activity and rest. The structure of the earth, like the structure 
 of a plant or animal, includes solids, liquids and gases. 
 
 THE SUN, as large as 300,000 earths, furnishes by wireless 
 
Ageiciiltueal Geology 9 
 
 the light, heat, chemical and electrical rays which keep things 
 moving and active upon the surface of the earth. It is clearly 
 these forces from the sun that cause all the movements of animal 
 and vegetable life, and all the growths of roots and stems, the 
 germination of seed, the opening of the bud, and the ripening of 
 the fruit. 
 
 THE ATMOSPHERE is an intimate mixture of all sub- 
 stances that cannot take a liquid or solid state at the temperatures 
 and pressures that prevail at the earth's surface. It contains 
 79 parts of nitrogen, 21 parts of oxygen, .03 parts of carbonic 
 dioxide, and small quantities of argon and other rare elements. 
 The water vapor contents vary from time to time and from place 
 to place, as do the gases that come from volcanoes, cities and 
 manufactories, and a great variety of volatile organic substances. 
 Dust and other forms of solid matter are often suspended in the 
 atmosphere as impurities. It is mobile and active and has great 
 direct and indirect effect upon water, rocks and soils. It is a 
 thermal blanket distributing and equalizing temperatures, and 
 sustaining and promoting life. 
 
 THE HYDROSPHERE. The water which lies upon the 
 surface of the earth would form a universal ocean a little less 
 than two miles deep if the earth was a perfectly smooth sphere. 
 It occupies 72 per cent of the earth's surface and is apparently the 
 greatest of all geologic agents, constantly changing the forms of 
 land surfaces and the temperature. It is destructive and con- 
 structive, ever tearing down and building up. The historical 
 records of geology are largely due to the fact that the waters 
 have buried in systematic order relics of the life of successive 
 ages past. 
 
 THE LITHOSPHERE. The ground upon which we stand 
 is a part of the outer crust of the lithosphere or rock sphere of 
 the earth. It is composed of loose, incoherent material commonly 
 called earth or soil, and consists of clay, sand, gravel, pebbles, 
 and boulders, or mixtures of these. The great lithosphere or 
 rock globe is an oblate spheroid with a polar diameter of 7,899 
 miles and an equatorial diameter 26.8 miles more. Its surface 
 area is 196,040,700 square miles, of which only 55,153,500 square 
 miles are land, and only a small portion of this is soil capable of 
 cultivation and supporting human life. 
 
 The atmosphere and hydrosphere are mantles rather than 
 
10 Soils of Califobnia 
 
 true spheres, and both penetrate the lithosphere to some extent. 
 In order to understand the origin of soils, their properties and 
 value, one must know the character of the lithosphere and the 
 action of the atmosphere and hydrosphere upon it. 
 
 THE FACTORS. The character of the soil of any region 
 depends upon two great groups of factors: (1) The character 
 of the material from which is has been derived; (2) the processes 
 by means of which this material has been converted into a soil 
 capable of supporting plant growth. 
 
 The first has to do with soil-forming materials which are 
 part of the lithosphere, and the second with soil-forming processes 
 which are largely the action and reaction of the atmosphere and 
 hydrosphere upon the lithosphere. 
 
 The two factors are intimately associated, and any given soil 
 is always the resultant of a definite combination of these soil- 
 forming factors. Uniformity in the factors gives uniformity in 
 the soils, giving definite soil types ; while any variation in the 
 factors gives a change in character amounting to a phase or sub- 
 type of soil. A knowledge of these factors is therefore essential 
 to a proper understanding of the soils of any region. 
 
CHAPTER II 
 SOIL FORMING MATERIALS 
 
 ROCKS. The rocks at the surface of the earth are all frag- 
 ments of still older rocks of former geologic periods, broken up 
 and more or less decomposed, and form a sheet of loose frag- 
 mentary material that is called mantle rock because it overlies 
 and covers the compact, coherent mass below that cannot be easily 
 broken up or removed and is known as bedrock. 
 
 Where the bedrock projects through the soil, as on a hillside 
 or along the banks of a creek, it is called an outcrop. If the 
 bedrock lies in distinct sheets or layers, called strata, it is said 
 to be stratified. 
 
 The common kinds of stratified rocks like shale, sandstone, 
 and limestone, are also called aqueous or sedimentary rocks 
 because they were formed in water on ocean bottoms, or lakes, as 
 sediments that in time became hardened (indurated) into rock. 
 A rock may contain material of one kind only, as limestone, or it 
 may contain material of several kinds as in the case of granite. 
 It may be loose or unconsolidated like sand, or it may be solid 
 (consolidated) like sandstone. 
 
 It is desirable to know not only the kind of rocks from which 
 the soil is formed but also in what physical form these compounds 
 exist. Examine a rock with a magnifying glass, or place thin 
 sections under a microscope, and it is seen that all rocks are com- 
 posed of particles of different sizes and shapes and kind, which 
 are sometimes held together weakly .and sometimes firmly. These 
 particles are called minerals; for example, we say that the rock 
 granite is composed of the minerals mica, quartz, and feldspar. 
 
 Rocks are classified according to their chief mineral con- 
 stituent. Rocks composed largely of lime are said to be calca- 
 reous; of quartz, siliceous; of iron, ferruginous; and of clay, 
 argillaceous. If eruptive rocks contain over 60 per cent of silica 
 (quartz), they are said to be acidic; if less than 50 per cent of 
 silica, they are spoken of as basic. Rocks are often named 
 according to their structure as crystalline, such as granite and 
 marble ; vitreous or glassy, as obsidian and other volcanic rocks ; 
 
12 Soils of California 
 
 coUodial or amorphous in structure, as siliceous sinters and flint 
 nodules ; or as fragmcntal when composed wholly of the frag- 
 ments of pre-existing rocks held together by clays or cementing 
 material. Where rocks Have been forced up through fissures 
 penetrating other rocks, they are said to be intrusive. Rocks 
 formed by heat, as the lavas, are called igneous. If igneous or 
 sedimentary rocks have been radically altered in appearance or 
 character, especially one that has been rendered crystalline by 
 heat or pressure, it is called metamorphic. 
 
 Adobe is classified as a rock when considering the thick 
 clayey accumulations in the basins and plains of the arid region. 
 It is a fine clayey or silty deposit formed by the gentle wash from 
 slopes that lodges on the flats below. Clay, considered as a rock, 
 is a term commonly applied to any soft, unctuous, adhesive de- 
 posits composed largely of aluminum silicates. Many so-called 
 clays are chiefly siliceous silts or loams and not true clays. Note 
 the definition of clay in soil anaylsis. Conglomerate, often called 
 puddingstone, is a rock composed of rounded pebbles, or of 
 unconsolidated gravel. Drift, in common American usage, is a 
 mixture of clay, sand, gravel and boulders formed by the action 
 of glacial agencies. Eolian rocks are deposits formed by wind, 
 embracing especially sand dunes and much of the loess. Gneiss, 
 a foliated granite and often called stratified granite, consists 
 normally of quartz, mica, and feldspar. Granite is a granular 
 crystalline aggregate of quartz, mica, and feldspar. It is pop- 
 ularly, and properly, used for any distinctly granular and crys- 
 talline rock. Granite and gneiss crumble first into barren gravel, 
 then the quartz crumbles into sand, and the mica and feldspars 
 decay into clays. Greenstone is a comprehensive term used to 
 designate igneous and metamorphic crystalline rocks of greenish 
 hue and of intricate and minute crystallization. It is a convenient 
 field term where the mineral constituents cannot be readily deter- 
 mined. They are usually, in California, dolerites, diabases, or 
 diorites. Igneous, or fire-formed rocks, diflfer widely in composi- 
 tion and texture, and therefore weather into a great variety of 
 soils, some of which are poor, and some of which are exception- 
 ally fertile. Lava is a molten rock of variable composition com- 
 ing from vents or fissures and solidifying at the surface. They 
 vary in fertility according to their composition. Limestone is a 
 rock composed primarily of calcium carbonate, but is called 
 dolomite if it also contain considerable carbonate of magnesia. 
 
Soil Fobminq Matebial 13 
 
 Marble is pure crystallized limestone, or metamorphozed lime- 
 stone. Loess is a very fine porous siliceous silt containing some 
 calcium material which often collects in nodules. It is charac- 
 terized by its standing in vertical walls and weathering so slowly 
 that letters cut into it remain distinct for years. Its origin is still 
 a matter of controversy among geologists, being held by some as 
 purely eolian, by others as fluvial (stream) or lacustrine (lake) 
 formation, and by many more as partially eolian and partially 
 aqueous. Mantle rock or regolith is the earthy mantle that covers 
 the indurated rocks, and consists chiefly of residuary earths, soil, 
 and subsoil. Marl is an earth formed largely of calcium carbon- 
 ate, usually derived from the disintegration of shells, or from 
 the calcareous secretions of plants. The term is also applied to 
 glauconitic and other fertilizing earths. Ooze is a soft deposit 
 of the deep seas, and is characterized mainly by shells of micro- 
 scopic size. Sandstone, or indurated sand, consists of grains of 
 quartz, or grains of the various hard silicates. Quartsite is meta- 
 morphosed or crystalline sandstone generally. Shale is a more 
 or less laminated rock consisting of indurated muds, silts, or clays. 
 They are often the hardened soils of former geologic times that 
 weather into silts and clays and make good soils if not too com- 
 pact. Slate is a clay rock finely laminated and fissile, and can be 
 split into thin sheets like common roofing slate. It is apt to 
 weather into clay soils that are heavy and compact. Till is a 
 stony or bouldery clay, or rock rubbish formed by glacial action. 
 Tuff, or tufa, embraces the ashes, cinders, etc., of volcanic erup- 
 tions. Calcareous tufas embrace also the granular and cellular 
 deposits of springs, such as those of the Mono Lake district. 
 
 MINERALS. Of all the hundreds of minerals named and 
 classified, less than fifty are important geologically or commer- 
 cially, and only about a dozen of them are used in forming the 
 common rocks from which the soils are derived. Quartz is 
 familiar to all as the chief constituent of sand. It is composed 
 of 46.7 per cent of silicon and 53.5 of oxygen. It occurs in most 
 rocks as grains without definite shape. It will scratch glass and 
 cannot be scratched by a knife. When rocks decompose, the 
 minerals are broken up and the elements enter into new combina- 
 tions, but the quartz remains unaltered and is washed away or 
 blown away, forming sand, sandstones, siliceous rocks, quartzites 
 and cherts. It is an ingredient of all soils, giving them lightness, 
 
14 Soils of California 
 
 drainage, and promoting aeration. Feldspars — There are sev- 
 eral kinds of feldspars, composed of silica and aluminum, together 
 with potassium, calcium, and sodium. In the orthoclase or potash 
 feldspars, potassium is the distinguishing element, from 6 to 16 
 per cent being present. Feldspar is not quite so hard as quartz, 
 and is not readily scratched by the knife. The faces of the 
 crystals are fiat and glistening, distinguishing it from the quartz. 
 The color is variable, from flesh-colored to white, yellow, pink, or 
 red. Clays result from their rather ready decomposition. Am- 
 phibole is a type of iron-magnesium-silicate minerals, the most 
 common being hornblende, which is composed of aluminum, mag- 
 nesium, iron and calcium, which enter the soil on the weathering 
 of the mineral. Mica is a complex silicate that is easily identified 
 as it is the only common mineral that splits into very thin paper 
 like elastic leaves. The light colored potassium mica called mus- 
 covite is used under the name of isinglass or mica in stove doors 
 and lanterns. A dark colored mica containing iron, magnesium 
 and other elements is called biotite ; that containing lithia is called 
 Icpidolite, and that containing sodium, paragonitc. Lepidolite is 
 found in San Diego county as the violet colored gangue rock in 
 which the gem tourmalines are found. Mica is readily seen in 
 many soils as glistening scales, especially in soils derived from 
 granitic rocks, and such soils are said to be micaceous. Calcite is 
 calcium carbonate containing 56 per cent of lime and 44 per cent 
 of carbon dioxide. It is the principal constituent of limestone 
 and is easily scratched with a knife and effervesces with an acid, 
 distinguishing it from feldspar. Lime is not only a necessary 
 plant food but also influences in a marked degree the physical 
 condition of the soil, and the process of nitrification. It makes 
 stifif clay soil more porous, more easily pulverized, and therefore 
 more productive. It corrects the sourness or acidity of soils and 
 forms an essential ingredient of all plants. Gypsum is the hy- 
 drous sulphate of calcium, 32.5 per cent of lime, 46.6 of sulphur 
 trioxide, and 20.9 per cent of water. It is a white mineral, much 
 softer than calcite, being readily cut with a knife. It does not 
 effervesce with acids as calcite does. When calcined and ground 
 it is the common plaster-of-paris of everyday use. It reacts 
 with carbonate of soda (black alkali), forming sulphate of soda 
 and carbonate of lime and is used therefore as a corrective on 
 certain alkali soils. When not calcined but simply ground it is 
 known as land plaster and used as a fertilizer. Kaolin is the 
 
Soil Forming Material 15 
 
 hydrous silicate of aluminum, containing 46.5 per cent of silica, 
 39.5 of alumina, and 14 per cent of water. It forms the basis 
 of clay and is very soft and earthy. It is derived largely from 
 the decomposition of feldspar and is colored generally by iron or 
 other impurities. Pure white kaolin, or kaolinite, is known as 
 china clay and is the basis of pottery work. Hematite is iron 
 oxide, containing 70 per cent of iron and 30 per cent of oxygen. 
 It is one of the leading iron ores, occurring in both the hard and 
 soft forms. It gives a red streak when rubbed on a surface harder 
 than the mineral. Iron from hematite is found everywhere, 
 coloring soils and rocks red, yellow and sometimes green. Apatite 
 is essentially calcium phosphate with some chlorine or fluorine 
 and about 40 per cent of phosphoric acid so necessary to all plant 
 growth. It is not common in massive form but is fairly common 
 as a mineral in certain rocks. Pyroxene is a type of a large group 
 of rocks, forming iron-magnesium minerals, and is usually a 
 magnesium-iron-calcium silicate. It is not readily identified except 
 by those familiar with mineralogy and its identification in soils 
 is of minor importance. Chlorite is a type of a somewhat import- 
 ant group of secondary minerals identified by their green color, 
 softness, smooth or unctuous feeling. They are usually alumi- 
 num-magnesium-iron silicates with water which they give up to 
 the soil under decomposition . 
 
 ELEMENTS. The minerals that form the rocks are in turn 
 composed of chemical elements. Of all the elements known to 
 the chemists only the following are important in the soils. They 
 are given in the order of their importance in making up the 
 lithosphere : 
 
 Per cent in 
 the lithosphere 
 
 Oxygen (O) 47.02 
 
 Silicon (Si) 28.06 
 
 Aluminum (Al.) 8.16 
 
 Iron (Fe) 4.64 
 
 Calcium (Ca) 3.50 
 
 Magnesium (Mg) 2.62 
 
 Sodium (Na) 2.63 
 
 Potassium (K) 2.32 
 
 Phosphorous (P) 09 
 
 Sulphur (S) 07 
 
 Chlorine (CI) trace 
 
 Nitrogen (N) trace 
 
 SILICON. The silicon (Si) never occurs in the free state 
 but always combined with oxygen (O) in the form of silica 
 (SiOj), which unites with other minerals forming silicates. 
 
16 Soils of California 
 
 PHOSPHOROUS is present in most soils to the extent of 
 five or six parts per million. It is a plant food that is necessary 
 to all vegetable growth, promoting especially the activity of bac- 
 teria, molds and fungi. In natural mineral phosphates the phos- 
 phorous is combined with lime, and as calcium phosphate is as- 
 sociated with other minerals to form rock. In artificial fertilizers 
 the phosphorous is combined with lime, iron, or aluminum. Some 
 phosphates such as bones, which are mainly phosphate of lime, 
 also contain organic matter and some nitrogen. Phosphates are 
 not easily dissolved and special agents are used to render them 
 soluble and useful as soil fertilizers. 
 
 POTASH exists in most soils in varying degrees. That 
 which is combined with humus material, or with the hydrated 
 silicates is easily set free and easily assimilated as plant food. 
 In finely divided silicates such as clay, (silicate of aluminum) 
 the potassium becomes active as a plant food in a short time, 
 while the potassium in rock debris and sandy soil may be inert 
 indefinitely. 
 
 LIME. This occurs in soils principally as calcium carbonate, 
 but it is also found combined with the organic matter as humates, 
 with sulphuric acid as sulphate (gypsum) and with silica as sili- 
 cate of lime. Calcium carbonate, or lime-stone, increases the 
 absorption power of soils, and its presence renders the phos- 
 phates, potash, and nitrogen more readily soluble. Its value 
 is not so much for plant food as for its efifect upon the physical 
 properties of the soil. It binds the particles of sandy soil together, 
 increasing its water-holding capacity. It helps to granulate clay 
 soils, and stimulates bacterial activity. It neutralizes acids and 
 renders harmless some toxic substances. It helps, under favor- 
 able moisture conditions, to humify the soil, giving it the dark 
 color so pleasing to the farmer, as it generally denotes the pres- 
 ence of humus and means fertility. 
 
 When lime is added to muddy water the solids settle to the 
 bottom in light flufify groups of floccules, and a clear liquid is 
 left above. This is called floccnlation. Mineral acids and most 
 fertilizing material also possess this property : while alkalies pre- 
 vent and break up flocculation. Soils rich in lime are well gran- 
 ulated and maintain a much better physical condition than soils 
 of the same texture which are poor in lime contents. Large 
 amounts of lime or heavy clay soils have made them much lighter. 
 
Soil Forming Material 17 
 
 MAGNESIA. This generally exists in soils in only small 
 amounts in the form of the carbonate or the silicate. It is more 
 abundant in soils that are derived from mica schists, serpentines, 
 etc. It is not a plant food and is not desirable, even exerting a 
 toxic effect upon some plants. Limestones, raw or burned, that 
 contain magnesia should not therefore be added to soils. 
 
 IRON. This element is universally distributed, existing gen- 
 erally as the anhydrous sesquioxide, or as the hydrated sequioxides 
 of the silicates. Plants assimilate iron only in small quantities 
 but it seems indispensable to their development and to the proper 
 functional activity of their assimilating powers. If present in 
 more than small quantities it is harmful for common crop plants. 
 
 SULPHUR. This is usually present in humid regions in 
 scarcely more than a trace, enough for all common crops except 
 onions, which require a fairly large amount. 
 
 CHLORINE AND ALUMINUM are absorbed and used by 
 plants, but exist naturally in soils in sufficient quantities to supply 
 all demand. 
 
 ELEMENTS FROM THE ATMOSPHERE. Ninety per 
 cent of the crop raised comes from the atmosphere and not from 
 the earth. The atmosphere provides an inexhaustible supply of 
 oxygen, hydrogen and carbon, which are the main food of plants, 
 and only ten per cent of the plant food is demanded from the 
 minerals. These minerals exist in nearly every soil in sufficient 
 quantities to supply the plants with food, and tons of minerals are 
 not needed as food, but other material may often be added to soil 
 to advantage in order to improve its physical condition. Given 
 the proper physical conditions in the soil and crops will grow 
 and find all the food they desire as a rule. Nearly all so-called 
 wornout soils are simply abused soils, and poisoned soils whose 
 physical condition only needs to be restored in order to restore 
 their productiveness. It will not do, however, to neglect the 
 mineral matter in all cases, small as it is. For example, we find 
 in bogs vegetation consisting of species that have little mineral 
 in their composition, but we do not find nutritious seeds or fruits 
 or valuable fibres or plants with other useful qualities flourishing 
 where the vegetable mold is so thick as to prevent the roots from 
 reaching the true soil beneath. There must be the admixture of 
 organic and mineral matter ,and a good soil atmosphere as well 
 as free access to the atmosphere above the soil. 
 
18 Soils of Cai.ifobnia 
 
 NITROGEN is found chiefly in the form of nitrates, and these 
 are very sohible, leaching out of the soils quickly, and cannot 
 accumulate in the soils of humid regions. In its free state nitro- 
 gen is not directly absorbed into the tissues of growing plants, but 
 must be oxidized before it can be assimilated. It is absolutely 
 necessary to all plant life, as much so as water, and is one of the 
 most costly elements the farmer has to supply. The nitrogen of 
 the air is uncombined with oxygen and is unavailable to the plant. 
 The conservation and increase of the available nitrogen in the 
 soil is most important to the agriculturist. 
 
 Rain and snow bring down a small quantity of available nitro- 
 gen from the air, but nearly all the supply contained in the soils 
 is derived from combination (oxidation) with the nitrogen of the 
 air, or from decaying animal and vegetable matter. 
 
 It is of the greatest economic and biologic value as a plant 
 food and may be present in the soil (1) in organic compounds, 
 (2) as ammonia, (3) as nitric or nitrous acid, or (4) as amido 
 compounds. Each of these four classes may be subdivided chem- 
 ically, but that belongs to agricultural chemistry and cannot be 
 considered here. The organic nitrogen derived from the debris 
 of animal or vegetable life may be in a form easily rendered 
 available for plant food, or it may be resistant. The ammonia 
 nitrogen is a transition stage arising from decay of incomplete 
 nitrification. It may exist as gaseous ammonia or combined with 
 mineral or organic acids. The nitrogen may be present as nitrous 
 or nitric acid combined with bases, such as nitrate of lime, or ni- 
 trate of potash or soda. The amido compounds may exist in 
 varying combinations difficult to understand without a good knowl- 
 edge of agricultural chemistry. 
 
 The minute bacteria present in all soils convert the nitrogen 
 from these various sources into available nitrogen. This process 
 does not take place unless the soil is moist and has free air and 
 some base such as lime present. Nitrification cannot take place 
 unless the soil is in and is kept in the right physical condition. 
 Nitrification is most active at summer temperatures, and ceases at 
 winter temperatures. There can be no accumulation of soluble 
 nitrates in humid climates as there is in the arid and semi-arid 
 regions. Soils are unable to hold the soluble nitrates where there 
 is an excess of water. The available nitrates must pass at once 
 into growing plants, remain in store during dry periods, or be 
 
Soil Forjiing Material 19 
 
 carried away by the drainage waters from storms or irrigation. 
 Some plants, especially those of the leguminous family (beans, 
 peas, etc.) permit the development of colonies of bacteria on their 
 rootlets which have the faculty of attracting nitrogen from the 
 soil air and making it available for plant food. If it were not 
 for such agencies the stores of nitrogen would constantly decrease. 
 Agricultural biology shows that different types of soils have nitri- 
 iynng organisms of different properties, and that they may be iso- 
 lated, colonized, cultivated and transplanted. 
 
 CARBONIC DIOXIDE— CO,. This gas furnishes the car- 
 bon which is the basis of most plant structures such as wood, cellu- 
 lose, starch, sugar, etc., and is the material from which the higher 
 plants build their leaves, limbs, trunks and roots. The soil at- 
 mosphere contains more carbonic dioxide than the air above, 
 hence the soil solution is always charged with more or less 
 of the gas greatly increasing its power to dissolve minerals. Soils 
 have the power of occluding gases, and this power of absorption 
 and holding depends largely upon the physical condition of the 
 soil. Soils containing a large per cent of silt or clay absorb more 
 
 than sandy soils. 
 
 Grams Grams Grams 
 
 water ammonia CO 2 
 
 100 grams of quartz absorbs. .0.16 0.11 0.03 
 
 100 grams of clay absorbs.. 2.56 0.72 0.33 
 
 100 g-rams of humus absorbs. 16.01 18.45 2.53 
 
 The diffusion of the carbonic dioxide is dependent upon the 
 porosity of the soil, the temperature, and the moisture contents. 
 Pressing or impacting the soil, or increasing the water, is fol- 
 lowed by decrease of the diffused gas. Diffusion is also less 
 where the drainage is poor and the waters percolate slowly. The 
 percentage of organic matter in excess does not indicate the per 
 cent of carbon dioxide present. The gas may come from the 
 irrigating waters, from the air, from decaying animal or vegetable 
 matter through bacterial action, or from fertilizers. 
 
CHAPTER III 
 
 LAND FORMS 
 
 The description, classification, and correlation of land forms 
 is called geomorphology. The earth seems to be solid, stable, and 
 fixed to the last degree: yet it is really unstable and ever in mo- 
 tion, both as a whole and in all its parts. Astronomy shows that 
 the sun, moon, planets and stars are unceasing in their course. 
 Chemistry shows that the countless atoms and ions form mole- 
 cules only by a ceaseless motion that makes each particle of 
 matter, each grain of soil a little cosmos. Molecules of the ele- 
 ments make up minerals, aggregations of minerals make up rocks, 
 and rocks make up land forms. Geology shows that the earth 
 is slowly cooling and contracting and ever adjusting its parts to 
 this stress and strain. Lands emerge from the sea, and mountains 
 are lifted up only to be at once attacked and slowly destroyed 
 by atmospheric agencies. 
 
 A glance at a relief map shows that the earth is not smooth 
 but has an irregular surface of relief and depression forming hills 
 and hollows of all sizes and shapes. These are known as land 
 forms made by tearing down the rocks that make the high places, 
 and the filling up of the hollows and low places, and covering the 
 flats with soil. Each type of land form has its ow^n type of soil, 
 for similar causes give similar effects. 
 
 PLAINS, or lowlands, are broad, smooth, level, or gently 
 sloping tracts of land not far above sea level. They are generally 
 overspread with a deep layer of mantle rock brought down from 
 the higher lands by streams and winds, or produced by the decay 
 of the bedrock beneath. The term is loosely used, for tlicre are 
 hilly and rolling plains as well as level ones, high as well as low, 
 and small as well as large. 
 
 STRUCTURAL PLAINS. Most plains are underlaid by 
 undisturbed sedimentary rocks, and the flat surface conforms to 
 the flat lying rocks beneath. 
 
 COASTAL PLAINS, or former marginal sea bottoms, are 
 formed by the slow rising of the sea bottom, and are covered with 
 
Land Fobms 21 
 
 imperfectly consolidated sediments which have been washed down 
 from the older lands and deposited oflf shore. Coastal plains may 
 be recent additions to the continent and are geologically said to be 
 young; or they may be old and occuring in the interior of the con- 
 tinent far from any ocean of today. They may be peneplains, 
 the result of the filling of sea borders by wash from adjacent 
 mountains, or high lands, as the coastal plains of southern 
 California. 
 
 DEGRADED PLAINS were once high, rough regions that 
 have been worn down to flatness and low elevation by erosion, the 
 work of weather, streams, glaciers, etc. They are seldom as 
 smooth as coastal plains, but are studded with low rounded hills, 
 due to their material being harder. These are called zvorn down 
 plains or plains of degradation. 
 
 ALLUVIAL PLAINS. Large rivers in times of high water 
 spread over the adjoining country and deposit coats of sand and 
 mud, building up what are known as flood plains. The flood plain 
 formed at the mouth of a river where it drops the load of sedi- 
 ment that it has carried is called a delta, as the delta of the Colo- 
 rado River. 
 
 LAKE PLAIN. Streams in time fill up lake basins with sedi- 
 ments converting them into an almost perfectly flat lake plain or 
 lacHstritie plain. Lake Tulare is slowly evaporating and being 
 filled up and converted into a lacustrine plain. Many farms and 
 ranches in the state are being cultivated where lake waters once 
 stood. 
 
 GLACIAL PLAINS. The ice sheets that once covered the 
 Sierras melted and deposited vast sheets of mantle rock called 
 glacial drift which filled up the irregularities of the surface, form- 
 ing glacial plains or drift plains. Such plains are of minor extent 
 and importance in California but may be studied in the Sierras 
 and in the northern portion of the state. 
 
 EOLIAN PLAINS. In the arid regions, misnamed deserts, 
 the loose mantle rock is lifted, drifted, and carried away by the 
 winds, producing a zvorn-down plain studded with knobs of resist- 
 ant rock called wind-zvorn rocks, and the materials accumulate on 
 neighboring lands forming a mantle of fine sands. Both the wind- 
 worn, and the wind-filled plains are called eolian plains. 
 PLATEAUS. A plateau is relatively an elevated area of 
 
22 Soils of California 
 
 comparatively flat land. There is, however, no fixed line between 
 plains and plateaus, for in a region of low relief like the east, 
 a broad, massive, high plain at an elevation above 1000 feet may 
 be called a plateau ; while in a region of high relief like California, 
 the same name would scarcely apply to anything at an elevation 
 less than 2000 feet above sea level. Low plateaus may be called 
 uplands, and higher plateaus called highlands. They may be as 
 smooth and level as a plain, but are usually more broken, and 
 some are deeply trenched with valleys. 
 
 MOUNTAIN. A mountain is an elevation rising prominently 
 above the surrounding area. Mountain ranges are long, narrow 
 ridges of great height, caused by the upheaval of the earth's 
 crust, but their forms are due chiefly to erosion. Isolated moun- 
 tains that do not form part of a range, are either remnants left 
 by erosion, or they may be of volcanic origin. 
 
 HILLS are little mountains. In a region of low relief, hills 
 1000 feet high may be called mountains, as in Pennsylvania, but 
 in a region of high relief like California, ridges 2000 feet high 
 are often called hills ; for example, the foothills of the Sierras. 
 Hills are often due to the cutting out of the valleys between them, 
 or to the heaping up of the mantle rock, by ice sheets, winds, 
 etc. ; hence they may be hills of erosion, or hills of accuuuilation. 
 
 VALLEYS. These are the most common of relief forms. 
 Many of them have been made wholly or partially by running 
 water. Valleys that lie between mountain ranges are called inter- 
 mont valleys. Those formed by the arching down or synclinal 
 formation of the bedrock are known as structural valleys: thus 
 the Great Valley of California is both an intermont and a structual 
 valley. 
 
 BASINS are areas of deficient drainage, having no outlet to 
 the sea, hence the water must be retained until evaporated. 
 BOTTOM LANDS are built up by long continued deposition 
 of river sediments to a considerable height above the adjacent 
 lower valley plain. 
 
 BASE LEVEL. This is the plain below which erosion can- 
 not ])roceed, the final base level being sea level. There may be a 
 number of local base levels determined by the outlet of each 
 stream, but only one general base level. The base level is not a 
 topographic form but a mathematical plane which may or may 
 
Land Forms 23 
 
 not, and generally does not, coincide with a land surface. A 
 base leveled surface is any land surface, however small, which 
 has been brought approximately to a base by gradation. If the 
 area is large it is a base leveled plain. A peneplain is one which 
 has in general been reduced to a base leveled plain, but also con- 
 tains some unreduced residual areas. 
 
 BROKEN BLOCK LANDS. In some regions the earth'a 
 crust has been broken into blocks by nearly vertical cracks, very 
 much as an ice field is broken into cakes. These blocks have been 
 displaced, some upward, some downward, and others tilted on 
 one side, just as ice is tilted. The cracks are called faults. The 
 elevated block may form steep sided table lands, and if tilted 
 they form sharp crested ridges, but if depressed they may form 
 basin or rift-valleys. The Sierra Nevada is a faulted block and 
 the eastern side has been tilted up, forming a short steep slope, 
 while the west side is long and slopes at a low angle. Many cf 
 the ranges of the Great Basin are tilted blocks, and the Island 
 of San Clemente is a good example. The subsidence of a long 
 narrow block between two or more fault lines produces rift val- 
 leys such as the one commonly known as Death Valley, between 
 the Panamint and Funeral ranges, a part of its surface being be- 
 low sea level. 
 
 VOLCANIC LANDS. Volcanic eruptions produce a relief 
 of conical and dome elevations standing singly or in groups, as may 
 be seen at Mt. Shasta or at Lassen's Peak. Streams of lava flow- 
 ing from the vents have flooded thousands of square miles to a 
 great depth, building up lava plateaus with a comparatively 
 smooth surface, as in the northeast corner of the state. Volcanic 
 action is constructive more than destructive, and is a great build- 
 er of relief land forms. Lava beds weather and crumble into 
 rich soil of great agricultural importance, and volcanic dust, mis- 
 called ashes, is carried by the winds broadcast over the land, re- 
 newing the soils. Volcanic matter may be fluid, filling and chok- 
 ing original river valleys, or covering plains with a flood of mol- 
 ten rock. Good illustrations of this are common in the great 
 placer regions of the Sierras. The molten matter may be blown 
 to fragments by the escaping steam, forming showers of so- 
 called ashes which cover the earth like sand. This volcanic ash 
 is very light and the particles cohere readily, and the decay is 
 slow at first and then rapid. They are easily washed away by 
 
24 Soils of Caiifobnia 
 
 rains. While they seem to be glassy they contain considerable 
 amounts of lime, potash, soda and iron, which are added to the 
 soils. As shown elsewhere, volcanoes have added largely to the 
 agricultural wealth of this state. 
 
 ECONOMIC. Alluvial, lacustrine and glacial plains are the 
 best agricultural regions in the world on account of the depth and 
 fertility of the soils. Coastal plains come next in value, except 
 where irrigation places them in the front rank. Worndown plains 
 are often useless for agriculture on account of the shallowness of 
 the soil, but they sometimes support forests. Eolian plains are gen- 
 erally arid regions, not on account of lack of fertility in the soil, 
 for they are exceptionally fertile, but for lack of water for irri- 
 gation. Plateaus are less favorable for agriculture on account of 
 the rougher surface, poorer soil, and colder climate. The soil on 
 mountain slopes is thin and poor often, and there are large areas 
 of bare rock ; the climate may be severe, and the seasons short. 
 Agriculture is impossible high up in the mountains except in some 
 of the sheltered valleys. Mountains are the great soil factories 
 where the bedrock is rapidly broken up and carred away by the 
 streams to renew the soil in the valleys and on the plains below. 
 
PART II 
 CHAPTER IV 
 PROCESSES 
 
 In order to trace the erosion, drainage development, and 
 origin of the present land forms, and of the soil that covers them 
 we must study the processes by which these forms have been de- 
 veloped and the agencies used. This study is known as geomor- 
 phogeny. 
 
 VIRGIN SOIL. If we take up a handful of soil and examine 
 it the eye alone shows that it is made up of bits of matter, decayed 
 leaves and twigs, blackish mold and stony particles of various sizes 
 and shapes. Under the microscope we see that decay is breaking 
 up these stony particles along their edges, joints and cleavages. 
 The soil particles are ever being broken up into still finer states 
 of division. Mountains are destroyed, hills disappear, valleys are 
 filled up by agencies that seem at first to be wholly destructive. 
 The very processes that we call destructive, however, and associ- 
 ate with death, are in fact constructive and associated with life. 
 They are but changes, steps forward, not backward, which bring 
 matter from the lower mineral state up to the higher condition 
 of soil and ready to take the next upward step into plants and 
 animals, into organic living forms. 
 
 The physical properties of soils depend upon the processes 
 by which they were formed, and we must know these processes in 
 order to classify the soils, as their classification is necessarily 
 linked with their derivation. Changes in the underlying material, 
 in the rocks or subsoil below, are largely responsible for the many 
 varieties of soils known ; and the processes which gave this mate- 
 rial its present character determine the class to which the soil be- 
 longs. The factors involved in the processes vary with the climate, 
 so that soils formed under arid, semi-arid, or subhumid condi- 
 tions are always dififerent from those occuring in regions of heavy 
 rainfall. The soils in a region of low rainfall always contain a 
 larger per cent of soluble material than those of the more humid 
 regions, but lack the irrigating waters to make them available. 
 
26 Soils of California 
 
 THE ATMOSPHERE acts directly in forming soils (1) as 
 a mechanical agent, (2) as a chemical agent, (3) it furnishes 
 the conditions under which the sun produces temperature, (4) 
 it controls evaporation and precipitation. 
 
 WIND EROSION is the mechanical action of the atmosphere. 
 Rocks are worn away and converted into soil by the abrasion 
 and impact of wind-blown dust and sand. In the arid regions, 
 cliffs, hills and ranges are worn away by the sand blasts. 
 CHEMICAL WORK OF THE ATMOSPHERE. The im- 
 portant chemical changes wrought by this agency, generally in 
 connection with water, are oxidation, carbonation and hydration. 
 Iron salts are oxidized and color the soils red, and other salts are 
 slowly oxidized or converted into carbonates. Water dissolves 
 salts in the soils and the solution is drawn to the surface by 
 capillary action where the salts are left in a hydrated condition. 
 Agricultural chemistry is largely a study of the myriad forms 
 of these chemical changes. 
 
 DUST is an example of the mechanical action of the atmos- 
 phere. A feeble wind moves particles of dust, a moderate stiff 
 breeze shifts dry sand, and a very strong wind moves small peb- 
 bles. Beds of volcanic dust thirty feet deep occur in Kansas 
 and Nebraska, hundreds of miles from the nearest known vol- 
 canic vents, and the material has evidently been carried there 
 by the winds. Many of the soils of California are rich from this 
 wind-transported volcanic dust. Much of the famous loess de- 
 posits are evidently eolian. Dust forms films and layers every- 
 where, even on the bottoms of lakes, and is ever taking from or 
 bringing to the soils some material every year. 
 DUNES. The winds do not often lift sand far above the sur- 
 face of the land but move it along and raise it into mounds and 
 ridges, like drifted snow, which are known as sandnncs. These 
 dunes sometimes invade fertile lands causing great loss unless 
 checked. On the other hand this sand often does great good, 
 for blown onto clay soil and silt soil it gives them a loamy char- 
 acter and improves them. 
 
 TEMPERATURE. The daily range of the temperature is 
 influenced (1) by the latitude, '(2) by the altitude, and (3) by 
 the humidity. The lightness and dryness of the air at high alti- 
 tude allows the heat to radiate rapidly at night and the nights are 
 cool or cold. The rocks expand under the heat of the day and 
 
Pbocesses 27 
 
 contract under the cold of the night, causing the surface to crack 
 and scale off, forming heaps of debris at the feet of the cHffs. 
 The expansion and contraction of such chffs as those of the Yo- 
 semite is far greater than the uninformed would think possible. 
 
 High temperatures favor chemical action and rocks weather 
 faster in regions of abundant moisture and high temperatures. 
 The rocks of the foothills below Mt. Shasta weather much faster 
 than the rocks in the arid portions along the Colorado River, A 
 moist climate favors the growth of vegetation and its decay sup- 
 plies organic acids to increase the solvent powers of the waters ; 
 thus the rocks of the tropics are decomposed to greater depths 
 than those of the northern latitudes. A moist atmosphere favors 
 oxidation, carbonation and hydration and the greater growth of 
 vegetation, which in turn promotes rock-weathering and soil- 
 forming. 
 
 Lands sloping toward the sun are warmer than those sloping 
 away from it, as the south side of a hill is warmer than the north 
 side. Dark colored soils absorb more heat than light colored soils 
 and retain it longer. 
 
 The temperature of a soil is raised by fermentation and decay 
 of vegetation and animal matter, a fact taken advantage of by 
 those who raise mushrooms. While these factors affect the char- 
 acter of the soil, the temperature of the soil in turn affects greatly 
 its adaptability to crops. Few seed will germinate if the soil tem- 
 perature is below 45 degrees F, and from 65 to 100 degrees F is 
 more favorable. Gravelly and sandy soils are warmer than clays. 
 Wet soils are cold because much of the heat received from the 
 sun is used in evaporating the water ; hence soils are warmed by 
 draining them. 
 
 WEATHERING OF ROCKS. Bedrock exposed to the 
 weather, that is to the action of sun, air, and water, is decomposed 
 into rock waste or loose material. The oxygen of the air attacks 
 some of the rock minerals, oxydizing them, as when iron is oxi- 
 dized, or rusted, and falls into a red powder. The carbonic acid 
 gas of the air combines with lime forming carbonate of lime, 
 which is dissolved by water and carried away. Rocks expand 
 under the heat of the sun by day and contract by night, cracking, 
 peeling and scaling. Water drains into the cracks by day and 
 freezes at night in the cracks and pores, splitting the rocks. Sands 
 blown by the winds erode them, or lodge in the crevices and fur- 
 
28 Soils of California 
 
 nish a soil that plants grow in only in turn to attack the rock. 
 Roots penetrate the minutest crevices, and, growing, crack and 
 split the rocks, and the vegetable acids secreted by plants dissolve 
 the minerals. Water dissolves out caves and undermines cliffs. 
 Ice and snow shove and push rocks from their places. 
 
 The combination of these and other destructive processes is 
 called zvcathcring, and the products are sand, clay, gravel, pebbles, 
 boulders, silt and soil. 
 
 WATER plays the most important part of any single substance 
 entering into the structure of the earth. It has the widest dis- 
 tribution and is everywhere in relatively rapid motion. In the 
 gaseous form it escapes from the bosom of the ocean, from the 
 surface of the soil, from the foliage of vegetation, and from the 
 bodies of animals, to rise to varying heights above the surface 
 of the earth and to be precipitated as rain, hail or snow. It is 
 the constant evaporation of water from the sea and its return 
 to the land and the leachings of the soil that keep both the soil 
 and the water at the standard of purity which is essential to all 
 the life of the land areas. 
 
 RUN OFF. A part of the rainfall sinks below the surface 
 into drainage channels or is absorbed by the soil and rock mantle. 
 A part runs off the surface at once, and a part is evaporated. 
 The water that does not sink into the ground but flows away is 
 called the run off. The ratio of the run off to the rainfall varies 
 with the slope of the land, its relief, geologic structure, climate 
 and vegetation. The steeper the slopes, the more rapid the rain- 
 fall, the less porous the soil, and the less the vegetation, the more 
 water will run off without sinking beneath the surface. 
 
 MECHANICAL WORK OF WATER. The rain washes the 
 atmosphere, carrying down dust, smoke and gases onto the soil. 
 Some of these gases, such as the carbon dioxide (COo), dissolve 
 mineral matter in the rocks and soils. Clayey soils baked by the 
 sun are softened by the rain and are then easily removed by run- 
 ning water. The expansion and contraction caused by alternate 
 wetting and drying cause the soils on slopes to creep downward. 
 This is called soil creep. When rain falls on dry sand or dust 
 the cohesion of the particles is increased and shifting by the wind 
 is checked for a time. Drops of water fall with a certain force 
 which may seem of slight importance but which is really of great 
 
Pbocesses 29 
 
 moment. In a heavy rain, drops cut clods to pieces rapidly. A 
 flat stone may protect the soil and be left at the top of a little 
 mound of earth, or even form the top of a large pinnacle in the 
 course of time. 
 
 Rain drops have a disrupting effect that promotes the rapid 
 washing of the soils. The first efifect of erosion by water is to 
 roughen the surface by cutting valleys, and leaving ridges. The 
 final effect is to make all smooth again by leveling the ridges and 
 hills and filling up the valleys and hollows. On bare mountains 
 the heavy rains wash the soil down to lower elevations. Brush 
 and forest prevent the rain from cutting the soil to pieces and 
 from spreading in sheets and washing the soil away. 
 
 SOLVENT ACTION OF WATER. All waters, rain or 
 spring water, contain more or less mineral matter in solution. 
 Hard or soft water means that the water has much or little car- 
 bonate or sulfate of lime or of magnesia in it. This dissolved 
 mineral matter is left wherever the water evaporates. Water 
 containing carbon dioxide is a strong solvent of the carbonate and 
 phosphate of lime and of the salts of magnesia and iron. 
 
 Decaying vegetation acts upon rocks through the carbon diox- 
 ide set free. Decay of nitrogenous matter gives rise to nitric acid, 
 which dissolves mineral matter in the soil. Soils formed in the 
 arid regions where the solvent action of the water is small are 
 distinctly sandy and the particles are sharp. Soils formed under 
 subhumid to semi-arid conditions always vary from those in the 
 humid regions. In the regions of heavy rainfall the more soluble 
 materials are leached out by the carbonated waters, leaving the 
 more siliceous matter. The soils of the drier climates retain 
 and contain therefore a larger percent of soluble material and 
 wait only for irrigating waters to make this material available 
 for crops. 
 
 STORAGE OF WATER. When sediments are laid down in 
 the ocean, or in gulfs and bays, there is locked up in them large 
 volumes of water varying from 25 to 50 per cent of the volume 
 of the sediment, according as the pore space is large or small. 
 All rocks contain more or less water, even hard marble absorbing 
 0.23 per cent of its weight. The storage capacity of soil generally 
 is in round numbers two feet of water to five feet of soil. Sand 
 and sandstones lying below drainage outlets may contain as high 
 as 38 per cent of their volume of water, and become storage res- 
 
30 Soils of California 
 
 ervoirs of great capacity. Clays range from 20 to 40 or even 
 50 per cent of their dry weight in stored water. 
 
 AIR RETAINED. The capacity of water to retain air con- 
 densed within itself increases with the air pressure to which it is 
 subjected. Air does not readily escape from the spaces of a fine 
 grained soil, especially when the soil is saturated with water. 
 
 ICE BENEATH THE SURFACE. The water which freezes 
 within the soil has an efifect upon the surface. Stones and boul- 
 ders work up through the soil as freezing and thawing alternate. 
 The frozen water in the soil makes it solid and prevents surface 
 erosion. If the water in ponds, streams and lakes is shallow the 
 water freezes to the sand and gravel and boulders at the bottom, 
 loosening and moving them. 
 
 WORK OF UNDERGROUND WATER. Rain water is 
 pure, but water from wells and springs contains mineral matter, 
 showing that the rain water after sinking underground has dis- 
 solved mineral matter. One mineral in solution may be exchanged 
 for another, the lime carbonate of a shell may be removed par- 
 ticle by particle, and some other mineral such as silica be left in 
 its place ; or cementing material may be deposited in a soil, form- 
 ing a hardpan. Materials taken from rocks in one place may be 
 added to a soil in another place. Rock minerals in one place 
 may be made porous, making the soil lighter ; and in another place 
 the pores of. the soil may be closed, indurating or hardening the 
 soil. New minerals are developed out of the old by addition, 
 subtraction, or division of the minerals. In fact the mantle rock 
 of soil and subsoil represents the residium of this working over 
 of the material from the bedrock, or of the original material 
 before it is transported to the soil area where it remains. 
 
 The underground water moves large masses of material at 
 times. It saturates masses of earth and rock, increasing the 
 weight and destroying the adhesion between layers, as where rock 
 or soil rests on clay, and masses give way, forming landslides. 
 Streams of stones moving steadily but very slowly down steep 
 slopes are a form of slide called screes. At the foot of cliffs and 
 steep slopes there is generally a talus, or heap of rock fragments 
 fallen from above. 
 
 DRAINAGE. When a land surface is young, or recently ele- 
 vated above the sea, the run-off fills the depressions, forming 
 
Processes 31 
 
 lakes, ponds and marshes. On the low plains, drainage develops 
 slowly and remains imperfect for a long time. The shallow lakes 
 of the glacial drift high in the Sierras are being slowly filled with 
 mud and peat which will form soils there in the future. 
 
 The diameter of the soil grains and the amount and form 
 of the pore spaces determine the amount of water which can 
 pass through a soil in a unit of time. The pore spaces are deter- 
 mined by both the size and the arrangement of the soil par- 
 ticles, and may vary from 25 to 45 per cent of the volume of 
 the soil. Underdrainage removes water from all except the 
 capillary spaces and leaves the other spaces free to air circulation. 
 There is also an upward movement of the air from the drains to 
 the surface which aids in the aeration of the soil. Seepage is the 
 movement of water through the fine pores of the soil under the 
 stress of gravitation. It begins when water enters the soil and 
 ends where the water escapes into passages larger than capillary. 
 The moving power is the hydrostatic pressure of the water itself, 
 and this pressure is increased or lowered according to the pressure 
 of the atmosphere, varying with high and low barometer. The 
 flow of water from tile drains will vary as much as 15 per cent 
 with the barometric changes. 
 
 GRADATION. The run-off forms streams, and a stream in 
 times of flood cuts its channel deeper, and the overflow deposits 
 sediment on the adjoining floodplain. In other words the stream 
 in flood degrades or scours its channel, aggrades or fills up its 
 plain. As a result of its varying velocities in flood and in low 
 water, a stream may deposit coarse material at one time, and fine 
 material at another. Floodplain deposits, or soils, therefore vary 
 from the finest mud, through sand and gravel to boulders. When 
 a rough piece of land is prepared for irrigation it is graded by 
 cutting down the high places and filling up the low. The same 
 process is going on all over the world, mountains, plateaus, and 
 hills are being worn down and the material deposited in valleys, 
 basins and over the lower plains. Lowering the level of the land 
 is called degradation, and raising the level is called aggradation, 
 while the result of the two processes is called gradation. As a 
 country grows smoother and is reduced by gradation to a plain of 
 low relief, not far above sea level, it is called a peneplain (almost 
 a plain). Young low plains are smooth and gently sloping, easily 
 accessible, easily cultivated and generally productive. 
 
32 Soils of Califobnia 
 
 STREAMS- If any stream is followed up it is found to divide 
 into smaller branches and rivulets, as a tree divides above the 
 trunk into branches and twigs. Take any of the rivers for ex- 
 ample. Near its source in the high Sierras the slopes are steep, 
 the current swift, the channel narrow or canyon like, and are filled 
 with boulders : lower dow^n the slope is more gentle and the water 
 course consists of a wide outer valley which the stream covers only 
 at high water, and a narrower channel winding irregularly from 
 side to side; still lower the valley becomes very much wider and 
 consists of an extensive floodplain, and the channel follows a 
 meandering course full of bends and horseshoe curves ; and finally 
 the river reaches the sea through a delta or a series of sloughs 
 and bayous. 
 
 TRANSPORTATION OF SEDIMENT. We generally 
 think of a stream as a stream of water only. It is also a stream 
 of mantle rock or soil held in suspensioji. Streams are the circu- 
 lation system of the earth, carrying nourishment to all parts. In 
 the human system the blood goes from the heart and carries in 
 suspension the digested foods to all parts and picks up and carries 
 away used-up products, until the life-giving stream is overloaded. 
 Then it passes into the lungs and the impurities are burnt out by 
 the oxygen of the air. The rains descend upon the mountains 
 and form streams that take up soil material, plant food, and car- 
 ries this down and distributes it where it is needed, and also picks 
 up its loads of used material, or waste, until overloaded it dumps 
 itself into the ocean where the waste material is washed out. 
 
 The ocean is the great septic tank of the world. Here waste 
 material is deposited to form sediments or soils for generations 
 yet to come. Evaporation carries the pure water up to the clouds 
 and back to the mountains, to be precipitated again, completing the 
 cycle of the waters. 
 
 Thus the surface of the earth, the soil, is the growing, living, 
 changing part with its circulation system that is analagous to the 
 blood of animals and the sap of vegetation . 
 
 The size of the rock particles which a stream can carry in 
 suspension increase as the speed of the current increases. A cur- 
 rent of one-third of a mile per hour can carry clay; two-thirds 
 an hour can carry sand ; two miles per hour, pebbles the size of 
 a bean ; four miles an hour, stones the size of an egg ; while a 
 mountain torrent will move huge boulders. 
 
Pbocesses 33 
 
 A stream carrying all the sediment it can is said to be loaded, 
 or it may become overloaded and have to deposit some of its 
 burden. 
 
 DEPOSITION. A stream flowing down a steep hill or moun- 
 tain side erodes a gully, or canyon, and deposits at the mouth of 
 a gully a conical or fan-shaped heap forming an alluvial cone, or 
 flat fan. 
 
 Illustrations of this may be seen on a small scale anywhere 
 after a rain. 
 
 The rivers descending from the great Sierras build extensive 
 fans at the base of the range, such as that of the Merced River 
 which has a fan with a radius of 50 miles. Where the alluvial 
 fans are so large as to join, forming a continuous plain, such as 
 are found all along the east side of the San Joaquin Valley, or the 
 base of the Sierra Madre, it is called a piedmont (foot of the 
 mountain) alluvial plain. These are easily irrigated as the water 
 spreads naturally over the land and can be easily carried to any 
 part. When a stream overflows its banks it deposits sediment on 
 the flooded ground forming an alluvial plain. At the mouth of 
 the river the alluvial plain extends into the lake or sea, forming 
 a delta. At the head of the delta the stream often divides into 
 distributaires and enters the sea or lake by many mouths. The 
 soil of a flood plain, or of a delta, is often so fertile that it pays 
 to protect it by dikes. Streams towards their mouths may become 
 overloaded with sediment, the channels become shallow and 
 crooked and constantly changing and in some cases the river be- 
 comes divided into a network of small streams and is said to be 
 braided. 
 
 RECENT STREAM DEPOSITS. With every heavy rain 
 the streams traversing the foothill valleys become heavily laden 
 with sediments washed from the surface of the bordering slopes. 
 Upon entering the valley, the streams overflow their banks, the 
 water spreads, the velocity of the current is suddenly checked, 
 and the coarser sediments, consisting say of fine sands and silts, 
 are deposited, covering the original material of the valley slopes 
 with a thin layer. In this way some of the streams have built up 
 along their flood plains a slight ridge, the summits of which they 
 traverse, until the slopes of the stream beds reach a minimum, 
 when they break through the enclosing ridge, seek new channels, 
 and build up other low broad ridges. These streams finally enter 
 
34 Soils of California 
 
 the valley trough where the drainage is deficient and water fre- 
 quently stands during the rainy season, and it is here that the finer 
 silts and clays are deposited. 
 
 CROOKEDNESS OF STREAMS. The current of a wind- 
 ing stream is swifter on the outside of the bend, and it cuts the 
 bank there and deepens the channel. The slower current on the 
 inside of the bend drops its part of the load, building up a bar of 
 mud or sand. 
 
 VALLEY FORMS. A swift stream uses the sand and gravel 
 it carries as tools that saw their way down through the hardest 
 rocks. Thus the region through which the Colorado River runs 
 in Colorado and Arizona is slowly rising, and the river cuts its 
 way down, ever deepening its canyon. A swift stream cuts the 
 bottom faster than the sides, cutting deep narrow valleys such as 
 are found in the canyons of the Sierras. A slow stream cannot 
 sweep the bottom clear, and winds cutting the sides and wearing 
 away its banks, forming in time a wide valley. A stream which is 
 actively deepening its valley is young. A stream which has cut its 
 valley down so as to smooth out its falls and rapids has reached 
 base level and is mature. A stream which has widened its valley 
 and aggraded its flood plain has reached old age. 
 
 LEVEES. As a river overflows its banks, the current is 
 checked rather suddenly and the larger and coarser sediment is 
 dropped near the channel, thus building up a bank above the level 
 of the flood plain, forming a natural levee. The floods leave a 
 thin layer of fine fertile mud or silt over the submerged land, 
 forming a soil of great fertility that is often renewed. 
 
 LAKES. Lakes, ponds and marshes are bodies of standing 
 water which occupy depressions in the surface of the land. They 
 are never stable, but are ever changing. (1) Waves wear the 
 shore and the material from this is assorted and deposited; (2) 
 streams carry their loads of mud, sand, and gravel into the lakes 
 and leave them there; (3) winds blow in sand and dust; (4) 
 animal forms of Hfe live and die there leaving their bones or 
 shells; (5) plants grow in the shallow waters and their material 
 accumulates on the bottom ; (6) the lake is drained by the cutting 
 deeper of the outlet; (7) in cold regions ice crowds the shores 
 and eflfect changes; (8) in the arid regions minerals are precipi- 
 tated from solution. All this accumulation of material raises 
 
Processes 35 
 
 the bottom of the lake and reduces the water capacity of the 
 basin. If the rainfall exceeds the annual evaporation, and the 
 outlet cannot carry off the water the lake increases in size, spreads 
 out over more land, but is shallower; plants accumulate, and a 
 marsh peat bog, or meadow is formed. Where the sediments 
 deposited in the lakes are made up largely of the shells of fresh 
 water animals, the calcareous secretions of plants, or lime pre- 
 cipitated from solution, such deposits are called marl if they are 
 soft. 
 
 In the arid regions where the evaporation exceeds the rain- 
 fall, the depressions in the floor of the basins All up with water 
 in the wet seasons and evaporate in the dry seasons, leaving bodies 
 of salt, soda, borax, etc. These are properly called intermittent 
 lakes, but are locally known by many names, such as "dry lake," 
 "soda lake," "borax lake," "alkali lake," "desert sink," etc. Gla- 
 cial lakes are hollows in the bedrock eroded by moving ice, or 
 hollows made by deposits of drift forming dams. Examples are 
 numerous in the higher portions of the Sierras. Volcanic lakes 
 are old volcanic craters filled with water : or are caused by the 
 damming of a stream by a lava flow. 
 
 GLACIERS. These ice streams are slow, stiff and awkward 
 compared with a river, but are prominent factors in the making 
 of many soils, as they are great soil mixers. A glacier tears loose 
 rock fragments at its head, eating slowly into the mountain side, 
 forming a vast hollow called a cirque, and the ice stream several 
 hundreds of feet in depth grinds the rock underneath into flour 
 called bergmeal. The thick accumulations of drift at the end of 
 a glacier, or edge of an ice sheet, is the terminal moraine. A gla- 
 cier does not have the sorting power of water so that its material 
 is a mixture of all kinds of rocks, cobbles, pebbles, sand and clay 
 confusedly intermingled from the finest to the coarsest and is 
 easily recognized as glacial drift. The land worn down by glacial 
 action is left barren bedrock, or with a thin mantle of coarse 
 material, rendering agriculture impossible. The vegetation of 
 such a soil generally consists of coniferous forest. The bulk of 
 glacial drift is composed of boulder clay, a stiff clay containing 
 pebbles and boulders. Glacial drift ridges are called marginal 
 moraines, formed along the edges of the melting ice sheets, kames 
 are the irregular heaps of sediment formed where water escapes 
 from the ice, eskers are sharp winding ridges of sand and gravel 
 
36 Soils of Califobnia 
 
 deposited in stream channels under the ice ; and drumlins are 
 lenticular or prismatic hills of clay. Glacial streams are as a rule 
 aggrading streams and develop alluvial plains called valley trains, 
 or deltas, where they enter lakes, bays, or other streams. 
 
 The soils of California owe much to glacial action, for glaciers 
 not long ago covered large portions of the higher ranges, and 
 small glaciers still exist on the sides of Mt. Shasta where their 
 action in soil forming may be studied. The glacial lakes near 
 Lake Tahoe and at the head of the Yosemite Valley give excel- 
 lent opportunity to study moraines, kames, eskers, and drumlins. 
 
CHAPTER V 
 
 CALIFORNIA TOPOGRAPHICAL PROVINCES 
 
 California is the result of the geologic forces of the past, and 
 the agencies at work today. It is not to be expected that the geo- 
 logic history of all parts of such a vast area are the same. The 
 regions or large areas having the same history are known as 
 provinces. These provinces may be studied according to their 
 relief forms or topography and climate, or according to their geo- 
 logic history. Considering first from the topographic standpoint 
 we find abundant reasons for its diversity in soils and crops. 
 
 AREA. California lies between the parallels of 32 degrees, 
 30 minutes north latitude and 42 degrees, thus stretching through 
 nine and a half degrees of latitude. This line on the Atlantic 
 coast would reach from Edisto Inlet in South Carolina to Cape 
 Cod, Massachusetts. 
 
 The extreme distance from the northwest to the southeast 
 corner is 775 miles. The maximum width is 233 miles, and the 
 minimum is 148. The total area is 158,360 square miles, of which 
 the land area alone is 155,980 square miles. The coast line along 
 the Pacific measures 1,200 miles. It is larger than the combined 
 areas of New York, Massachusetts, Connecticut, New Jersey, 
 Delaware, Maine, Vermont, New Hampshire, and Ohio. If one 
 considers the diversity of soils existing in all the states mentioned, 
 it is natural to expect so large a state as this to contain a very 
 wide range of soils. It is naturally divided into six provinces, 
 each of which has some soils not found elsewhere, and other soils 
 in common with other portions of the state. 
 
 THE SIERRA NEVADA PROVINCE. The Sierra Nevada 
 range is not only longest in the state but it is the highest in the 
 United States, forming a gigantic wall along the eastern edge of 
 the central portion of the state. In form, it is like an immense 
 and irregular lense-shaped table that has been tilted up along its 
 eastern edge, showing a bold precipitous face to the desert on 
 the east, but sloping as a whole gently towards the Great Valley 
 on the west. 
 
38 Soils of Califobma 
 
 The Range proper terminates on the north near Lassen Peak, 
 and on the south at Tejon Pass. The crest Ues close to the eas- 
 tern edge and its skyHne is marked by hosts of snow-clad peaks 
 towering from 10,000 to 13,000 feet above the sea, culminating 
 in Mt. Whitney, 14,502 feet above the sea. 
 
 The rainfall among the peaks ranges from 70 inches in the 
 northern part in Sierra County to 60 in Eldorado County, and 50 
 in Madera County. It diminishes from this to the rainfall of the 
 foothills bordering the great valley on the west. Few realize the 
 extent of the great watersheds included in this mighty range, or 
 the volume and value of the streams descending from it. The 
 following areas were carefully computed by state and national 
 engineers, and measure the watersheds from the edges of the 
 valleys to the head of the streams. Beginning on the north and 
 coming south the tributaries to the Sacramento River from the 
 Sierras are as follows : Feather River 3654 square miles, Yuba 
 1358, Bear 287, and American 1899. The tributaries to the San 
 Joaquin River are : the Consumnes River 580 square miles, Jack- 
 son 283, Mokelumne 657, Calaveras 491, Stanislaus 1051, Tu- 
 olumne 1501, Merced 1076, Chowchilla 268, head of San Joaquin 
 1637, Kings 1742, Kaweah 619, Tule 437, and Kern River 2345 
 square miles. 
 
 The San Bernardino, Sierra Madre, and San Jacinto ranges 
 are the southern extension of the Sierra Nevadas, and their geo- 
 logic history is closely the same. They range from 5000 to 10,- 
 000 feet in height, culminating in Mt. San Bernardino (Grayback) 
 11,725 above sea level. They are drained by the Los Angeles 
 River 568, San Gabriel 512, Santa Ana 1540, Santa Margarita 
 731, San Luis Rey 566, San Diego 409, Sweetwater 216, Otay 
 145, and the Tia Juana River 499 square miles of watershed. 
 
 The Sierras are covered with the National Forest Reserves 
 and are given up to lumber, cattle and sheep industries, with more 
 or less farming in some of the valleys. 
 
 THE COAST PROVINCES. The Coast Ranges include all 
 of the mountain ranges lying west of the Great Valley and the 
 other provinces and extending to the ocean. There is no well 
 defined central axis, either topographic or geologic, but the range 
 consists of a number of parallel ridges 3000 to 4000 feet high, 
 with occasional peaks. The rivers are short and the drainage 
 areas much smaller than those of the Sierras. 
 
Califoenia Topographical Peovinces 39 
 
 The northern Coast Range, or that extending north from San 
 Francisco, is drained principally by the Eel River which has a 
 basin of 3,552 square miles, the Mattole has 225 square miles, 
 the Novo 126, Big 164, Navarro 248, Russian 1515, Gracia 82, 
 and Gualala 351. The rainfall varies from 40 inches near the 
 coast to 30 inches on the eastern side. While lumber, cattle and 
 general farming predominate in the northern portion of the range, 
 the central and southern portions are noted for their extensive 
 orchards, vineyards, and intensified farming. 
 
 The south Coast Range extends from San Francisco to San 
 Diego and is drained by numerous short but important rivers that 
 supply water for irrigation. At the south end at San Diego this 
 range merges with and forms the foothills of the southern Sierras 
 and the rivers are classified with the Sierras. With this excep- 
 tion the drainage areas are as follows : Guadalupe River 201 
 square miles, Pescadero 80, SaHnas 4714, San Luis Obispo 78, 
 Santa Maria 1806, Santa Ynez 836, and Santa Clara 1576 square 
 miles. 
 
 The rainfall in the mountains is from 30 to 50 inches, varying 
 with elevation. In the foothills it is from 20 to 30 inches ; and 
 in the valleys from 10 to 20 inches. The valleys are relatively 
 broad and of gentle slope, and in general given over to intensive 
 cultivation under irrigation of crops that are specified in connec- 
 tion with the soil descriptions. 
 
 THE GREAT VALLEY. One of the most striking features 
 of California is the great central valley, some 400 miles long, 
 which extends for nearly two thirds the length of the state. It 
 lies between the Sierras on the east and the Coast Range on the 
 west. The northern portion is drained by the Sacramento River 
 and the southern portion by the San Joaquin, the two rivers meet- 
 ing close to the point where they empty into San Francisco Bay. 
 These rivers are fed by the many large streams already mentioned 
 in the Sierra Province. The Coast ranges supply only a small 
 amount of water to the valley. The Great Valley is a great 
 synclinal trough partially filled with the debris from the gradation 
 of the ranges that enclose it. 
 
 The elevation varies from slightly above sea level to below 
 mean tide, near the bay, and to about 100 feet above sea level at 
 Marysville Buttes, and 800 feet a little ways north of Redding. 
 The San Joaquin valley is only 420 feet above sea level at Bakers- 
 
40 Soils of Caxifobnia 
 
 field. The middle or bottom of the valley is a vast plain without 
 rock outcrops, bluff, or terrace, with sluggish streams and tidal 
 sloughs. On either side are the uplands, consisting of rolling, 
 sloping plains which reach to the foothills. The rainfall at the 
 north end in Shasta County is from 30 to 50 inches, decreasing 
 towards the south to from 10 to 20 in the central portion, and 
 from 20 to 30 inches along the bordering foothills. The crops 
 are described in detail in connection with the soils. 
 
 THE GREAT BASIN. This is the western portion of the 
 great Cordilleran region that has no outlet to the sea, and extends 
 from the foot of the Sierras to the eastern boundary of the state. 
 The northern portion is small, covering the region from Honey 
 Lake in Plumas County to Goose Lake in Modoc County. The 
 southern portion covers most of Mono, Inyo, San Bernardino, 
 and Imperial Counties, the eastern portion of Riverside County, 
 the northern portion of Los Angeles County, the southeast part 
 of Kern County, and a part of the east edge of Ventura County. 
 It is not a cup-shaped depression gathering its waters at a com- 
 mon center ; neither is it a vast level covered by desert lands. It 
 is a broad area of varied surface, valleys, plains, mountains, and 
 many independent drainage districts, and contains many important 
 communities of prosperous people. Its general elevation in Cali- 
 fornia is from 4000 feet above sea level in the northern portion 
 to 2000 feet in the southern portion, descending finally to sea 
 level and even below. Isolated mountain ranges rise from 2000 
 to 3000 feet above the general surface of the basin. Between 
 the ranges are smooth valleys, whose alluvial slopes are floors 
 built up of debris washed through long ages from the ranges. 
 These valleys are generally trough-like, merging enough to assume 
 the character of plains. Locally they have been miscalled deserts, 
 as the Mojave, Amargosa, and Colorado deserts, the proper name 
 being arid districts ; for under irrigation, prosperous communities 
 now occupy extensive portions of the former so-called "deserts." 
 
 The lowlands and mountains are generally treeless, except for 
 fringes of cottonwoods along the streams and straggling brushlike 
 cedar in the mountains. The rainfall averages from 2 to 5 
 inches; but the storms result mainly from the irregular and often 
 violent local disturbances in the mountains and sooner or later 
 the "cloud burst" visits every locality. 
 
 The aridity is most apparent when compared with that of the 
 
California Topographical Provinces 41 
 
 great plains lying between the Mississippi River and the Appa- 
 lachian mountains of the east. On the eastern plains the average 
 moisture contents of the air is 69 per cent of that necessary for 
 saturation and rainfall : in the Great Basin it is 45 per cent. The 
 rainfall of the plains is 43 inches, and that of the Basin from 2 
 to 5. The evaporation from the surface of Lake Michigan is a 
 layer of water 22 inches deep ; from the Great Basin it is 80 inches 
 per year in the north and reaches 150 inches in the south. 
 
 Owen's River Basin is one of the minor divisions of the Great 
 Basin. It lies at the eastern foot of the Sierra Nevada in Inyo 
 County, just east of the highest peaks in the United States, Mt. 
 Whitney (14,502) and Mt. Lyell (13,090), and has a watershed 
 of 2630 square miles. While the river is only 125 miles long, it 
 is fed by over 40 lateral tributaries which rise from the glacial 
 lakelets and marshes along the east crest of the highest Sierras. 
 It furnishes not only water for Los Angeles City, but irrigating 
 waters for the sloping alluvial plains that are made up largely of 
 merged delta fan surfaces. These plains are covered with deep 
 granitic alluvial soils which vary from sands to sandy loams. 
 The valley is extensively cultivated and is particularly adapted 
 to stock raising. The Honey Lake region and north to Goose 
 Lake is a plateau region consisting of valleys dotted with sage 
 brush and rugged isolated mountains. The general elevation is 
 4000 feet, the buttes and local ranges rising from 1000 to 5000 
 feet higher. The soils are mainly residual from the lava which 
 weathers into a light but very fertile soil. There are large areas 
 of cultivated land and still larger stretches of barren lava table 
 lands. The Mojave Valley district lies to the north of Mt. San 
 Bernardino. The Mojave River is 100 miles long but preserves 
 its life by concealment, creeping through the gravel and betray- 
 ing its existence only where cross ledges of rock force it to the 
 surface. It drains an area of 1470 square miles, of which 251 are 
 mountains, 219 foothills and 1000 of arid plains and barren 
 buttes. The valley is devoted to alfalfa and farm produce with 
 here and there fine orchards. The soils are sands and sandy 
 loams, generally micaceous and fairly free from alkali. Antelope, 
 Rock Creek and several other subdistricts might be described 
 which are within the boundaries of the Basin, but receive irriga- 
 tion waters from the great ranges which they border, their soils 
 being rich sandy loams and sands, with here and there some ad- 
 mixture of the clays. 
 
42 SoUiS OF Calitobnia 
 
 THE CASCADE PROVINCE. The Cascade Mountains 
 form the southern extension of the great lava covered range of 
 Oregon, and includes the region from Mt. Shasta east to the 
 Great Basin, and south to the Sierra Nevada, just touching the 
 extreme north end of the Great Valley. Mt. Shasta, 14,380 feet 
 elevation, is the culminating peak, the region descending eastward 
 to the plateau of the lakes 4000 feet, and southward to the head 
 of the Great Valley, which is about 800 feet above the sea level. 
 Nearly all of its drainage enters the north end of the Great Valley 
 and runs into the Sacramento River, the tributaries and their 
 watersheds being the Pitt River, 4597 square miles ; head of Sacra- 
 mento River, 538; McCloud River, 678; Battle Creek, 337; An- 
 telope Creek, 129; Mill Creek, 154, and Ditch Creek, 192 square 
 miles. The region is heavily timbered and the agricultural por- 
 tions small. 
 
 THE KLAMATH PROVINCE. The Klamath mountains 
 extend from Oregon south into this State over 200 miles. The 
 name includes the local ranges known as the McCloud, Trinity, 
 Bully Choop, Scott, Salmon and other mountains, whose geologic 
 and soil histories are essentially the same throughout. The prov- 
 ince is covered by rugged ranges from 5000 to 10,000 feet high, 
 and is accessible only by wagon roads. It is given up mainly to 
 mining, timber, cattle and sheep, with some farms in the broader 
 valleys. The terraced stream valleys are often more than 2000 
 feet deep and range in form from V-shaped canyons to broad, 
 flat valleys. The rainfall in the eastern portion is 40 inches, but 
 west of the divides increases to 60, and near the coast reaches 
 70 inches. Nearly all of the drainage goes to the ocean from the 
 Klamath River with its 2468 square miles of drainage area, 
 Scott's River, 841 ; Trinity, 930; Smith, 691, and Redwood Creek, 
 285 square miles. 
 
CHAPTER VI. 
 CALIFORNIA GEOLOGIC PROVINCES 
 
 The geologic age of any soil, or the age of the rocks from 
 which it was derived is only of general interest and not always 
 of specific value in determining the adaptability of the soil to 
 crops. The classification of soils according to the geologic history, 
 however, give us clearer ideas of the origin and therefore the 
 character of soils in general, and it is worth while to glance at 
 the geologic history of the provinces. 
 
 SIERRA NEVADA PROVINCE. We speak of the hills and 
 mountains as everlasting and use them as symbols of permanency. 
 Geology, however, teaches us that they, like everything else in 
 the universe, have their birth, youth, maturity, old age and death, 
 and that their death, like that of everything else, means not an- 
 nihilation but change of form and another and a new existence, 
 and that ever in the line of advancement and progression in the 
 scheme of existence. 
 
 The great Sierra Nevadas of today are young mountains in 
 rugged and vigorous condition, doing their work as sky-line guard- 
 ians of the fertility of the plains below and their teeming forms of 
 life. They catch the moisture rising from the ocean and con- 
 dense it into rains and snow and store it among their crags to 
 irrigate the soils miles away. They give each rivulet and each 
 stream its load of material to carry down and build up new soils 
 and renew old ones. They were born during the later part of the 
 Jurassic time, but not to their present magnitude. By the end 
 of the Cretaceous they had been worn down almost to peneplain. 
 In the Eocene and Miocene they were cut and carved by rivers 
 having wholly different courses from those that exist today, 
 many of them leaving their gold-bearing gravels to pay for the 
 opening of the state to the farmer and fruit raiser of today. 
 Still later came the final uplift, when the towering crests 
 were covered with glaciers, the great soil mills of the earth, 
 whose waters fed lakes in basin and valley, where loads of sedi- 
 ment were deposited by hard-working streams busy in preparing 
 lake, or lacustrine, soils for the coming of mankind. The great 
 
44 Soils of California 
 
 mass of the Sierras is composed of granitic rocks, flanked in the 
 northern and central portion by long parallel belts of Jurassic 
 and Triassic slates and shales, and Mississippian limestones, and 
 flanked along the foothills at the edge of the Great Valley by 
 beds of Miocene and Pliocene sandstones, marls, limestones, 
 tuffs, clays, and shales ; the whole spotted here and there with 
 lavas ancient and recent. 
 
 The geologic history of the Sierra Madre, San Bernardino 
 and San Jacinto ranges and the rocks forming them is essentially 
 the same as that of the Sierra Nevada and they are included in 
 that province. 
 
 GREAT VALLEY PROVINCE. In its earlier geologic his- 
 tory the Great Valley has not always drained into the ocean by 
 way of San Francisco Bay. There is geologic evidence that it 
 has at other times emptied into the ocean at points farther south, 
 and it was not until later that faulting broke the mountains and 
 formed the Golden Gate. In earlier geologic times the valley was 
 submerged by the waters of a great inland lake, or by an arm of 
 the sea. The gradation of the Sierras laid down a vast quantity 
 of materials filling the valley to great depths. The great rivers 
 of the Sierras brought down sands worn from granite, quartz, 
 porphyry and lava and emptied them into the lake. These were 
 carried by the currents and distributed along the shores and over 
 the bed of the lake and deposited as stratified clays, sand and 
 gravel, or as beaches composed of gravel mixed with finer ma- 
 terial. Still later the land was elevated and the more or less con- 
 solidated accumulations were exposed to new weathering and 
 erosion. Great c|uantities of material were removed, leaving the 
 greater thickness of the beds along the edges and more elevated 
 slopes of the valley, often as rounded foothills of ferruginous and 
 calcareous conglomerates, partially weathered shales, interstrati- 
 fied with sand and silt. The subsequent weathering of this ma- 
 terial has given rise to residual soils along the foothills. 
 
 Some of this residual material, through the action of grav- 
 ity, or from heavy rains, has slid, or rolled, or been washed short 
 distances and accumulated as colluvial soils on the lower slopes. 
 More erosion has carried the finer portions of the deposits over 
 the valley slopes and along the flood plains of the larger streams, 
 forming alluvial soil. 
 
 The intermediate upland plains receive loams, clays, and clay 
 
California Geologic Provinces 45 
 
 adobes. The flood plains sandy and silty materials, and the river 
 bottoms and lowest plains receive deep fine alluvial sands, silts, 
 and clays. Naturally soils so formed shade into each other, the 
 boundaries being obliterated by recent modifying agencies of wind 
 and water. Each soil is subjected to considerable local variation 
 in color, texture, and crop value according to the local conditions 
 of wind, rainfall, and material on or away from the land, or 
 washed on to it from adjacent soils. 
 
 COAST RANGE PROVINCE. The Coast Ranges consist of 
 mountains that are roughly parallel anticlines, their corre- 
 sponding synclines forming the valleys. The formations north 
 of San Francisco consist mainly of Jurassic rocks in the interior, 
 and Cretaceous rocks next to the coast. South of San Francisco 
 the ranges are mainly Miocene and Pliocene formations with 
 some Cretaceous and Jurassic. The rocks are mainly shales and 
 sandstones with occasional igneous rocks. Residual soils were 
 first formed from these rocks, and are found on the ranges and 
 higher foothills. This was followed by the creeping of coUuvial 
 soils down the slopes, and the washing of alluvial soils over the 
 flats. The shales have imparted a somewhat heavy character 
 to the soils through weathering into silts and clays, but the sand- 
 stones have relieved and lightened the soils by the sands washed 
 or blown into them. 
 
 GREAT BASIN PROVINCE. This great arid region is a 
 closed basin into which the rainfall drains to the lowest depres- 
 sions and then evaporates. This action leaches the soils and the 
 minerals dissolved out accumulate in the low depressions, form- 
 ing deposits of soda, salt, borax, etc. The basin is occupied by 
 many mountain ranges, most of which dip westerly. The type of 
 structure is that of the faulted monocline, or block tilted up at one 
 edge or corner. Many of the ranges are formed of pre-Cambrian 
 granites and schists, and show along their flanks exposures of 
 Cambrian, Ordovician, Silurian, and Devonian rocks. Most of 
 the valleys between the ranges are covered with eolian sands. 
 Extensive areas are covered with Tertiary or later lavas. All 
 these rocks give rise to vast areas of arid, rough, stony soils not 
 suited to agriculture and therefore not mapped or classified by 
 the U. S. Bureau of Soils. Certain areas close to the flanks of 
 the main range, such as the Owens Valley, Antelope Valley. 
 Mojave Valley, and the Imperial region are exceptions, as they 
 
46 Soils of California 
 
 receive more rainfall, and water can be brought from the moun- 
 tains and rivers for irrigation. 
 
 The Great Basin is, however, of as great importance to the 
 state in general as is a good furnace to the equipment of a palace. 
 It is the place where the atmosphere is quickly heated in the day- 
 time and rising tends to create a vacuum towards which the mois- 
 ture-laden winds of the ocean flow, giving the rains in the moun- 
 tains, and the cool invigorating breezes to the coast lands and to 
 the Great Valley. The periodic changes of climate in the ages 
 past are recorded in the Great Basin in the rise and fall of former 
 great lakes, such as the lakes known to the geologists as Pa Ute 
 Lake, Lake Lahontan. and others. Their terraces still exist, show- 
 ing various periods of increasing and decreasing rainfall and 
 evaporation, each of which meant soil building under varying 
 conditions. 
 
 CASCADE PROVINCE. The Cascade mountains form the 
 southern extension of the great lava covered range of Oregon 
 that comes south a short distance into this state. This range in 
 Oregon shows the underlying core of granites and slates of the 
 Jurassic time, and the heavy limestones of the Carboniferous, 
 similar to the Sierra Province. In California, however, lavas 
 and other effusives of the Tertiary and later times cover most of 
 the country within this province. The residual and colluvial soils 
 from the lava are rich in plant food, and where water can be ob- 
 tained produce crops in abundance. 
 
 KLAMATH PROVINCE. This region is made up of forma- 
 tions older than those of the Sierras. Rocks of the Cambrian, De- 
 vonian, and Mississippian and other periods of the Paleozoic age 
 have been identified, flanked on the south by the Comanchean and 
 Jurassic. It was reduced in Cretaceous time to a peneplain, and is 
 now a high mountain plateau rejuvenated by late uplifts, the 
 rivers deepening and widening their channels. It shows the ef- 
 fect of glacial action and lava flows. The soils of the valleys are 
 sands and gravels mixed with silts and clays. 
 
PART III 
 
 CHAPTER VII. 
 SOIL CLASSIFICATION NECESSARY 
 
 COMMON NAMES ARE MISLEADING 
 
 It has been a recognized fact since the dawn of history that 
 soils differ, and many names have been given them. Many of 
 the names in common use have a local value only and are mislead- 
 ing when used away from their home locality. Most of them 
 should be used simply as descriptive adjectives, as they are use- 
 less as names for scientific comparison and correlation of soils. 
 A single soil may have several local names in the same state, and 
 the common name is often given totally different soils in different 
 states. This confusion in names often means loss of time and 
 money, and sore disappointment to new settlers. A large number 
 of common names are mere nicknames, quite appropriate in the 
 region where they originate, but wholly misleading and mischiev- 
 ous when transplanted to regions having different climates, dif- 
 ferent geologic formations, and different local conditions. A 
 little examination into soil names in common use will show 
 the necessity of having standard methods for classifying, com- 
 paring, and naming soils, such as that adopted by the U. S. Bu- 
 reau of Soils. For example, this bureau has named a soil in 
 Ohio, the "Miami Clay Loam," having a definite origin, definite 
 physical characters, and definitely adapted to certain crops ; yet 
 this soil is locally known in various parts of Ohio as Sugar Tree 
 Soil, Clay Upland Soil, Limestone Soil, White Clay Soil, Red 
 Clay Soil and Beach Land Soil. In Texas clays are variously 
 known as Ashy Flats Soil, Black Waxy Land Soil, Boggy Land 
 Soil, Highland Soil, and Tight Soil. Peat, muck and swamp soils 
 are often called Acid Soils on account of the humic acid they con- 
 contain. No sharp line can be drawn in many cases between al- 
 luvial soils and those made by the wind, yet the term Aeolian, or 
 Eolian, is convenient when speaking of the origin of many soils, 
 but is a misnomer for other soils that are really largely alluvial in 
 
48 Soils of Califobnia 
 
 origin. The soils of the most productive portions of California 
 are soils of the arid region, but are not Arid Soils. This term 
 properly used applies to the soils formed where the rainfall is 
 small in distinction to soils formed where the rainfall is large, and 
 has nothing to do with their fertility, or adaptation to crops. A 
 common name in Maryland and elsewhere for any non-productive 
 soil is The Barrens, but in Alabama it means only the lands where 
 there is scant timber. The character of trees or vegetation grown 
 often gives the name as the Beech Land Soil, which applies, how- 
 ever, only to clay land in Ohio. Beeszvax and Canebrake soils are 
 found in Alabama, while Chocolate Soil comes from South Caro- 
 lina. The Blue Grass Soil of Kentucky is famous, but many soils 
 that are not from limestone are adapted to this grass. Such names 
 as Black Soil, Black Land, Black Prairie may mean the silt loams 
 of Illinois and Wisconsin, the loams of Ohio, the clay loams of 
 Virginia, or the dark clays of Mississippi or Texas. The black 
 jack oak trees give the name Black Jack Soil to clays, clay loams, 
 and gravel in the Carolinas ; but in Georgia soils growing the oaks 
 as well as the mayhaw are known as Black Gum Soil. The clay 
 loams of Michigan are known as Black Walnut Soil, while the clay 
 loams of Texas are called Black Post Oak Soil. The use of the 
 name Black Ash Soil is even more diverse. Baybush Pocoson, 
 or Pocoson, means a swamp land that is not subject to overflow, 
 in North Carolina, and Brier Pocoson, or Gallberry Land, is 
 named in Maryland for the vegetation without reference to the 
 flooding. A famous cotton soil of the South is known as Buck- 
 shot Soil because it crushes into grains, or buckshot, when dry. 
 In North Carolina they have the black spongy Buckleberry Soil 
 of the swamps ; in Louisiana sandy soils named for the Bullnettle 
 or Chinquapin. 
 
 A disintegrated rotten limestone combined with abundant 
 humus gives the well-known Canebrake Soil of the South. The 
 soil resting on bedrock is often called Capsoil, a term that lacks 
 the definiteness of the better name — residual soil. The Chalk 
 Soils of England and France that originate from, the chalk de- 
 posits are well named, but many whitish colored soils receive this 
 name that have no chalk in them. The name Cold Soil might 
 suggest that the land was retentive of water late in the spring or 
 was badly located on the north side of a mountain, but would 
 not point out the physical character of the soil as a name should 
 do. The crayfish live in soils where they do not have to go deep 
 
Soil Classification Necessaey 49 
 
 for water; hence we find the name Crawfish Soil in several 
 states. Cedar Soil, Chestnut Soil, and Cypress Soil are names 
 whose origin is obvious. The name Cumulose Soil was used for 
 some time but has given place to other names in late years. It 
 was applied to accumulations in situ for years or centuries of 
 organic and inorganic material in lakes that had no outlet : to the 
 peat, muck, or swamp soils in part at the head of valleys, in 
 deserted river beds, in river deltas and other partially drained 
 areas. Some soils in South Carolina are called Deadland Soil, not 
 because the clay lacks in fertility but because it is sticky and 
 hard to cultivate, that is not lively and not to be moved easily. 
 In the arid regions of the West, the Dust Soil rises in the air at 
 the merest puff of wind. The coarse detrital material caused by 
 a flood, such as a cloudburst in the arid regions, is called by 
 some Dilluvial Soil. An inappropriate name proposed for sedi- 
 mentary soils was Endogenous Soil, as objectionable as the term 
 Exogenous Soil which was proposed for transported soils. Fine 
 Soil is a term that should be used only with reference to the 
 texture of the soil, or as an adjective of praise, but not as a soil 
 name. The name Flat IVoods Soil is used for poorly drained 
 clays in Mississippi ; while similar similar soils are known in 
 West Virginia as First Bottom Land Soil, and as Flat Fine Wood 
 Soil in Florida. In the cotton states where the surface of the 
 lands has been eroded, exposing the unproductive subsoil, it is 
 called Galled Soil. The sands of California, the loams of Illinois, 
 and the mucks of the South, are all good Garden Soil. The resi- 
 due of coarse swamp grass, sedge, flag, etc., is called Grass Peat 
 Soil in some states. A general term for deposits from melting 
 ice sheets is Glacial Soil, which is more variable in character than 
 alluvial soils and in general is nearly as productive. The glacial 
 and boulder clay contain a variety of minerals finely ground and 
 intimately mixed, and are very fertile when they contain enough 
 sand and gravel to be pervious to water and workable. The 
 Glade Lands, or Conowingo Barrens of Maryland are very dif- 
 ferent from the Glade Soil or muck of Kentucky. Many soils 
 are derived from granitic rocks, but the name Granite Soil is 
 not more specific ; it may be a sand, loam, sandy loam, or some- 
 thing else. In Alabama some clays are called Gray Land, Gray 
 Prairie, or Gray Soil; but these names mean a sandy loam in 
 Virginia, a silt loam in South Carolina and Tennessee, a loam in 
 Texas, and a sandy loam in Georgia. 
 
50 Soils of California 
 
 The name Gumbo is well known from the Dakotas to the 
 Gulf of Mexico and west to the Pacific. It is not confined to the 
 clays but is loosely applied to any tough and very plastic soil that 
 is very sticky when wet and hard when dry. The name White 
 Gum Slash Soil and Glady Soil are Texan local names. A rough 
 sandy loam in Georgia is known as Rough Pimply Soil, and a 
 peaty clay in Mississippi is called Heavy Bottom Soil. The name 
 Hemlock Soil means a loam in New York and a sand in Michigan. 
 The name Hog Walloiv Soil indicates hummocks in California, 
 hollows in Texas, and land where the "hog-haw" trees grow in 
 Louisiana. Soils which are rich in humus are generally in better 
 physical condition than those low in this organic matter, as humus 
 is somewhat plastic and tends to hold the soil in a more loose 
 condition, but Humus Soil is a misnomer. The micaceous loams 
 of Alabama are called Isinglass Soil. The origin of the name 
 Ivyland Soil in North Carolina and the Jack Pine Soil in Michi- 
 gan are obvious. Soils formed where lakes have dried up are 
 geologicallv known as lacustrine or lake soils, but the term Lake 
 Front Soil a])plies only to the lands along Lake Erie in Pennsyl- 
 vania. The name Laterite (brick earth) is commonly applied to 
 any red soil, but its use should be restricted to red, iron-stained, 
 residual clay soil formed by the weathering of volcanic rocks. 
 
 Limestone Soil and Limestone Land indicate the origin of 
 the soil, which may be any one of several kinds. One term that 
 has been so loosely applied as to rob it of its significance both as 
 a geologic term and as a soil name is Loess. It is even misused 
 as synonymous with adobe. Its origin whether as eolian or sedi- 
 mentary,' or both, is still a matter of controversy. Any soil too 
 wet to give a solid footing is known as Looseland Soil in Delaware. 
 The term Marine Soils is general and applied to soils that consist 
 of stratified gravels, sands, silts, and clays deposited originally 
 in ofifshore water, and later raised above the sea level, where they 
 have not consolidated into rock and weather rapidly. Such 
 names as Marly Peat, Medium Peat, Peaty Loam, and Moss Peat, 
 can only be used locally. The Mesquite Soil is Nevada is sand, 
 and that of the mesquite flats or j)rairies of Texas is a clay loam. 
 The moors of Scotland give us the name Moor Earth. A general 
 term loosely applied is Mountain Soil. The rocks high up m the 
 mountains often consist of granites, gneiss, schists, slates, hme- 
 stones. and igneous rocks. These give rise to stony soils, or rough 
 broken areas best suited to forestrv, but the soils themselves may 
 
Soil Classification Necessary 51 
 
 vary from coarse gravels and sands to clays. The Mulatto Soil 
 or Mottled Soil of the South takes its name from its yellow color, 
 and is wholly different from the Niggerhead (boulders) lands of 
 New England. Many varieties of soils contain large amounts of 
 lime and are locally known as Marl Soil. Wherever oak trees 
 grow the term Oak Soil comes into use. The term Peaty Alkali 
 Soil is one that would puzzle most field analysts to identify. The 
 Piney Wood Land of Texas is a clay soil; the Pine Barrens of 
 Maryland is a sand; the Piney Woods of Alabama a loam; and 
 the Pine Flats of Arkansas a clay loam. The Post Oak Flats, 
 Post Oak Prairie, and the Post Oak Szvags from Virginia vary 
 from heavy clays to sandy loams. Pipeclay Soil is a local name 
 used from Maryland to California. Any treeless soil of the 
 middle west may be called Prairie Soil without reference to its 
 real character. 
 
 The name Redlands means a clay in xA.labama, Virginia and 
 Texas; a loam in Missouri; and a sandy loam in Georgia and 
 Wyoming. The Red Clay of Delaware is a silt loam technically 
 known as the "Norfolk Silt Loam," and the color is generally 
 yellow instead of red. In Virginia Red Clay Soil is generally 
 synonymous with Mulatto Soil. The dark clayey cotton soil of 
 India is known as Regur, a name that has lately been transplanted 
 to this country along with the Egyptian cotton. Flooded lands 
 along the sea coast are often called Salt Marsh Soils. All kinds 
 of soils have been called Scrub Oak Soil. Where soils are com- 
 posed of materials that have not been subjected to any appreciable 
 transportation they are often called Sedentary Soils, and by some 
 are divided into residual soils when they consist of residue left by 
 rock decomposition, and cumulose when they result from the 
 slow accumulation and decay of plant remains. Some loams in 
 Pennsylvania contain fragments of shale of the size and shape of 
 shoepegs and the soil is locally known as Slioepeg Soil. The com- 
 mon use of the names Silt Soils and Sand Soils means rock pow- 
 ders produced by the mechanical pulverization of various min- 
 erals, of which quartz is the most common. If the fragments are 
 not worn or rounded the sand is said to be sharp. Compare this 
 loose use of these names with the precise definition given on 
 another page. Any soil that is rich in available plant food is a 
 Strong Soil; any tenacious heavy soil is a Stiff Soil. 
 
 The most mischievous and misleading name is Sterile Soil, 
 apphed to any soil that does not produce vegetation of some kind 
 
62 Soils of Califobnia 
 
 naturally, such as the lands of the deserts, sandunes, lavas, etc. 
 It is nearly always a misnomer as the sterility is not due to the 
 inherent character of the soil, but to local conditions, such as 
 climate, lack of irrigating water, etc. In the humid regions many 
 soils that are said to be IVonwnt Soil, and sterile, are simply soils 
 that are sick, tired, abused or poisoned by toxins, and recover 
 all their vigor when restored to proper physical condition. 
 Swampy soils may be called locally Tamarack Soil, or for any 
 other tree that grows in them, or Tidal Soil if near the coast 
 where high tides submerge them. Sandy soils of glacial origin 
 are often called Till; while beds of volcanic ash are called Tuff 
 or Tuff Soil, but are light soils and never tough soils. Any soils 
 that water, ice, or wind have brought from higher levels and 
 deposited over lower lands are Transported Soils. Any soil con- 
 taining decomposed organic matter in an advanced stage of 
 decomposition, making it a rich soil for growing vegetables, may 
 be called locally Vegetable Soil, Vegetable Muck, or Vegetable 
 Loam. The English name JVacke is applied to a dark compact 
 clayey soil resulting from the decomposition in place of basaltic 
 rocks. Any dark colored or sandy soil that absorbs and retains 
 heat readily is a Warm Soil. Any soil that is easily washed away 
 by rains is a Wash Soil. The plastic clays of Virginia and Texas 
 are known as Wax Soil or Tallozv Soil. White Oak Soils are 
 loam or silt soils in Illinois and Maryland, and clay in Missouri. 
 A silt loam in the South is often called White Land Soil. It 
 shows a groping towards identification and classification when 
 the vernacular contains such terms as Beesivax Soil for sticky 
 clay in North Carolina ; Bugle Land Soil where the pitcher plant 
 grows in Georgia; Chaffy Soil or sands that the winds blow like 
 chaff in Delaware ; Sponty Soil that squirts up water when stepped 
 upon in Pennsylvania ; Yelloiv Prairie Soil for the treeless clay 
 loams of Alabama ; and Tight Soil tliat is hard to turn over 
 with a plow in Texas. 
 
 California has many local soil names which are noted with 
 the technical names in the latter part of the book. Thus we have 
 Dry Bog Land as a local name for the Portersville clay adobe 
 around Portersville; Dry Bog Adobe for the Portersville clay 
 loam adobe ; Dry Bog Soil for the Stockton clay loam adobe in 
 the Fresno region ; Foothill Soil for the Placentia loam adobe 
 around Santa Ana ; and Hogwalloiv Land for the Dunnigan clay 
 near Woodland. The Santa Cruz sandy loam is locally known 
 
Soil Classification Necessary 53 
 
 as Redwood Soil, where the redwoods {sequoia sempervirens) 
 grow. The Sacramento clay is known as Tule Land near Marys- 
 ville; the Fresno sandy loam of the San Joaquin Valley is often 
 called White Ash Land from its color and not for trees ; and the 
 same name is given locally to the Fresno fine sandy loam ; the 
 Feather silt loam is known as Black Land near Marysville. Wild- 
 goose Land is a nickname for the lower, poorly drained alkali 
 land, unproductive on account of alkali, occupying spots in the 
 Colusa area. The term White Alkali Soil is common for lands 
 where the soda salts are largely sulphates, and Black Alkali Soil 
 where the soda salts are carbonates. 
 
PART IV 
 
 CHAPTER VTII 
 SOIL PARTICLES 
 
 The soils of California include those of the coast, of the 
 coastal and interior mountain ranges, foothills and valleys. The 
 soils of certain type areas in each province have been classified 
 by the U. S. Bureau of Soils, Washington, D. C, and divided 
 into a number of series, varying in field characteristics, topog- 
 raphy, origin or mode of formation, and agricultural importance. 
 They range from the residual and colluvial soils of the mountain 
 sides, foot slopes, and foothills, to deep and extensive flood plains 
 and delta sediments, and ancient and modern marine and lacus- 
 trine deposits. While some of the series are confined to a single 
 coastal or interior mountain range or valley, others are of wider 
 range and extend over large areas in various parts of the state. 
 The value of these soils and their adaptation to crops is largely 
 dependent upon the possibilities of irrigation and upon local con- 
 ditions of rainfall and temperature, all of which are to a great 
 extent dependent upon the latitude and upon topography. They 
 range in agricultural importance from those devoted only to 
 extensive grain farming to the most valuable and intensively cul- 
 tivated lands devoted to citrus fruits, vines, and special crops 
 such as dates, cotton and rice. 
 
 In the present struggle for supremacy in commerce the 
 importance of accurate knowledge of agricultural conditions is 
 becoming daily more evident. It is important that the men who 
 control land and who are responiblc for its future value should 
 have at least a fundamental knowledge of the composition of the 
 common soils to furnish a foundation of facts upon which to 
 build a knowledge of agriculture. A ready working knowledge 
 sufficient for everyday use lies at the basis of success in every 
 industry and profession. The classification used here is taken 
 from the work of the U. S. Bureau of Soils. 
 
 ALL SOILS CONTAIN THE SAME MINERALS. One of 
 
 the most important facts established in recent years is that all 
 
Soil Particles 55 
 
 the common minerals are distributed through nearly all the soils, 
 and that normal soils in the most diverse regions are remarkably 
 similar in this respect, all the important soil minerals being pres- 
 ent in variable quantities. This fact has revolutionized the study 
 of soils and their treatment by the land owner. 
 THE NEW THEORY. The theory upon which the United 
 States Bureau of Soils works in their classification and correla- 
 tion of soils is that practically ALL SOILS contain sufficient 
 plant food for good crop yield, and that this supply is indcfinitc'v 
 maintained. That the productiveness of a soil depends even 
 more upon its PHYSICAL characteristics than on its chemical 
 composition. That every soil is intended to grow certain definite 
 crops, according to climate and local conditions, and that success 
 largely depends upon finding the proper crop for each soil. 
 SOIL PARTICLES. The basic material of the soil is an 
 aggregation of mineral particles ranging from two millimeters in 
 diameter to particles so small that they tax the power of the best 
 microscopes. The dififerent sizes of these particles and the dif- 
 ferent properties of the different sizes affect the texture, water- 
 bearing capacity, aeration, and other properties of the soil. The 
 minerals themselves are only slightly soluble, but have in the 
 aggregate absorptive capacity in a high degree. This provides a 
 dilute nutritive solution, or mineral soup, of sufificient strength for 
 the needs of the plants. It is evident therefore that the physical 
 analysis of the soils is far more important than the chemical or 
 mineralogical analysis. The modern study of the soil is based in 
 fact largely upon the physical structure of the soil, and upon the 
 soil solution. 
 
 SIZE OF THE SOIL PARTICLES. The study of the physi- 
 cal character of the soil begins with the particles that compose 
 it. If we consider each particle in a pure soil to be a sphere, 
 then the number of particles in a gram of pure soil may be cal- 
 culated, the result being as follows : 
 
 Number of Particles 
 
 Fine gravel 2. to 1mm 252 
 
 Coarse sand 1. to 0.5mm 1,72.3 
 
 Medium sand 0.5 to 0.25mm 13,500 
 
 Pine sand 0.25 to 0.1mm 132,600 
 
 Very fine sand 0.1 to 0.05mm 1,678,000 
 
 Silt 0.05 to 0.005mm 65,100,000 
 
 Clay 0.005 to 0.000mm 45,000,000,000 
 
 Since normal soils are a mixture of gravel, medium, fine and very 
 fine sands, silt and clay, the number of particles in the soil of 
 
66 Soils of Califobnia 
 
 a particular class will depend upon the number of particles present 
 of the above kinds. The approximate number of soil particles 
 present in one gram of soil has been calculated as follows : 
 
 Particles. 
 
 Sandy loam contains 6,485,000,000 
 
 Fine sand loam 6,902,000,000 
 
 Silt loam 9,639,000,000 
 
 Clay loam 16,371,000,000 
 
 Clay 19,525,000,000 
 
 The importance of these millions of particles in any mass of 
 soil lies in their relation to the surface area of each particle. 
 These grains are not in actual contact but separated from each 
 other by thin films of moisture, or in extremely dry soil by actual 
 air space. These spaces between the particles will differ in 
 size and shape according to the size and shape of the soil grains. 
 SURFACE AREA OF THE PARTICLES. The surface of 
 the particles holds the moisture, known as film water. The 
 greater the surface area of the particle the greater the amount 
 of water they hold in the films, or the greater amount of mineral 
 soup present for the plant hair rootlets to feed upon. This in- 
 creases also the rate of chemical solution, increasing the amount 
 of available plant food. A rock three feet cube exposes 54 square 
 feet of surface; divided into one-foot cubes, the surface area is 
 increased to 162 square feet; if broken into one-inch cubes it 
 presents nearly 2000 square feet to erosion and decay; if reduced 
 to bits one-twelfth of an inch cube, the square feet of surface is 
 increased to about 20,000 square feet, or nearly one-half an 
 acre in area. When we remember that in soil analysis in the 
 laboratory, the soil particles are actually separated and classified 
 into six fractions of a millameter, ranging from 1. to 0.005 in 
 diameter, and the percentage of each size obtained, it is evident 
 that the necessary information has been gained as to its value 
 as a feeding ground for crops. 
 
 The immense area exposed to the hair-like feeding roots of 
 plants by soils is shown in the following table which gives the 
 internal surface area of field soils in square feet. A cubic 
 
 foot of Square Feet 
 
 Coarse sand contains a surface area of 40,500 
 
 Medium sand 44,500 
 
 Sandy loam 66,600 
 
 Fine sandy loam 68,000 
 
 Silt loam 104,000 
 
 Clay loam 136,500 
 
 Clay 142,000 
 
 That is, the internal surface of the soil particles on a cubic foot 
 
Soil Particles 57 
 
 of clay represent a film surface of nearly three and a quarter 
 acres in area, or in other words one pound of coarse sand would 
 have about 400 square feet of surface, to 2000 square feet in 
 the case of clay. 
 
 SOIL SPACE. The space between the particles is also of 
 great importance in determining the circulation of water in the 
 soil and its capacity for retaining capillary water in the right 
 proportion for plant growth. This depends upon how the soil 
 particles are arranged independent of their size. The physical 
 properties of the soil depend upon this more than upon the chem- 
 ical composition. The physical properties in turn have a funda- 
 mental bearing upon the chemical and biologic properties of the 
 soil. The simplest arrangement would be that of spheres touch- 
 ing each other ; but such could be arranged in columnar order, 
 touching each other at four points, or in oblique order, each 
 touching one another at six points. If there are spheres of 
 diflferent sizes the small ones would rest in the spaces between 
 the larger ones so that the total voids or pore space would be 
 greatly reduced. This could be continued until the mass was 
 practically solid. Soil particles are, however, irregular in shape 
 and uneven in size, giving each soil an individuality in character. 
 
 TEXTURE. The size of the mineral particles determines the 
 soil texture, which influences alike the relation of moisture and 
 the chemical changes that take place through oxidation, especially 
 of the organic bodies in the soil. The texture determines to a 
 large extent the relative capacity of the soils to hold water. Under 
 equal conditions of depth and exposure coarse grained soils hold 
 less moisture and more air than fine grained soils, so that as a 
 whole they contain less soil solution, and consequently less nutrient 
 material available for the plants. They have generally a lower 
 absorptive capacity and permit more rapid oxidation. Another 
 important factor is the structure or the arrangement of the min- 
 eral matter. In some soils the mineral portions have a granulated 
 arrangement of flocculated masses, making the soil loose and 
 porous ; in others the grains exist in a compact form, making the 
 soil hard and compact. The adobe soils, for example, are hard 
 and compact, while sands are open and porous. Another factor 
 is the amount of humus or organic matter present, as it influences 
 not only the productive capacity of the soil but also its adaptation 
 to crops. The following table illustrates the effect of texture : 
 
58 Soils of California 
 
 Coarse sand containing- 4.8% of clay holds l.G'/o capillary moisture 
 
 Medium sandy loam " 7.3% " " 7.0% 
 
 Fine sandy loam " 12.6% " " 11.8% 
 
 Silt ■■ 10.6% '• " 12.9% 
 
 Silt loam ■• 17.7% " " 26.9% 
 
 Clay loam " 26.6% " " 32.4% 
 
 Clay •■ 59.8% " " 46.5% 
 
 POROSITY, There is always some unoccupied or pore space 
 or voids among the particles in all soils. If the particles are fine 
 the voids are small. If the particles are large the pore spaces are 
 large. A clay has more total pore space than sand, although 
 the individual spaces are much smaller in the clay. This rela- 
 tion between texture and pore space is shown by the following 
 table : 
 
 Percent Pore Space 
 by Volume 
 
 Clean sand contains 33.50 
 
 Coarse sand 40.00 
 
 Medium sand 41.80 
 
 Fine sand 44.10 
 
 Sandy loam 51.00 
 
 Fine sandy loam 50.00 
 
 Silt loam 53.00 
 
 Clay 54.00 
 
 Adobe 56.00 
 
 A porous soil i)ermits a freer circulation of the gases. The 
 porosity of a soil depends upon (1) the state of divisibility. (2) 
 upon the natural arrangement of tlie particles, and (3) upon the 
 voids, their size and arrangement. 
 
 SOLUBILITY OF THE SOIL MINERALS. The common 
 soil minerals mentioned in Part I are very slightly soluble, about 
 as much so as ordinary glass ; but in the finely divided state in 
 which they exist in the soil, an enormous surface is presenteii 
 upon which the film waters act, forming a soil solution which 
 contains the necessary amount of the mineral plant food ele- 
 ments. Twenty-five parts of potash and ten parts of phosphoric 
 acid per million of solution is ample for the needs of the plants ; 
 and the soil solution is said to be saturated when it contains 
 these amounts. 
 
 The degree of solubility of each mineral in the water in con- 
 nection with the mixture of so many kinds of minerals as are 
 found in the soils makes the concentration and composition of the 
 soil solution nearly the same for all soils. With 1,000,000 pounds 
 of water in contact with 5.000.000 pounds of soil the solution will 
 contain 25 pounds of dissolved potash, although the amount of 
 potash in the soil may vary from 30,000 pounds in one soil to 
 
Soil Particles 59 
 
 120,000 in another. As the 25 pounds of potash is gradually 
 removed from the film water by plants, more goes into solution, 
 so that no sensible change in concentration takes place in the film 
 water solution. 
 
 THE SOIL SOLUTION. The water in the soil absorbs 
 gases and takes up soluble mineral, animal, and vegetable matter 
 from the heterogenous mixture called the soil. The component 
 parts of the soil consist of mineral debris from rock decomposi- 
 tion, organic matter from the fermentation and decomposition 
 of former animal and plant tissue, carbon dioxide and other gases 
 from the air. and the products of the activities of myriads of bac- 
 teria, fungi, and enzymes. It is from this complex solution that 
 the plants, through their hair roots, draw all the material from 
 the soil that is involved in their growth, except that absorbed from 
 the atmosphere. It is well to remember here that after all only 
 about ten per cent of any vegetable growth comes from the soil 
 and that the remaining ninety per cent comes from the atmos- 
 phere. Burn a dried plant and the ash or mineral portion is 
 largely from the soil ; the carbon, hydrogen and oxygen that made 
 up the bulk of the plant came from the atmosphere. The study 
 of the soil solution and its relation to the soil and to plant growth 
 is of the highest importance, but belongs to agricultural chemistry 
 and to biology and not to the origin and classification of the soils. 
 So far as the mineral portion of the soil is concerned the concen- 
 tration of the minerals dissolved in the soil solution under normal 
 conditions is sufficient to support ordinary plant crops. Changes 
 in the concentration and proportion of the minerals dissolved 
 produce a rapid or a slower growth, and a greater or less total 
 growth, and dififerences in the character of the growth, such as 
 the tops growing faster than the roots, or the reverse. The soil 
 solution affects the physical character of the soil, for most dis- 
 solved substances affect the granulation or flocculation of the soil 
 particles. Magnesium, sodium and potassium chlorides and 
 sodium nitrate make the soil moist in dry weather by increasing 
 the surface tension of the soil solution. When this tension is in- 
 creased, water is drawn towards this point ; hence fertilizers may 
 assist in drawing water up in the soil. Oily substances do not go 
 into solution but spread in a film decreasing the surface tension 
 and diminishing capillarity. Some organic matters in solution 
 act the same as oil. 
 
60 Soils of Caxifobnia 
 
 PHYSICAL ABSORPTION, OR ADSORPTION. Soil par- 
 ticles attract and hold materials such as gases and dissolved salts 
 upon their surfaces. This is called absorption or adsorption and 
 is not to be confounded with chemical absorption. It varies with 
 the extent of surface exposed, and is greater in the fine textured 
 soils. This is an important factor in the retention of fertilizers. 
 This important property of the soils also tends to control the con- 
 centration of the soil solution and to prevent undue waste of 
 material. This adsorptive power varies greatly in different soils 
 and with different minerals, and varies for different substances 
 and parts of substances ; thus it is stronger for potash than it is 
 for chlorine, and will absorb potash from chloride of potash. Tt 
 is an important factor in regulating the concentration of the soil 
 solution. This action also purifies the waters passing through the 
 soil. If it were not for this property, wells would soon become 
 unwholesome from seepage. Soils absorb the gaseous products 
 of dead bodies and the products of the decomposition of animal 
 and vegetable matter. They withdraw and retain certain minerals 
 held in solution, as the sands along the seashore absorb the saline 
 matter so that quite pure water may be obtained by digging in the 
 sand some distance back from the water's edge. Soils absorb the 
 soluble minerals from fertilizers. If a soluble sulphate, chloride, 
 or nitrate of an alkali comes in contact with soil a part of the base 
 and none of the acid is withdrawn. Generally, however, there is 
 some other base in the soil that may join the liberated acid form- 
 ing new products, otherwise the acid leaches out. Soils also 
 absorb dissolved substances by mechanical inclusion or trapping 
 (imbibation) as a sponge; or a mineral such as Hme or ferric 
 oxide may absorb phosphoric acid, forming a new compound, as 
 lime or iron phosphate. Soils absorb potassium more readily 
 than sodium, magnesia than lime, and ammonia more than any 
 of these bases. More potassium is absorbed from the sulphate 
 than from the chloride of potassium. Clays especially absorb 
 potassium. Oxides of iron absorb potassium and ammonia. Soils 
 remove both the base and acids of soluble phosphates and silicates. 
 The nitrogen of insoluble organic bodies which nitrify slowly is 
 absorbed and retained ; but nitrate of soda is an exception and is 
 not absorbed, and is readily washed out of the soil. The absorp- 
 tive power depends upon the relative amounts of surface exposed 
 which depends upon the size of the particles, upon the kind of 
 surface acting, upon the concentration of the solutions, upon the 
 
Soil Particles 61 
 
 time of contact, and upon the temperature. The finer the par- 
 ticles the greater the surface and the greater the absorptive 
 power. The fine soils thus hold the plant food too closely to allow 
 rapid loss through drainage. Heavy soils containing hydrated 
 ferric oxide absorb bases more readily than the light soils. Soils 
 rich in humus are better absorbers than soils not so rich. The 
 absorptive power of soils is many times greater than it is ever 
 called upon to exert in sustaining field crops, or in fixing applied 
 fertilizers. An acre of soil nine inches deep could absorb nine 
 and a quarter tons of phosphoric acid, while 500 pounds is the 
 maximum for field crops. A soil can absorb twenty-seven times 
 as much potash as is called for, and thirty-two times as much 
 ammonia. During dry weather plants require a soil that is ab- 
 sorptive and retentive of water. The water absorbed by the roots 
 passes into plant circulation and must be evaporated by the leaves. 
 
 Pounds of 
 water 
 
 1 acre of wheat exhales 409,832 
 
 Clover 1,096,234 
 
 Sunflowers 12,585,994 
 
 Cabbage 5,049,194 
 
 Grape vines 730,733 
 
 Hops 4,445,021 
 
 Cultivation conserves the soil moisture. 
 
CHAPTER IX 
 SOIL MOISTURE 
 
 Soils var)- widely in their moisture contents. The supply is 
 determined by precipitation as rain or snow, by underground 
 seepage, and by irrigation. The soil moisture with its dissolved 
 substances forms the nutrient solution for the support of plants ; 
 yet water may exist in soils and not be available for nutrition. 
 Soils may contain water in different ways or conditions, each con- 
 dition exhibiting markedly different physical properties and pecu- 
 liarities. The water present may be (1) gravitational water, (2) 
 capillary water. (3) hygroscopic water, (4) chemically combined 
 water or water of hydration, and (5) as film water. 
 GRAVITATIONAL WATER. This is water that is free to 
 move through the soil under tlie influence of gravity. It is water 
 present in excess of the amount which the soil is able to retain 
 and which is free to drain away, and depends upon the maximum 
 capacity of the soil to hold water. This retentive capacity of the 
 soil varies according to the physical properties. Plants suffer 
 much more quickly from drought on sand where the retentive 
 capacity is small, than on clay where the retentive capacity is 
 large, even when the soils are equally wet at the outset. The 
 drainage features of the soil control the amount of gravitational 
 water retained ; the amount of excess salts held in solution ; and 
 often materially influence the organic constituents, the aeration, 
 and the oxidation of the soil. Artificial drainage gives greater 
 depth to the working soil, warms the soil, admits air, increases 
 the amount of plant food, lengthens the growing season, improves 
 the texture, increases the porosity, and prevents waste through 
 heavy washing. 
 
 CAPILLARY WATER is that which is retained in the capil- 
 lary spaces in spite of gravity, and which is capable of movement 
 under capillary conditions. The capillary capacity of a soil de- 
 I)ends upon (1) the texture of the soil, (2) upon the structure, 
 (3) and upon the organic content. The capillary water is the 
 principle source of water and mineral plant food to the plants, 
 and is probably the seat of important chemical and biologic 
 
Soil Moisture 63 
 
 changes in the soil. The relative amount of capillary water de- 
 pends upon the texture, the depth of the soil, drainage, and the 
 amount of organic matter present. The best amounts of capil- 
 lary water, called the optimum amount, varies with each soil, 
 ranging from twenty per cent of the weight of dry clay soil to 
 four per cent for some sandy soils. 
 
 Capillary movement may take place upward, downward or 
 laterally. After a rain, when the surface of the soil is more 
 moist than that below, capillary action aids gravity and hastens 
 the penetration of the water downward, but as soon as the surface 
 soil becomes the dryer the capillary flow is upward. Where plants 
 are growing the movement is towards the roots from all sides 
 where the soil has more water than in the vicinity of the roots. 
 The rate of the capillary movement varies with the distance the 
 water must be moved and the character of the pore spaces through 
 which the water must move. For fine sands the rate by experi- 
 ment was 2.37 pounds per square foot per day of 24 hours, and 
 for clay loam was 2.05 pounds. When the soil becomes nearly 
 air dry to any considerable depth the pore space becomes filled 
 with air and this must be expelled before water can enter. In 
 some sandy soils the air spaces are large, the air readily dis- 
 placed, and the soil easily moistened. In fine soils a moderate 
 shower fills up the surface pores at once and prevents the escape 
 of the soil air, and this prevents the entrance of the water to any 
 depth. Clays especially remain dry below even when the surface 
 is eroded by heavy rains or irrigation. On such soils time must 
 be taken to let the water soak in slowly, gradually displacing the 
 air from the fine pores of the soil. 
 
 WATER VAPOR. Even when the soil contains neither 
 gravitational or capillary water the air that fills the pores or voids 
 contains water vapor that is important in plant nourishment. 
 
 HYGROSCOPIC WATER, or moisture, is that which con- 
 denses from the air on the surface of the soil particles when the 
 soil is allowed to become air-dry. It is found on the surface of 
 the grains and is not capable of movement by gravity or capillar- 
 ity. The hygroscopic moisture adheres to an air-dried soil and 
 undoubtedly plays an important part in the chemical changes 
 which take place. Under ordinary climatic conditions loams and 
 clays contain as much as four to eight per cent of their weight 
 
64 Soils of Califobnia 
 
 of hygroscopic moisture, and soils rich in organic matter contain 
 even more. 
 
 Sands have Httle power of retaining water and all added 
 water flows at once to lower levels and the amount held by 
 capillarity is far less than in soils composed of finer materials 
 such as silt and clay, but they can retain considerable hygroscopic 
 moisture. 
 
 WATER OF HYDRATION. This is the water chemically 
 combined with the minerals and is of little use directly to the 
 plants in humid climates ; but in arid climates certain desert plants 
 avail themselves of water from this source, dehydrating the mate- 
 rials. This water is also known as the zvater of crystallisation. 
 Thus, gypsum is sulphate of lime (CaS04) plus (2H2O) two 
 molecules of water; or in other words, 100 pounds of common 
 land plaster or gypsum is really 79.1 pounds of sulphate of lime 
 and 20.9 pounds of water. When the gypsum is burned the water 
 of crystalHzation is driven off and "plaster of paris" is left. Other 
 minerals contain water of crystallization, as glauber salts (sul- 
 phate of soda), borax, etc. 
 
 FILM WATER. This is the most important form in which 
 water exists in soils, yet little attention has been given it until 
 recently. Drop a marble into mercury and it comes out dry. Lift 
 it from water and it carries a film of water over its entire surface 
 due to the attraction of the marble for water, or adhesion. The 
 film is thick on account of the attraction of the particles of water 
 for each other, or cohesion. 
 
 Soils must be moist or plants will not grow, but this water 
 does not fill the spaces in the soil proper ; it sticks to the grains 
 covering them with a thin film while the air fills the spaces be- 
 tween the particles. It clings so closely that it cannot be rubbed 
 off and is not easily driven off except by heats greater than that 
 to which soils are naturally subjected. 
 
 The very driest road dust has some film water clinging to it. 
 It is the film water that is the feeding ground of the plants, the 
 mineral soup that nourishes them. The hair-like rootlets, some 
 of them only three-hundredths of an inch in diameter, must come 
 into intimate contact with the film of moisture, without being 
 excluded from the air supply which promotes their growth. The 
 right amount of film moisture and air in the air spaces is the key 
 to success in modern agriculture. The chemistry and physics of 
 
Soil Moisture 65 
 
 the film moisture is one of the most interesting studies in agricul- 
 tural chemistry. The Bureau of Soils has discovered that there 
 is a pressure on the surface of a mineral particle moistened with 
 water, acting at an inconceivably small distance from the solid 
 surface, which is estimated as at least 10,000 atmospheres, or 
 150,000 pounds per square inch, or fifteen times the muzzle pres- 
 sure of a 12-inch gun. Under this pressure the concentration of 
 the solution is enormously increased in the surface film on the soil 
 particle, and chemical changes and reactions may take place there 
 which are impossible to duplicate in the chemist's laboratory. 
 Each root is at first a slender thread-Hke object which extends 
 itself through the voids in the soil. When it obtains lodgment on 
 a particle it rapidly increases in size and vigor. From a slender 
 fiber of microscopic size, less than the 1/300 of an inch in 
 diameter, it may increase to a foot or more across. These root- 
 lets spread like an octopus through the soil, feeding on the film 
 waters and soil solution. They are always moving, absorbing and 
 excreting water and dissolved substances, and ever pushing for- 
 ward. When they die they contribute their organic matter to the 
 soil and their decay leaves channels through the soil facilitating 
 drainage and aeration. 
 
 CRITICAL MOISTURE CONTENT. The amount of water 
 available at which the plants are just able to survive is termed 
 the minimum or critical moisture content; the highest per cent at 
 which the plant will survive is the maximum moisture content; 
 and the intermediate point at which any crop makes its best 
 growth is the optimum moisture content. Each of these points, 
 or moisture conditions, is very definite for each soil and each 
 crop. The maximum and minimum points are marked by distinct 
 changes in (1) the cohesion of the soil, (2) in the volume weight 
 of the soil, and (3) in the freedom with which the soil gives up 
 its moisture. Between the maximum and minimum the soil 
 works the best; it does not puddle, gives the desired granulation, 
 known as good tilth, and the clods are not hard, and the ground 
 is easily pulverized. 
 
 The maximum water capacity is the total amount of water 
 which can be put into a given volume of soil. It depends upon 
 the total pore space of the soil. The following shows the amount 
 of water present in some soils at the saturation point : 
 
66 Soils of California 
 
 Percent at 
 Saturation 
 
 Dunesand 40.5 
 
 Coarse sand 39.5 
 
 Fine sandy loam 38.0 
 
 Light silt loam 38.0 
 
 Clay 54.5 
 
 Humus 333.3 
 
 A saturated condition of the soil is unfavorable to agriculture, 
 except to the swamp types such as rice and cranberries. The 
 gravitational water must be removed by natural or artificial drain- 
 age for other crops to grow, as its presence in the root zone is 
 injurious to most farm crops. 
 
 EVAPORATION. The sun is the greatest of all pumps, and 
 the rate of evaporation for any soil is important. It is relatively 
 rapid above the optimum amount of moisture, and very much 
 slower below that point, and to a large extent takes place within 
 the soil instead of from the surface, the vapor coming out 
 through the slow process of diffusion. A dry surface mulch con- 
 serves the moisture below by protecting from surface evapora- 
 tion, as the capillary movement of water in the dry mulch is 
 exceedingly slow. The waters in the lower layers can loose only 
 by being raised to the surface by capillary action. This is the 
 fundamental secret of dry farming. Evaporation is affected also 
 by the attitude of the soil, being greater where the soil is exposed 
 to the direct heat of the sun, and less in shaded places. 
 
 WATER TABLE. The point at which water stands in soil 
 is called the zvater table. If it is only two or three feet from 
 the surface there is not enough dry soil for the roots to grow 
 in and they drown. Such soils are said to be shallow. If it is 
 too deep, water does not rise from it by capillary attraction and 
 the plants suffer from drought. The height of the water table 
 depends upon the texture of the soil, the character of the sub- 
 soil, the presence or absence of hardpan, natural or artificial 
 drainage, etc. If a well is sunk eighty feet and fills up with 
 water to within fifteen feet of the surface, it means that the 
 ground is full of water to that level. This level is known as the 
 ground zvater level, ground zvater surface, or zvater table. During 
 wet weather the water table rises, and in periods of drought it 
 sinks. In lakes, marshes and streams the water table stands at 
 the surface. It is never at rest, rising or falling and moving in 
 slow currents through porous rocks and rapidly in joints and 
 cracks and underground channels. It is the source of springs, 
 
Soil Moisture 67 
 
 and is important in extending the process of weathering and rock 
 decay below the subsoil and deep into the bedrock. A fluctuating 
 water table permits roots to develop during one season at a certain 
 depth, and then by a rise or fall of the ground water either 
 drowns them or leaves them thirsty. The condition of the water 
 level should always be studied in connection with all soils before 
 planting anything, and the method of irrigating and the amount 
 of water used should be regulated accordingly. In one part of 
 this state v/hen irrigation began, the water table was from seventy 
 to one hundred and fifty feet down; now it is from ten feet to 
 surface level. This shows great waste of water in some manner. 
 All water that passes below the depth of root penetration is not 
 only lost to all good at the point applied but may be a serious 
 menace to land lying lower. Why waste water by soaking the 
 ground when the plants feed upon all moisture except gravita- 
 tional water? 
 
 The ideal way would be to copy nature and irrigate with a 
 spray falling like rain, giving the ground only what it needs for 
 film and capillary water and leaving the needed amount of air in 
 the voids, and protecting the water from evaporation by keeping 
 the surface in good tilth by cultivation, or by mulching. When 
 this is done, then the irrigation waters of the state will be con- 
 served and extended to several times the amount of land they 
 are now used for. 
 
CHAPTER X 
 VARIOUS DEFINITIONS 
 
 Soils become sticky or plastic, when mixed with water, and 
 this property is termed plasticity. In general, the finer the soil 
 the greater the plasticity, as in the finer textured clays. Sandy 
 soils possess it to some extent, however, for this material adheres 
 when wet but falls apart on drying, while clay soils become hard 
 on drying. The plasticity of a soil afifects its cultivation and 
 drainage. 
 
 Some soils expand on wetting and shrink on drying. This 
 is called checking. In a clay soil the surface film draws closer 
 about the particles as the water dries out, and moves the particles 
 closer together. As the mass does not move as a whole, cracks 
 or checks are developed. Very pure clay when dried contracts 
 18.3 per cent of its original volume, sandy clay 6 per cent, and 
 muck 20 per cent. The finer the texture the greater the shrinkage. 
 When large checks or cracks are formed, the roots of plants 
 may be broken, or at least injured, the soil dries out to greater 
 depths than from surface evaporation, and the advance of root- 
 lets is interfered wnth. 
 
 Small particles of soil, according to the moisture conditions, 
 may adhere to a large one, or a number of small particles may 
 adhere toegther in a group. This structure is called granular, 
 or crumb structure, when the aggregate of particles is not large 
 and readily fall apart. When the group reaches a large size and 
 interferes with cultivation they are called clods. 
 
 Dissolved salts, such as lime, oxides of iron, and silica, may 
 be drawn to the surface when the soil is moist, and on drying may 
 bind or cement the surfaces together, making the fully dried soil 
 much harder than when moist. Some of the red soils of the 
 coastal plains show a tendency to case harden at the surface, an 
 action due to the iron compound present. See hard pan, described 
 elsewhere. 
 
 SOIL ATMOSPHERE. Plants must have air to breathe and 
 need a well- ventilated soil as a rule. The oxygen of the atmos- 
 phere penetrates to a great depth, and acts especially upon tlie 
 
Various Definitions 69 
 
 lower oxides of iron, converting them into peroxides and pro- 
 moting decay. The soil atmosphere contains less oxygen and is 
 considerably richer in carbonic dioxide and nitrogen than the air 
 above the surface. The diffusion of air through soil is slow, and 
 cultivation is necessary with most crops in order to secure more 
 perfect aeration. Unless air freely enters the soil and is fre- 
 quently changed, or, in other words, unless the soil is well ven- 
 tilated, nitrification cannot go on. Hence the necessity for plow- 
 ing, spading, raking, and stirring the soil by the various methods 
 of cultivation. The air drawn into the soil aids the roots in as- 
 similating plant food. Few vegetables or trees tolerate having 
 their roots permanently bathed in water during the growing sea- 
 son, any more than a human being can keep well if his shoes 
 and stockings are constantly wet. A few species of trees like 
 the bald cypress {Taxodium disfichnm) accommodate themselves 
 to permanently wet earth by processes from their roots which 
 bring air to them ; but this is living like a diver, who is dependent 
 upon the air tube that connects him with the necessary atmosphere 
 above. 
 
 Gravity, cohesion, and other forces tend to bring the soil 
 j)articles too close together, giving the soil a compactness that is 
 undesirable. Water and air will not penetrate a soil that is 
 packed too close. When a soil is plowed, air is brought into 
 direct contact with particles that had been previously shut away 
 from it. Plowing and other methods of cultivation are chiefly 
 beneficial because of their effect upon soil ventilation. Heavy 
 soils need more cultivation and more thorough cultivation than 
 light soils. The purpose of cultivation is to break up and fine 
 the soil more than it is to keep down the weeds ; to admit air into 
 the soil and to form mulches to check the evaporation of the 
 capillary and film waters. 
 
 The aeration of the soil and the structure and arrangement 
 of the particles is improved by alternating deep rooted and shal- 
 low rooted crops, just as it is improved by alternating deep 
 plowing with shallow ploughing. 
 
 SOIL TEMPERATURE. Soils must be warm in order to 
 produce crops. The colder the soil the slower the seeds ger- 
 minate. Crops differ in this respect, for the temperature favor- 
 able for the germination of barley is 70 degrees F., clover 7? 
 to 100, pumpkins and tomatoes 100. Onions, barley, turnips, 
 
70 Soils of California 
 
 parsnips, peas, and potatoes are cool plants and can be planted 
 when the ground is cold ; tomatoes, melons, squashes, etc., are 
 hot plants that do not grow until the soil is thoroughly warm. 
 
 The sun is the furnace that heats the soil, and this heat is 
 subject to seasonal and hourly variation. The temperature of the 
 soil depends upon (1) the heat supply, (2) upon the specific 
 gravity of the soil, (3) upon the specific heat of the soil, (4) 
 upon the color, (5) upon the attitude or location, as on a north 
 or south slope. (6) upon the conductivity of the soil particles, 
 (7) upon the circulation of the air in the soil, and (8) upon the 
 character of the water content. The specific gravity of the soil 
 afifects the temperature, for the larger the mass is in relation 
 to weight, the more heat required to change its temperature ; the 
 more dense the soil, the more heat is absorbed by each layer, and 
 the more rapidly the heat is conducted through the mass. The 
 conductivity of the soil for heat depends upon ( 1 ) composition, 
 (2) texture, (3) structure, and (4) moisture content. The 
 coarser the structure the greater the conductivity. A compact 
 soil conducts heat more rapidly than a loose one and gives it off 
 more readily. The coarser the soil the warmer it gets and the 
 better it holds the heat ; hence gravelly and sandy loams are 
 among the earliest and warmest of soils. A clay, however, warms 
 faster than sand, for the particles lie closer together and the heat 
 passes more readily from particle to particle, and a clay soil 
 loses heat faster than a sand for the same reason. A clay soil 
 holds more water and loses more heat through the larger evapora- 
 tion ; hence sandy soils are warm and clay soils are cold. Drain- 
 ing a soil warms it. Dark soils absorb more heat and are VN-armer 
 and earlier than a light colored soil. Uneven and ridged soil 
 loses more heat than a smooth level soil. The presence of small 
 stones and pebbles make a soil more porous and warmer; hence 
 gravelly and sandy soils are the warmest and earliest soils. Clay 
 warms faster than sand, but it also loses heat faster. A smooth 
 surface absorbs heat more than a rough or rigid one. The "lay 
 of the land" or attitude of the soil has an important influence 
 upon temperature. A northern slope that receives only one 
 third of the sunshine that the same kind of soil receives on a 
 southern slope may be seven to ten degrees cooler in summer than 
 the soil of the southern slope, while the soil with the southern 
 attitude may be from three to five degrees warmer than the same 
 
Vabious Definitions 71 
 
 soil on the level land lower down, the rays of sunshine striking \l 
 at right angles while they strike the level land obliquely. 
 
 Chemical changes in the soil are hastened by a high temper- 
 ature and retarded by a low temperature. For example, barn 
 fertilizers lie dormant in the soil through fall and winter and 
 become active under the heat and moisture of the spring. A 
 lumpy soil is cold either because of the lack of humus, or 
 through excessive moisture, and its available feeding ground is 
 also greatly reduced. Frozen soil means a complete suspension 
 of chemical and vital action but not of mechanical. Everyone 
 has noticed the "heaving effect" of ice, how fence posts are 
 raised, and stones are lifted by frozen ground through the ex- 
 pansion of water when it freezes. Soils are pulverized, broken, 
 heaved, and improved by freezing. It aids in the decay of the 
 mineral matter and fines the soil. 
 
 ELECTRICITY. Weak currents of electricity are effective 
 in plant growth, and are being utilized in intensive cultivation. 
 They stimulate in some cases the activity of bacteria, and pro- 
 mote chemical activity in the soil solution. It is not yet known 
 what effect they have upon the physical condition of the soil. 
 
 DESCRIPTIVE TERMS. Common descriptive terms are 
 applied to soils to designate certain definite properties. When 
 one speaks of a soil as fine, coarse, cold, warm, light, or heavy, 
 he should use these words with precision, and as having relation 
 to definite properties of the soil, and not use them carelessly or 
 loosely. 
 
 Other things being equal, the finer the particles of the soil 
 the richer it is, because it contains more internal surface for the 
 roots to feed upon, as the film water upon the outside of these 
 fine soil grains is their feeding ground. The absolute weight of 
 a soil depends upon its absolute specific gravity and the volume 
 of pore spaces in the mass. The average specific gravity of soil 
 material is 2.65. The following table shows the comparative 
 absolute weights of some soils: 
 
 Specific Weight per cubic foot Weight per 
 
 Gravit. Kilos. Pounds acre foot 
 
 Coarse sand 1.60 45.5 100.0 4,356,000 
 
 Medium sand 1.54 43.5 96.0 4,200,000 
 
 Fine sand 1.48 42.0 93.0 4,080,000 
 
 Sandy loam 1.30 36.8 81.0 3,550,000 
 
 Fine sandy loam 1.32 37.4 82.5 3,590,000 
 
 Silt loam 1.24 35.2 77.5 3,400,000 
 
 Clay 1.17 33.1 72.6 3.180.000 
 
72 Soils of California 
 
 It is seen that the finer the soil the hghter its absolute weight. 
 Clay soils may range from 60 to 90 pounds in absolute weight, 
 according to their fineness and state of granuation, while sand 
 soils may weigh from 90 to 110 pounds per cubic foot. The terms 
 light soil and heavy soil as used in agriculture have absolutely 
 no reference at all to the actual or absolute weight of the soil, 
 but solely to the amount of force required in tilling the land. Thus 
 a sandy soil is light because it is easy to cultivate, as the particles 
 move easily. Clays are heavy because the particles stick together, 
 and the plow and other tools drag heavily. 
 
 The most obvious physical properties of a soil are its tex- 
 ture and color, both of whicii indicate important differences that 
 influence crops. The texture is determined by the proportion oi 
 the different sized mineral particles it contains. This proportion 
 is ascertained by actual physical analysis and is the basis of soil 
 classification. The soil is washed in water in appropriate ma- 
 chinery and the fine and coarser materials separated by centri- 
 fugal machines. Some of the coarser particles may be separated 
 by sieves. In this way the soil is separated into fine gravel, coarse 
 sand, medium sand, fine sand, very fine sand, silt, and clay, and 
 the percentages of each present in the soil determine its texture. 
 A high per cent of gravel and coarse sand give a coarse texture, 
 as a high per cent of very fine sand, silt or clay will give a fine tex- 
 ture. 
 
 COLOR. There is no longer any doubt but that the color of 
 a soil is important. It indicates some associated properties, caus- 
 ing the color, which influences the yield and quality of the crop. 
 What the colors of the California soils indicate is brought out in 
 the individual descriptions of the soils in Part 4. Just why the 
 color should indicate certain qualities is not always apparent. The 
 color of a soil is not. as a rule, the color of the individual par- 
 ticles, but of material which adheres to the particles. Iron com- 
 pounds give rise to red, yellow, blue and gray colors ; organic 
 matter to blacks and browns, and their combination with iron salts 
 give various intermediate tints and shades. 
 
 In the boulder clays of glacial regions, a bluish color is com- 
 mon, due to the presence of protoxide of iron (FeO) resulting 
 from a deficiency of oxygen. Where this comes in contact with 
 carbonated waters, carbonate of iron is formed and the soil is 
 gray ; where there is an abundance of oxygen the iron becomes 
 
Various Definitions 73 
 
 the sesquioxide (FcaOg) or "iron rust," which has a deep red 
 color. Iron quartz sands and residual shale soils have colors due 
 to the color of the mass of the particles themselves. 
 
 A dark colored soil absorbs heat much more rapidly than does 
 a light colored one, and therefore warms up faster. A dark col- 
 ored soil is generally regarded as a fertile soil. Where this is 
 due to the presence of organic matter this is true, but it is not 
 always a reliable guide, as other properties of the soil must be 
 taken into consideration, such as the climate, altitude, composi- 
 tion, etc. The color of a soil is a valuable guide to the person 
 experienced in the climatic conditions of the given region, as it 
 points out the condition and productiveness of the soil ; but one 
 versed in productiveness as related to color in the humid regions 
 of the east is all at sea when he first looks at the soils of the arid 
 and semi-arid regions of the west. A mottled and uneven color 
 may indicate poor aeration which is due to poor drainage. "Rich 
 black soils" have been favorites in the humid regions from the 
 dawn of history, while brownish soils on low ground were be- 
 lieved to indicate acid humus or sour lands ; but in the forest such 
 colors would indicate decayed wood. Black soils on the upland 
 prairies of the east often indicate a full supply of lime carbonate 
 and a highly productive soil. Some red soils of the southwest 
 are called "mahogany soils" and are considered prizes, but red 
 soils produced from iron bearing sandstones are often very poor 
 soils whether found in the foothills of the Sierras or in the cot- 
 ton states of the south. 
 
 A red soil is apt to be well drained, for the iron rust, or fer- 
 ric hydrate, cannot exist in badly drained soils. White soils with- 
 in the tracts of red lands may show a watery maceration that is 
 injurious. Ferric hydrate has a high power of absorbing gases 
 from the atmosphere, standing next to humus in this respect, 
 while like humus it renders heavy clay soils more readily tilled. 
 The red tint absorbs heat readily, giving a warmer soil, appreciat- 
 ed by orchards and vineyards. Yellow soils owe their tint to 
 the smaller amount of ferric hydrate and share to less degree in 
 its advantages. White soils and light gray soils are regarded with 
 disfavor in the humid regions as meaning a scarcity of both humus 
 and ferric hydrate through the action of stagnant water, and in 
 some localities they are known as "crawfish soils," as they are 
 often inhabited by crawfish, whose holes reach water in a short 
 distance. 
 
74 Soils of California 
 
 In the west and in arid regions generally, white and light 
 gray tints are very common characteristics of the very best soils. 
 They are rich in plant foods ready for use and not affected yet 
 by water. This does not refer to the white alkali spots which 
 are described under the head of alkali elsewhere. 
 
 SOIL ODORS. When soil has been recently wet it emits a 
 peculiar odor which is not disagreeable. This odor comes from 
 a neutral organic compound of what the chemist calls the aromatic 
 family. The odor is generally penetrating, almost piquant, and 
 analagous to the camphorated bodies. It amounts only to a few 
 millionths of a per cent and is of little value in most cases in de- 
 termining the crop value of a soil. 
 
 FERTILITY. The fertility of the soil was for many decades 
 believed to be dependent mainly upon its chemical composition as 
 tabulated in the old form of chemical analysis, and older works 
 are filled with tables of chemical analysis that are now known to 
 be worthless. 
 
 In spite of the tonnage of books on the subject of fertilizers, 
 and fertility, the actual knowledge of fertilizers is still very 
 meager and almost entirely empirical. The chemical analysis of 
 a soil still fails to explain its relative productivity. Chemical 
 analysis still fails to determine the amount of fertilizers needed 
 by lands. 
 
 Mineral fertilizers have however a decided influence upon 
 the physical character of the soil, which is really of greater im- 
 portance than its character as given by chemical analysis. Fer- 
 tilizers readily affect the granulation of the soils, and all the prop- 
 erties dependent upon that, often correct acidity, increase the per- 
 meability of the soil and stimulate diffusion. They furnish heat 
 that may stimulate the dormant spores of some bacteria into life 
 and activity. Fertilizers must be finely (Hvided and used on well 
 aerated soil. The phosphates that are insoluble in water are 
 slowly dissolved by the acid sap of the root hairs, but largely re- 
 main inert. Bones decompose in clay soil so slowly as to be of 
 little value. Organic fertilizers such as oil cake, bones, and farm- 
 yard, yield only a small portion of their nitrogen during the 
 first year. 
 
 The old soil analysis made by extracting the soluble por- 
 tions with acid and giving the results as soluble and insoluble 
 are now known to be worthless and to mean nothing. A soil 
 
Okganic Matter ix Soil 75 
 
 which is utterly barren under certain conditions of cHmate or 
 moisture may under changed conditions — not changed composition 
 — become fruitful in the extreme. All of the citrus regions of 
 California are an illustration of this fact. It has been repeatedly 
 demonstrated in this state, where dreary stretches of aridity given 
 over to sand, sage brush and clay, have been converted into the 
 richest of orange groves and vineyards. 
 
 If the arrangement of the soil particles is favorable to root 
 action and conservation of moisture, the soil may be made fertile 
 by proper water, and by proper treatment, and is therefore 
 adapted to certain crops. A soil containing too large a propor- 
 tion of iine clay may have too large a proportion of moisture so 
 as to be unsuited to cultivation when saturated and become 
 equally unfit by induration when dry, calling for the admixture 
 of sands to give it a loamy character. A light, porous soil may 
 be fertile when watered, but parts with its moisture so readily 
 as to be barren if subjected to drought, and is benefited by the 
 admixture of some heavier soil. The capacity of a soil to care 
 for the water it receives is the most important of its properties. 
 The fertility of the soil is largely influenced by the cultivation it 
 has received, and by the toxins left by the previous cropping, as 
 all crops leave the soil in a more or less unsanitary condition. 
 "Snow is the poor man's fertilizer," because it heaves, breaks up, 
 loosens, and otherwise changes the physical condition of the soil. 
 
CHAPTER XI 
 ORGANIC MATTER IN SOIL 
 
 Almost every soil contains plant remains. Forest soil con- 
 tains decayed leaves and stems, sod land is filled with fine roots, 
 and low swampy areas are full of dark organic material. The 
 organic material of soil consists in general of the tissue remains 
 of plants and to a less extent of animals, numerous products 
 of bacterial origin, secretions of algae, fungi, etc., etc. Plants 
 are the chief source of the organic matter, the material going to 
 decay through the action of bacteria and fungi in addition to the 
 purely chemical changes. The chemical composition of the or- 
 ganic matter is as variable as the materials from wihch it is de- 
 rived and the conditions under which it is formed. Many of 
 these are acid, some act as bases (as ammonia and marsh gas). 
 They react with each other in many ways, but more especially 
 they react with the mineral elements of the soil, forming plant 
 foods, and releasing food elements from the mineral combinations. 
 Nitrogen, which is not a constituent of the rocks, is made avail- 
 able through this organic decay. The percentage of nitrogen 
 varies greatly, some humid soils containing less than two per cent, 
 while some soils of the arid regions contain over twenty-two 
 per cent. Under cultivation the nitrogen in the organic matter 
 is changed to forms available to plants. The organic substances 
 are greater in the soil than in the subsoil, decreasing with depth. 
 Arid soils generally contain less organic matter than the soils of 
 humid regions, and the soils of cold climates contain more than 
 those of the warm climates. Wet soil contains more than dry 
 ones, and clay soils more than sandy ones. Vegetable matter 
 after life is extinguished undergoes complete decay which returns 
 all its matter to dust or gas. This is largely done by bacteria 
 which return the material to a soluble state and is dissolved by the 
 soil solution and becomes food for plants. 
 
 Owing to its weak plasticity and great contraction when dried, 
 organic matter hastens the granulation process in clay soils. It 
 binds together and imparts a loamy character to light sandy soils, 
 preventing drifting by the wind and erosion by the rain. It in- 
 
Obganic Matter in Soil 77 
 
 creases the moisture-holding capacity of a soil and improves its 
 power to resist drought. It makes soils warmer by darkening the 
 color and thus increasing their absorption of the heat of the sun. 
 It provides plant food direct, and releases plant food in the soil 
 minerals. Plant roots not only contribute organic matter to the 
 soil but on decay leave openings which aid drainage and aeration. 
 The color of the soil is not, as often supposed, a safe guide to 
 the percentage of organic matter present. Some red, yellow, and 
 brown soils have more organic matter than some black soils and 
 are more fertile. This is notably true on the Pacific Coast, more 
 so than in the east. 
 
 TOXIC BODIES. Plants produce waste bodies which may 
 become harmful or toxic to themselves and to other plants of 
 allied species, unless removed or changed in character in the soil. 
 The incompatibility of weeds and crops, of grass and trees, is 
 due to the excretion of one plant inhibiting the growth of the 
 other. The fact that some varieties of plants are not afifected 
 by or even destroy the excreta of other plants is the explanation 
 of the beneficial results obtained by the rotation of crops. A pure 
 crystalline body has been obtained, for example, from a cowpea- 
 sick soil, that was not present in the soil before cropping, which 
 is exceedingly toxic to cowpeas when mixed in otherwise good 
 culture medium, but this same substance is not toxic to wheat. 
 These toxic bodies are fatty, nitrogenous or non-nitrogenous or- 
 ganic bodies, unstable and changing rather easily by oxidation 
 into harmless or even beneficial bodies. Bacteria aid in their 
 oxidation or reduction. They are especially apt to form where 
 the aeration is deficient in the soil, as in an overwet soil, and are 
 benefited by better aeration by means of thorough underd raining. 
 Cultivation, if not so deep as to stir up the subsoil, tends to hasten 
 oxidation and the destruction of these bodies. The necessity for 
 guarding against toxic bodies is shown by such experiences as 
 these. Peat soils have given over 400 bushels of potatoes the 
 first year, but in two or three years the yield has dropped to 
 about 40 bushels per acre, although the fertility as regards barley 
 was not noticeably affected. Flax cannot be maintained for more 
 than two or three years continuously, yet the flax-sick soil is not 
 sensibly injured for producing wheat and other crops.. Such soils 
 are not worn out, but are sick, poisoned by the excreta from the 
 crops. The best way to avoid this poisoning of soils by toxins 
 
78 Soils of California 
 
 is to avoid the continual growing of a crop in the presence of its 
 own excreta, products of decay, etc., or, in other words, by the 
 rotation of crops. 
 
 LIFE IN THE SOIL. A fertile soil fairly hums with activ- 
 ity. Myriads of forms of life are at work, changing, breaking 
 down, building up. Some are beneficial, some harmful, and some 
 simply neutral or harmless. A vast number of animal and vege- 
 table organisms live in the soil, giving it a flora and fauna scarce- 
 ly less complex than that which appears above the surface. Soils 
 in which crops grow have been formed by rock decay and plant 
 growth. The mineral portion comes direct from the rock, the 
 humus and other organic constituents have come from living 
 bodies, most of them of microscopic size. The greatest scaven- 
 gers of the soil are those bacteria that work over and change re- 
 mains of plants and animals. Some of these change and purify 
 the soil while the crop is growing and after the crop is harvested. 
 Other forms of bacteria bring about the production of substances 
 very toxic to plants. 
 
 Bacteria are intimately associated with many of the normal 
 processes going on in the soil and soil solution. They are the 
 most important of all the microscopic forms of vegetable life, 
 for the growth of the higher food plants is absolutely dependent 
 upon their presence. They have many functions, the most import- 
 ant one being that of making soluble the material used as food 
 by the higher plants. They are transformers, not producers, of 
 the fertility in the soil, for they add no plant food but render 
 available that which is already there. The success of agriculture 
 depends largely upon the regulation of the growth of bacteria, for 
 without them the soil would yield no crop. The relation of the 
 soil to crop production involves the growth of these low forms of 
 vegetable life, and the most successful farmer is the one who 
 consciously or unconsciously secures the best conditions for their 
 growth. These minute plant organisms remove dead animals and 
 plants from the soil by decomposition, fermentation, etc., produc- 
 ing the so-called self-purification of the soils. Without them the 
 soil would soon be clogged with the remains of past animals and 
 plants. 
 
 KINDS OF BACTERIA. There are a number of excellent 
 works on agricultural bacteriology^ and it is not necessary to go 
 into details of their structure and classification; but onlv to note 
 
Organic Matter in Soil 79 
 
 in a general way their relation to soils and soil building. Bac- 
 teria may be divided into two classes, those that are beneficial to 
 food plants and those that are injurious. They are exceedingly 
 minute, some being so small that 25,000 laid side by side would 
 only occupy a line an inch long. A single drop of milk may con- 
 tain 100,000,000. They multiply with extreme rapidity, a single 
 bacterium if unchecked could increase to 17,000,000 of offspring 
 in twenty-four hours, and in five days of unchecked reproduction 
 of all the descendants, could fill the oceans. This fecundity is 
 however checked by lack of food and by the poisons they secrete 
 killing themselves. The round forms are called micrococcus, the 
 cylindrical bacillus, the curved vibrio, spirilli, etc. They are min- 
 ute unicellular vegetable organisms multiplying generally by di- 
 vision of the cell, but some also multiply by spores which can 
 endure prolonged drying and extreme cold. Those that flourish 
 only in an abundant supply of oxygen are called aerobic; those 
 that require little or no oxygen are called anaerobic. The aerobic 
 forms are generally beneficial to agriculture, while the anaerobic 
 are generally injurious. Their names and kinds are already legion 
 in number, and each seems to have its own work to do, and its 
 own chosen field to work in, and to act its part in the intention, 
 purpose and design of the Universe. 
 
 The bacillus mycoidcs occurs constantly in surface soils and 
 is present in natural waters and is one of the most active of the 
 ammonia makers. The beggiatoa or sewage fungus reduces sul- 
 phates with the evolution of hydrogen sulphide and the depositing 
 of free sulphur within their cells. The saccharomycctes or yeasts 
 derive nitrogen from organic substances and salts of ammonia 
 and carbon from organic matter. The food of the bacteria con- 
 sists of organic matter with certain necessary minerals. These 
 minerals are phosphoric acid, potash, and lime. The presence 
 of oxygen is necessary. When it is absent or reduced to a low 
 percentage the nitrification of the soil by bacteria stops. A base 
 with which the nitrous or nitric acid formed may unite is neces- 
 sary, such as carbonate of lime or a small per cent of alkali. An 
 excess of alkah prevents nitrification of the soil. A few bacteria 
 draw their nourishment direct from the air, forming carbonate 
 of ammonia and carbonic dioxide. The particles of rock decom- 
 posed by atmospheric agencies are at once covered by this micro- 
 scopic vegetation which produces organic acids which help to 
 dissolve the particles of rock and cause them to crumble into dirt. 
 
80 Soils oi' California 
 
 Some bacterial secretions form organic compounds with minerals 
 as when lime is converted into calcium acetate, calcium formate, 
 malate, butyrate, etc., while othre bacteria in turn break these 
 compounds up into others. 
 
 MOISTURE. Bacteria demand moisture. A decrease in 
 moisture decreases their activity. They thrive or languish also 
 according to the concentration of the soil solution. Too high a 
 concentration checks their growth or kills them outright. They 
 thrive best at optimum moisture. 
 
 TEMPERATURE. The most favorable temperatures range 
 from 70 to 110 degrees F. Thus their action is largely limited 
 to summer temperatures. Dessication, as in desert regions, re- 
 tards their activities and thorough air drying of a soil paralyzes 
 the bacteria. 
 
 NITROGEN FROM THE AIR. Certain low forms separate 
 nitrogen from the air and from organic substances and combine 
 it with the potash, soda, etc., in the soil, but they cannot do this 
 unless the air penetrates the soil thoroughly. Their action is 
 confined largely therefore to the upper three feet of the soil, and 
 stores of insoluble nitrogenous material rest in the subsoils pre- 
 served from oxidation until they are brought to the surface. Nitri- 
 fication takes place deeper than six feet in many of the porous 
 well-ventilated soils of the arid and semi-arid regions of the west. 
 FAVORABLE AND UNFAVORABLE CONDITIONS. 
 Bacteria are much more numerous in some soils than in others. 
 The structure, tilth, and drainage of the soil determines largely 
 whether the aerobic or the anaerobic forms are to flourish. Each 
 soil possesses but one organism capable of oxidizing ammonia. 
 Soils from one locality have always the same kind of nitrifying 
 ferment. Soils from distant and different lands contain nitrify- 
 ing organisms which differ from one another in some respects. 
 The upper layers of the soil are exceedingly rich in bacteria but 
 they diminish rapidly with depth and at four or six feet largely 
 disappear except in the soils of the arid and semi-arid regions. 
 Bacteria grow most freely in arable soil containing considerable 
 humus, or rich in organic matter. In these the number becomes 
 very large — from 1,000,000 to 5,000,000 bacteria per gram of 
 surface soil. 
 
 The more vigorous the decomposition changes, the higher 
 the fertility of the soil. Black marsh soil shows the highest rate 
 
Obganic Matter in Son, 81 
 
 of decomposition, clay soils show less, and sandy soils the least 
 rate. If a soil is acid bacterial activity is checked, while the ac- 
 tivity of moulds and larger fungi are increased. The physical 
 conditions of the soil must favor decomposition. Hard packed 
 soils are inferior to looser soils in this respect. Where oxygen 
 (air) cannot penetrate the soils they become sour or acid, check- 
 ing bacterial activity. Lime may aid in neutralizing this acidity, 
 but aeration will do more. Sandy soils contain less micro-or- 
 ganisms than the loams and clays. Compact clays and loams 
 exclude air, checking nitrification by bacteria. Water logged 
 soils contain but few bacteria. 
 
 HIGHER FUNGI. Molds, mushrooms, fungi of all kinds, are 
 agents in the decomposition of vegetable matter so that it may be 
 incorporated in the soil, and be used again in the economy of 
 nature. Some of these may be beneficial to food plants, but 
 their products or excreta are often detrimental and toxic. The 
 thread-like roots (mycelium) are able to push between wood fibres 
 and between minute voids in the mineral particles of the soil. The 
 molds are not so rich in nitrogen as the saccharomycetes, or the 
 bacteria, and cannot assimilate nitrogen from the air. They de- 
 rive carbon from a great variety of organic substances. They 
 flourish only on the surface of the nourishing material and do 
 better in a sHghtly acid medium than in one that is slightly alka- 
 line. As already stated, if the soil is acid, bacterial activity is 
 checked. It is evident therefore that the activities of molds and 
 the larger fungi are then increased. They break down woody 
 matter, facilitating the work of decay bacteria. They produce 
 the dark colored matter which gives soils rich in vegetable ma« 
 terial their dark color. The necessary mineral materials for their 
 growth are phosphoric acid, potash and lime. 
 
 There are humble plants, such as lichens, mosses, ferns, etc., 
 which thrive upon what seems to be bare rock. The lichens 
 have no true roots but spread their thin substance over the rocks 
 and secrete acids which etch and dissolve the mineral matter, and 
 the mosses take up the work where the lichens leave off, while 
 the ferns take advantage of the thin soil left by these predecessors 
 in every tiny crevice and gain a foothold. These humble plants 
 shade the surface of the rocks and retain moisture which aids in 
 the further decomposition of the rock and its conversion into soil. 
 ENZYMES, or unorganized ferments, play a very important 
 
82 Soils of Calxfobnia 
 
 part in the fermentation of manure and the preparation of it for 
 its best efifects on certain soils. This fermentation does not pro- 
 ceed well with too much aeration, hence the need for compacting 
 a very loose soil. The subject of enzymes, however, belongs to 
 the study of agricultural chemistry rather than to soils. 
 
 HUMUS. The active principle of vegetable mould is called 
 Iu())iiis. a general term for products of the decomposition of vege- 
 table matter no matter what the special agent may be. It is the 
 chief depositor}' of nitrogen, which is the most costly as well as 
 most necessary of all plant foods. Vegetable matter decomposes 
 under the action of bacteria, molds, and enzymes. The composi- 
 tion of humus has not as yet been definitely determined, as it is 
 a mixture of many substances mostly acid. Sawdust humus con- 
 tains one to two per cent of nitrogen ; oatstraw humus contains 
 from two to four per cent ; clover humus from four to eight ; and 
 meat scrap humus from eight to nine per cent of nitrogen. The 
 humic acid in black soils is almost exclusively in combination 
 with lime. The decay of humus is most rapid in drained and 
 open soils. Clay promotes the accumulation of humus. Few 
 upland arid soils contain over 0.4 per cent of humus, but this 
 humus is richer in nitrogen than the humus of regions of consid- 
 erable rainfall. The chief functions of humus are to modify, 
 the physical conditions of the soil with reference to texture, mois- 
 ture, absorption of heat, and to hold in suitable form the nitro- 
 genous principles of vegetable matter ; but it is not assimilated 
 directly itself. It makes soils lighter and of better tilth, enables 
 them to absorb more moisture, and makes them warmer. 
 
 ANIMAL LIFE IN THE SOIL. Earthivonns not only obtain 
 nourishment from the organic matter of the soil, but take in the 
 inorganic. They pass the soil through their bodies leaving it in a 
 granulated condition in the "casts" which they deposit. It is esti- 
 mated that in a favorable soil in a humid climate as much as 
 eleven tons of dry earth per acre passes through their bodies 
 and that 0.18 per cent of their secretions consists of soluble ni- 
 trates in the form of ammonia. They modify the soil mechan- 
 ically by bringing to the surface particles of the subsoil ; the holes 
 left by them increase aeration and drainage, and the soil is made 
 more porous and easily pulverized. They aflfect the soil chem- 
 ically by acid and alkali reactions as the soil passes through their 
 bodies, leaves and other organic material being converted largely 
 
Organic Matter in Soil 83 
 
 into humus. Finally the bodies of the worms themselves become 
 fertilizing material and food for the bacteria and plant roots. 
 Worms naturally seek heavy, compact, and moist soils where 
 they are of the most benefit ; the sandy soils which do not need 
 them contain few. Ants with their busy colonies bring soil from 
 the depths and heap it on the surface, giving drainage, aeration, 
 and mixing the soil with subsoil. Beetles and a myriad of other 
 burrowing insects and animals cause movement of the soil par- 
 ticles and aeration and drainage and incorporate a considerable 
 amount of organic matter with the mineral matter present, and at 
 last contribute their own bodies to the sum total. 
 ACID SOILS. Soils rich in decaying vegetable matter may 
 show a distinct acid reaction. Even very acid soils contain but 
 little acid, or acid salts, soluble in water. The humic and ulmic 
 acids and their salts are chiefly responsible for the harmful acidity 
 of soils. Acidity exerts a marked influence upon the 
 crop-producing power of the soil, as it affects both its physical 
 and chemical condition, (1) through its action upon the micro- 
 organisms which in turn modify the physical condition, and (2) 
 by the direct action of the acids upon the tender rootlets. Crops 
 grow best when the soil is neutral, that is, neither acid nor alka- 
 line. Lime and limestone are the best correctives. Soils in the 
 arid regions are more apt to be alkaline than acid. 
 
CHAPTER XII 
 
 SUBSOIL. SOIL MOVEMENT. SOIL 
 PERMANENCY 
 
 SUBSOIL. This is the part next below the surface soil, and 
 the distinction between soil and subsoil lies almost wholly in the 
 color and texture, the composition being very much the same, 
 as a rule. Generally the subsoil is soil in the process of mak- 
 ing, or raw unfinished soil, as the surface soil is often only the 
 weathered or rotted subsoil ; and the subsoil in turn is only a 
 phase of the rotted bedrock below. The character of the sub- 
 soil afifects the water-holding capacity of the soil above. Thus 
 a gravel subsoil, or sand subsoil, gives perfect drainage, while 
 a clay subsoil interferes with drainage. The nature of the sub- 
 soil affects the productiveness of the soil. An impervious sub- 
 soil, or a very loose sandy one, confines the productive zone to 
 the top soil. An old English ballad says : 
 "Clay on sand is money in hand ; 
 Sand on clay is money thrown away." 
 While this may be true in the humid climate of the "right 
 little, tight little island" it is untrue in an arid climate. Climate 
 modifies the relation of the subsoil to the soil. In humid regions 
 of large rainfall and seepage, the subsoil is finer and more com- 
 pact than the soil from the washing downward of the finer par- 
 ticles. In the arid regions the subsoil is inclined to be coarser 
 than the soil above. In humid regions the subsoil is less produc- 
 tive than in the arid regions owing to the greater amount of 
 leaching. Occasional deep plowing brings some of the subsoil 
 to where it is exposed to the atmospheric weathering, and the 
 action of plant roots, and humus, so that it becomes in time 
 surface soil. Most soils formed under arid conditions are sandy, 
 and there is little or no clay to be washed down into and com- 
 pact the subsoil, the result being that air and water circulate to 
 greater depths than in the soils of the humid regions. The dis- 
 tinction between soil and subsoil is slight in the arid regions ; or 
 the soils are so deep that there is no subsoil within the depths 
 which tillage can be made to reach. There are exceptions to this 
 
Subsoil Soil Movement Soil Permanency 85 
 
 rule in the arid regions, as in the case of marsh, swamp, lacus- 
 trine soils, or where bedrock comes close to the surface. In the 
 arid regions the farmer may be said to own three or four farms, 
 one above another, as compared with the same acreage east, for 
 he finds hop roots going down as much as fourteen feet without 
 lateral expansion ; grape roots going down twenty feet ; alfalfa 
 twenty-five to thirty, etc. Another illustration is the fact that 
 the earth from cellars and house foundations is fearlessly put onto 
 gardens on which fruit, flowers, and vegetables grow in the first 
 year. The irrigator also levels slopes, hillsides, and terraces 
 with no idea of discrimination between soil and subsoil, and the 
 results justify his action. Calcareous or limey subsoils enable the 
 farmer to enrich the surface by deep subsoil plowing. In shallow 
 soils the nature of the subsoil should be closely observed. 
 
 SOIL MOVEMENT. The predominant factor in the pro- 
 duction of a crop is the amount of available mineral plant nutri- 
 ents in the soil, joined to the physical condition of the soil. For 
 years the idea has prevailed that a given field or soil mass stays 
 in place indefinitely and without changes, except such as are pro- 
 duced by cultural methods. This is not at all the case. It is 
 now known that the soil must be dealt with as a living thing in 
 the sense that it is ever in motion. The root of the plant is al- 
 ways in action, while the plant lives ; the soil solution (the blood 
 of the soil body) is always in motion, and if it stops and is stag- 
 nant the soil is dead ; the soil atmosphere is constantly in motion 
 and changing, for the soil must breathe ; the life of bacteria, etc., 
 in the soil affects its sanitary condition or health. Soil is not 
 a dead, inert mass, but in constant action. The particles are in 
 motion from freezing and thawing, and every change in the mois- 
 ture content is accompanied by motion. The activities of insects, 
 earthworms, burrowing animals like beetles, gophers and moles, 
 are constantly translocating soil material. Ants bring about 
 large transfers from lower to higher levels, and their borings 
 admit air and water to the deeper lying portions, promoting 
 further chemical and physical changes. The angleworm or earth- 
 worm is one of the most important of the soil builders, loosening, 
 aerating, fining and draining the soil and subsoil. A soil is not 
 dead, but teems with life and hums with activity. Countless 
 organisms visible only to the microscope are ever at work soil 
 building, soil destroying, and soil changing. Water action in 
 
86 Soils of California 
 
 translocation is restricted only by the fact that water can run 
 down hill only, but the wind is constantly in action and blows 
 uphill as well as down, and sidewise. It is a striking fact that 
 articles left lying on the ground gradually sink below the sur- 
 face. Even a layer of ashes or lime will sink as a layer and be 
 found a few years later as a distinct stratum below the sur- 
 face. The slow and unnoticed drift of materials backward and 
 forward by wind and water are ever afifecting the soil. The 
 accumulations of dust, so evident to every housewife, are un- 
 noticed in the field by the average farmer, yet they are very 
 important, for they amount to several tons per square mile, or 
 section of land each year. 
 
 It is a fact that must be taken into consideration that the 
 soil of a particular field, especially one under cultivation, is not 
 just the soil that was there a few years ago, or just the soil that 
 will be there a few years from now ; and that this movement at 
 normal is beneficial and an important factor in maintaining fer- 
 tility, but when abnormal, as under wind erosion, etc., it is bane- 
 ful. The control of the wind action is met by windbreaks, cover- 
 crops, etc., and that by water erosion by forestration, rotation 
 schemes, cultural and other methods. The persistence of a soil 
 is the persistence of the soil layer rather than of the individual 
 particles, just as the maintenance of our own bodies consists in 
 maintaining its health and form while the individual particles of 
 which it is composed are forever changing. Soils are always in 
 the process of change, and soil conditions are not static, therefore, 
 but dynamic. 
 
 SOIL DETERIORATION. Soils vary greatly in their 
 power of endurance. Most soils deteriorate through neglect and 
 insufficient and injudicious cultivation. They deteriorate even 
 with fairly good treatment under the one-crop system, whether 
 it be wheat, corn, cotton or tobacco. They frequently deterior- 
 ate through erosion where the top soil is removed, leaving the 
 unwcathered subsoil as the medium of growth. A complete dry- 
 ing out of the soil for a prolonged period usually brings beneficial 
 changes. Infertility is often due to the presence of toxin bodies, 
 and other causes already mentioned. 
 
 SOIL PERMANENCE. Many gloomy predictions have 
 been made regarding the probable failure of the soil to support 
 the increasing population of the earth. Such predictions seem 
 
Subsoil Soil Movement Soil Permanency 87 
 
 absurd to soil students. Proper drainage, cultivation, aeration, 
 rotation and fertilization maintain the sanitary conditions in the 
 soil, and renew the productive capacity of so-called dead and 
 zvornout soils. If the practice of agriculture has ruined land, 
 the science and art of agriculture must restore it. If the youth 
 of the civilized nations were required to take a three years' course 
 in agriculture instead of their militia training, the talk about 
 wornout soils would die out with the talk of the necessity of 
 colonization for the excess population. The work of the U. S. 
 Bureau of Soils alone in several states shows that there is no 
 actual exhaustion of the mineral plant foods in the soils that 
 were called exhausted, wornout, and impoverished, because agri- 
 culture had declined there. Soils are not impoverished of their 
 mineral plant food contents within the finite range and experi- 
 ence of human knowledge. The Bureau has proven that a mere 
 change in cultural methods has worked wonders, and in five 
 years many of the so-called exhausted soils yielded better than 
 formerly. 
 
 The older agricultural soils of Europe and Asia contain the 
 same common rock-forming minerals of the newer soils of the 
 United States, and there is no essential difference in their chem- 
 ical composition. The lands of Europe have been occupied for 
 a thousand years without a noticeable reduction of the plant 
 food element as compared with the newer soil of this country. 
 
 Many sections of China have undoubtedly supported an agri- 
 cultural population for centuries longer than the soil of Europe, 
 but there is no sign of deterioration of these soils. The soils 
 of Europe are not only not wearing out but are improving in 
 their yield. This increase is due to better methods of cultiva- 
 tion, care in the selection of seed, increase of livestock, use of 
 scientific fertilizers, proper drainage, aeration, systematic rotation 
 of crops, etc. It is aided by the fact that one family and its 
 descendants occupy the same farms one generation after another, 
 and become intimately acquainted with each soil and its peculiari- 
 ties. The fertility of the soil can be temporarily impaired, but 
 soils do not wear out in the sense that this term has been used 
 in the past, and there is no permanent wide-spread exhaustion 
 or deterioration of the soil. The soil will not be exhausted of 
 any one or all its mineral food contents, but is safe as a national 
 asset as a means of feeding and clothing mankind for the ages 
 yet to come. 
 
CHAPTER XIII. 
 CLASSIFICATION OF THE SOILS 
 
 In any one of the provinces of California will be found soils 
 derived from the same materials formed through the same agen- 
 cies, and having certain chemical and physical characters in com- 
 mon, but dififering in texture, and exhibiting all gradations from 
 clay to gravel. The soil minerals found in the soil provinces do 
 not differ materially in character, but the soil peculiarities of 
 each province are the result of different agencies, such as climate, 
 topography, etc. It makes a difference whether the soil is in a 
 humid, arid, or semi-arid province. The differences in the prop- 
 erties of the several grades of materials, or size of the mineral 
 particles, gives rise to various soil types, classes, or groups. 
 
 SOIL SERIES. A common name taken from some typical lo- 
 cality is given to each soil series, such as the Sacramento series, 
 Imperial series, or San Joaquin series, showing types formed in 
 the same general way. 
 
 SOIL CLASSES. All those soils having the same general tex- 
 ture, no matter how derived, constitute a soil class, as the sandy 
 loams, sands, loams, and clays. Every farmer knows that there 
 is a great difference between sand and clay, that they must be 
 handled different, and are suited to different crops ; but he does 
 not know always that the cause is due to the different size of the 
 soil units. 
 
 SOIL PARTICLES. The grade of material entering into a 
 soil is determined by the size of the particles, the measurements 
 being in millimeters. A millimeter is the thousandth part of a 
 meter or .001 m, and is equivalent to the 0.03937 part of an inch. 
 It is denoted by writing mm. after the figures as 1 mm. is a milli- 
 meter. The standards are as follows : 
 
 Gravel 2. to 1. mm. 
 
 Coarse sand 1. to 0.5 mm. 
 
 Medium sand 0.5 to 0.25 mm. 
 
 Fine sand 0.25 to 0.1 mm. 
 
 Very fine sand 0.1 to 0.05 mm. 
 
 Silt 0.05 to 0.005 mm. 
 
 Clay 0.005 to 0.0000mm. 
 
 Material larger than 2 mm, or 0.08 of an inch, is classified 
 
Classification of the Soils 89 
 
 as pebbles, cobbles, boulders, etc., and is not included in the soil 
 analysis, but described in connection with the land. 
 
 The combination of different percentages of the particles or 
 units, or the combination of these units in different proportions, 
 form the soils known as sand soil, fine sand soil, sandy loam soil, 
 fine sandy loam, loam, silt loam, clay loam, and clay soils. There 
 are also phases of these soils, as gravelly sands, loamy sands, 
 stony loams, or stony clays, which may in certain provinces be 
 included in a group, and in other provinces be set aside as subor- 
 dinate soils of little agricultural value. 
 
 SOIL NAMES. All those soils having the same general 
 texture, no matter what their derivation, have the same class name, 
 as sandy loam, silt, fine sandy loam, etc. They are named accord- 
 ing to the relative proportions of the different particles or units 
 entering into their composition. The rules for naming are as 
 follows : 
 
 Soils containing : 
 
 (1) Less than 20 per cent of silt and clay together, are 
 called : 
 
 COARSE SAND, if they contain more than 25 per cent 
 of fine gravel, and less than 50 per cent of any other grade. 
 
 SAND, if they contain more than 25 per cent of fine gravel 
 and medium sand, and less than 50 per cent of fine sand. 
 
 FINE SAND, if they contain more than 50 per cent of 
 fine sand, or less than 25 per cent of fine gravel, coarse and 
 medium sand. 
 
 VERY FINE SAND, if they contain over 50 per cent of 
 very fine sand. 
 
 (2) From 20 to 50 per cent of silt and clay, are called: 
 SANDY LOAM, if they contain over 25 per cent of fine 
 
 gravel, coarse and medium sand. 
 
 FINE SANDY LOAM, if they contain over 50 per cent 
 of fine sand, or less than 25 per cent of fine gravel, coarse and 
 medium sand. 
 
 SANDY CLAY, if they contain less than 20 per cent silt. 
 
 (3) Over 50 per cent of silt and clay are called: 
 LOAM, if they contain less than 20 per cent clay and less 
 
 than 50 per cent silt. 
 
 SILT LOAM, if they contain less than 20 per cent clay, 
 or over 50 per cent silt. 
 
90 Soils of California 
 
 CLAY LOAM, if they contain 20 to 30 per cent clay, or less 
 than 50 per cent silt. 
 
 SILTY CLAY LOAM, if they contain 20 to 30 per cent 
 clay, and over 50 per cent silt. 
 
 CLAY, if they contain over 30 per cent of clay, etc. 
 HEAVY AND LIGHT SOILS. The sands, sandy loams 
 and fine sandy loams are generally referred to as light soils. The 
 loams, silt loams, clay loams, and silty clay loams are referred 
 to as heavy soils. This refers not to the weight per cubic foot 
 of the soil, but to the draft required in plowing, cultivating, etc. 
 Fine material of this kind is held in a plastic or coherent condi- 
 tion and requires more power to plow and cultivate than it does 
 on loose or only slightly coherent soils of the sandy groups. The 
 yields are also generally larger and more bulky on the loam and 
 clay groups than on the sandy groups and this requires heavier 
 teams for harvesting the crops as well as to prepare them. 
 DEPTH CONSIDERED. In naming a soil the texture of 
 the surface soil and of the subsoil to a depth of three feet in the 
 humid states and six feet in the arid states is taken into consider- 
 ation. There are soils that have a sandy surface soil and a clay 
 subsoil, and occasionally there is a clay soil that has a sandy sub- 
 soil, affecting the adaptability to crops. When a soil is referred 
 to by name as the Imperial sandy loam, the term soil in this 
 sense includes both the top and the subsoil. In sampling soils, 
 the top soil and the subsoil are kept separate, and if the subsoil 
 shows two layers of different texture these are separated also. 
 SOIL SERIES. Where soils have a common origin, and 
 differ only in texture and are alike in color and physical prop- 
 erties other than those affected by texture, they are arranged in 
 what is called a scries, having the soil generic name with quali- 
 fying textural terms. We have for example the Placentia soil 
 series, named for the type locality around Placentia, in Orange 
 County, California. This series is divided into classes known 
 as the Placentia sandy adobe, Placentia sandy loam, Placentia 
 fine sandy loam, Placentia loam, Placentia loam adobe, Placentia 
 clay loam, and Placentia clay loam adobe. The same type of soil 
 receives the same name, and members of the Placentia series are 
 found around Riverside, Redlands, Perris. and other localities re- 
 mote from the type locality. Members of the Hanford series are 
 found also around Los Angeles and San Bernardino. 
 
Classification of the Soils 91 
 
 Other things being equal, the water holding capacity of the 
 soil will vary as the texture varies ; the light sandy types holding 
 on an average not over four per cent of water, while the clay 
 members may hold as high as twenty per cent of moisture. This 
 difference in moisture creates a corresponding difference in the 
 soil atmosphere and oxidation is usually more rapid in the sandy 
 than in the clay members of a series. The effect of these differ- 
 ences of soil texture upon the adaptation of soils to crops and 
 upon crop production is well known, and is stated under the 
 descriptions of the soils. The iuoisture of a soil is defined as fol- 
 lows : zi'ct, when water drips from a piece held in the hand without 
 pressing ; moist, when water drips from a piece pressed in the hand ; 
 fresh, when no water drips from a piece pressed in the hand, 
 although it is evidently present ; dry, when there is little or no 
 trace of water present ; and very dry, when the soil is parched. 
 The depth of soil is indicated in terms which have their equivalent 
 in inches, thus, I'ery shallozv means less than six inches ; shalloiv 
 means six to twelve inches ; moderate means twelve to twenty- 
 four inches ; deep means from twenty-four to thirty-six inches ; 
 and very deep anything over thirty-six inches. In doing the field 
 work of classifying soils, all features are taken into consideration 
 which in any way appear to influence the relation of the soil to 
 crops. The classification is based mainly but not wholly upon the 
 physical properties and conditions of the soil. Any chemical 
 features such as deposits of marl, of highly calcareous soils, or 
 of highly colored soils is considered. The character of the na- 
 tive vegetation, or its absence, and the condition of crops growing 
 is noted as a prominent factor. The topography of the country 
 is often a safe guide in outlining the boundaries of soil conditions. 
 
 Local variations in the character of the soil less than a quar- 
 ter of a mile in extent are generally ignored, unless this varia- 
 tion constitutes a very prominent feature, such as a strip of 
 meadow land along a stream, or unless there are a number of 
 small areas by which character is given to the district, such as 
 rocky areas, small each, but extending in the aggregate over 
 large areas. For example, Meadow Land is not only a distinc- 
 tive feature, but it is a very fine sediment of silt and very fine 
 sand, which is easily recognized as distinct from the other soils 
 of the valley. Loam is a grade coarser than the meadows, and 
 the character of the vegetation and the relation of crops in the 
 field is very marked. In some places the classification of the 
 
92 Soils of California 
 
 soils has to be made mainly from the distribution of the native 
 vegetation, where the different classes of soils vary but little in 
 their physical and chemical properties, but show a very great 
 difference in their native vegetation and in their adaptation to 
 crops. The survey of alkali lands involves special determina- 
 tions and observations in the field. There should be a soil map, 
 the alkali map, the underground water map, and where black 
 alkali, or sodium carbonate exists in appreciable quantities, a 
 separate map showing the distribution and percentage of this 
 pernicious substance. As a rule, the clay soils on the flats and 
 draws contain the greater amount of alkali, the loam soils next, 
 then the sandy loams, and finally the sandy soils. This is due 
 partially to texture and its influence on the drainage, and par- 
 tially to the physiography of the country as to drainage. 
 ADAPTATION OF SOIL TO CROPS. The influence of 
 abrupt topographical changes, as our mountain ranges and ele- 
 vated plateaus, tend not so much to modify the character of the 
 soil, as they do the character of the crops that may be raised to 
 advantage. The slope and the elevation has the effect of adapt- 
 ing the land to special crops, and call for different methods of 
 soil management. The climates of each province are widely 
 different and affect the class of crops that may be raised, 
 as the desert sand may be well adapted to date culture, 
 while sands in a colder climate would not be. There is remark- 
 ably little true clay in California such as is found in the east, 
 but sands, loams and silts predominate. Some soils have adobe 
 properties which are unusual in the east. The soils of the west 
 are generally freer from toxic organic bodies than eastern soils, 
 and are capable of producing maximum crops under irrigation 
 and intensive culture. Plants develop a much deeper root sys- 
 tem than on the soils of the east. The fact that there is little 
 difference in texture between the soil and subsoil, that rains are 
 infrequent, the atmosphere dry, and the surface evaporation rapid, 
 enables the farmer to maintain a more efficient surface dry mulch, 
 making it possible to produce good yields of crops with remark- 
 ably light rainfall, and frequently without any rainfall at all, dur- 
 ing the growth of the crop. The climate limits broadly the zone 
 or area in which certain field crops may be grown, and affect 
 the yield and quality of the crop. In California, the arable lands 
 vary from below sea level to elevations 6,000 feet above. The 
 greatest precipitation comes in the winter season. There is a 
 
Classification of the Soils 93 
 
 wide difference in the provinces in the relative humidity and sun- 
 shine, as there are differences in the range of temperatures daily 
 and seasonal ; and there are differences in the length of the grow- 
 ing season. There are also differences due to exposure, slope, 
 etc. All of these points have to be taken into consideration in 
 determining the special fitness of a soil for any particular grade, 
 quality or kind of product. 
 
PART V 
 
 CHAPTER XIV. 
 KEY TO CALIFORNIA SOILS 
 
 The following artificial key to the soils of the state gives a 
 method for identifying or classifying a soil tentatively from its 
 origin, appearance, or position, and finding out what series it be- 
 longs to or most closely resembles. While it covers the principal 
 series it is impossible to include all the purely local soils and their 
 variations. These may be identified locally by comparing them 
 with other members of the same class. 
 
 Thus if a soil is recognized as a silty clay loam, a comparison 
 of the soils described under that head will show wherein it 
 resembles or differs from those already identified and classified, 
 and whether it belongs to an established series or not. 
 
 The broad natural divisions are based on the origin of the 
 soils, viz : 
 
 A— RESIDUAL SOILS. 
 B— COLLUVIAL SOILS. 
 C— ALLUVIAL SOILS. 
 
 RESIDUAL SOILS. The residual soils may be subdivided 
 as follows : 
 
 Derived from granitic rocks : Black color, Portersville series. 
 Brown, Daulton. Chocolates, Arnold, red. Media. 
 
 Derived from granites, slates and volcanic rocks : red, Sierra. 
 
 Derived from granitic and metamorphic rocks : Pleasanton. 
 
 Derived from granite and shale : brown, Encinal. 
 
 Derived from sandstone : Contra Costa. 
 
 Derived from sandstone and shale : Altamont, Santa Cruz. 
 
 Derived from shales and conglomerate : Watsonville. 
 
 Derived from limestone : Diablo. 
 
 Derived from lava : Tuscan. 
 
 Derived from metamorphic rocks : Vallecitos, 
 
 Derived from the Red Bluflf formation : Tehama. 
 
Key to Caxifobnia Soils 95 
 
 COLLUVIAL SOILS. The colluvial soils may be divided 
 as follows : 
 
 Derived from granitic or volcanic material : Dark colored, 
 Maricopa. Reddish brown with clay or sand subsoil : 
 Placentia. 
 Derived from granodiorite or gabbrodiorite : Black from 
 
 hornblende or mica, Sheridan. 
 Derived from andesitic rocks, tuffs and breccias : Sutter. 
 Derived from shale : Salsipuedes, Danville. 
 Derived from sandstones, shales and shaly sandstone : 
 
 Oxnard. 
 Derived from sandstones, shales, conglomerate, and volcanic 
 
 rocks : Sites. 
 Derived from recent marine deposits : Indio. 
 COLLUVIAL, modified by mixture of alluvial, valley soils: 
 
 Dublin, Livermore, Sunol, Ulmar. 
 ALLUVIAL SOILS— WELL DRAINED: 
 River and stream deposits : 
 
 Along the Colorado River bottom : Gila. 
 
 On the Colorado delta : Imperial. 
 
 From shales and sandstones : Yellow brown. Esparto. 
 
 Black, Pajaro. 
 On bottom lands : Orland. 
 On lower benches and plains : Yolo. 
 At base of foothills : Oakdale. 
 On minor creek bottoms : Elder, Mocho. 
 On Upper Valley Plains: 
 
 Gravelly bottoms of intermittent creeks : Anderson. 
 Upper valley floors : Arbuckle, Maywood. 
 On broad deltas, cones, sloping plains : Fresno. 
 River and delta plains : Hanford. 
 On upland mesas : Santiago. 
 On plains : Gridley. 
 
 From Red Bluff formation : Corning, Kirkwood, 
 Redding. 
 ALLUVIAL SOILS— POORLY DRAINED. 
 
 Lacustrine origin, temporary lakes : Capay. 
 
 Coastal, drab, rushes, tules, Alviso clay. Black: sloughs 
 
 and marine salts : Galveston clay. 
 Recent stream deposits, overflowed : Sacramento, Alamo, 
 Feather. 
 
96 Soils of California 
 
 Swamps : Santa Rita. 
 
 Wash from more elevated soils : Lime hardpan, Stock- 
 ton. Many local soils. 
 
 Valley plains : Red, hardpan : Madera, San Joaquin. 
 (A) RESIDUAL SOILS. These are derived from the direct 
 weathering of rock in place. They are gravels, sands, or clays, 
 or other soils that are the actual residues or products of rock 
 decay, occupying the sites of the rock masses from which they 
 are derived. There may be as many kinds of residual soil as 
 there are kinds of rock. They are sometimes called sedentary 
 soils in place. They may be shallow and marked by abundant 
 outcrops of rock, boulders and rough rock areas, or they may 
 accumulate to great depth and the underlying rocks not exposed 
 except where the erosion has been excessive. They generally 
 contain sharp fragments of the undecomposed bedrock which 
 increase in size and number downward in the soil. They are 
 highly colored as a rule, usually red or yellow from the accu- 
 mulation and alteration of iron salts. Thus a gray limestone may 
 produce a red clay soil. They are seldom uniform in texture 
 and the clays are usually gritty. They are commonly found or 
 occur on rock plateaus, on plains where bedrock is near the 
 surface, and in granitic, volcanic and basaltic areas. They occur 
 also along the bases of mountains, foothills and covering low hills 
 and rolling ridges. The texture of these soils and the surface 
 slope is such that there is usually good drainage. 
 PORTERSVILLE SERIES. The type locality is in the 
 Frazier Valley, near Portersville, where these soils occur along 
 the lower slopes of the foothills. They are derived from the 
 underlying granite, but are more or less modified by alluvial 
 agencies and wash. The color is generally black from organic 
 matter, but may vary from dark red to brown locally. 
 
 DAULTON SERIES. The type soil is found in the Madera 
 district. They are formed by the decomposition of the granite 
 and quartz rocks of the foothills. The color is brown to red 
 brown. Not extensive, and generally used only for dry farming 
 to grain. 
 
 The Arnold soils of the Modesto-Turlock area occupy the 
 foothills of the Sierras. These hills are of sedimentary origin 
 and were once part of a gently sloping smooth ocean or lake 
 bed that occupied the Great Valley. When this portion was 
 
Key to California Soils 97 
 
 raised above water it was carved by erosion into its present form. 
 The predominating outcropping beds of the southern hills of this 
 area were very largely granitic in origin, weathering into the 
 chocolate-colored soils which have no true hardpan and are un- 
 derlain at various depths by the sedimentary formations from 
 which they were derived. They have been greatly modified by 
 rain, wind, plant life, and other agencies since first formed. 
 MEDIA SERIES. The types soils are found in the Madera 
 area on the high rolling foothills of the Sierra Nevada. They 
 have a typical red color. 
 
 SIERRA SERIES. The type soils of this series cover large 
 areas of valuable fruit and grazing lands along the western slope 
 and base of the Sierra Nevada mountains. They comprise soils 
 derived from the weathering of granitic rocks, diabase, altered 
 rocks, (such as amphibolites, slates, serpentine, and volcanic ma- 
 terials) with a slight admixture of colluvial and alluvial material 
 from the same sources. They are generally of light red to deep 
 red color, and of somewhat compact structure. They occupy 
 rolling and frequently mountainous districts and foothills, and 
 usually support a more or less heavy growth of brush and forest 
 trees. 
 
 PLEASANTON SERIES. The Contra Costa Hills on the 
 west and the Mt. Diablo Range on the north and east, in the 
 Livermore area, are composed of Tertiary and Cretaceous sand- 
 stones, limestones, conglomerates, and argillaceous shales, with 
 granitic and metamorphic rocks. The Pleasanton series are the 
 residues of granitic and metamorphic rocks and occur on the 
 uplands. 
 
 ENCINAL SERIES, The Encinal sandy loam occurs in the 
 resfion of Elkhorn Slough on the southern slope of the Monterey 
 Hills. It is dark brown to drab gray in color, with a whitish sub- 
 soil. The soil contains sharp fragments of granitic gravel and 
 shale. 
 
 CONTRA COSTA SERIES. The type soils are found in 
 the Livermore area and are derived from the weathering of the 
 Tertiary and Cretaceous sandstones of the Contra Costa and Mt. 
 Diablo Ranges. See Pleasanton. 
 
 ALTAMONT SERIES. The type soils are found in the 
 Livermore area, and are formed by the decomposition in place 
 
98 Soils of C.vlifoenia 
 
 of the shales and conglomerates of the Contra Costa Hills and 
 the Mt. Diablo Range. Sec Pleasanton. 
 
 SANTA CRUZ SERIES. The type soils of this series are 
 found in the Santa Cruz mountains and are derived from the 
 weathering of shales and sandstones in place. They are red 
 to dark brown in color. 
 
 WATSONVILLE SERIES. This series is derived from 
 shale, or from shale and conglomerate. They occupy low roll- 
 ing ridges and hills that form the plain north of the Pajaro River. 
 They are dark brown to red in color. 
 
 DIABLO SERIES. The type is found in the Livermore area 
 on the uplands, and are formed by the weathering of Cretaceous 
 limestones of the Mt. Diablo range. They are brown in color. 
 Fossil oysters are common in the soil in the type locality. 
 
 TUSCAN SERIES. The type soils are found in the Red 
 Bluff area, on the east side of the Sacramento Valley. They are 
 shallow soils, reddish brown in color, and are formed by the 
 weathering of the lava flows from Lassen Peak region. 
 
 VALLECITOS SERIES. The type soils are found in the Liv- 
 ermore area on the uplands, and are the result of the weathering 
 of the metamorphic rocks of the Mt. Diablo Range. See Pleas- 
 anton. 
 
 TEHAMA SERIES. The type soils are found in the Red 
 Bluff region lying above the alluvial plains along small streams, 
 on the west side of the Sacramento Valley. They are derived 
 from the weathering of the Red Bluff formation. 
 
 (B) COLLUVIAL SOILS. These take their name from 
 collis (a hill), as they are soils that move or creep slowly down 
 moderate slopes through the action of expansion and contraction 
 from heat and cold, and through the action of gravity, frost, and 
 rain wash. They consist of alluvium in part from wind sweep 
 and water wash, and also contain angular fragments of the 
 original rocks. They consist of unassorted colluvial, or only par- 
 tially sorted alluvial material formed by the soil creep, by direct 
 wash from the mountain side, and by the deposit of intermittent, 
 shifting, torrential streams. They occur as talus and cliff debris, 
 and as avalanche and slide material. They are found on hill- 
 sides, rolling and hilly uplands, on mountain slopes, on delta 
 cones or fans, debris aprons, and the sloping plains of filled val- 
 
Key to Calitobnia Soils 99 
 
 leys. They also occur in stream valleys as the product of a series 
 of secondary fans or cones emerging from adjacent more elevated 
 slopes or mesa lands. 
 
 MARICOPA SERIES. These soils are found in many local- 
 ities and are derived from a variety of rocks, but generally from 
 those of granitic and volcanic character. They are generally of 
 dark color and loose porous structure, well drained and free 
 from alkali. 
 
 PLACENTIA SERIES. The type locality is around the 
 town of Placentia in Orange county. They are distinguished 
 from the Maricopa by the prevailing reddish brown to reddish 
 gray color, and in being underlain by indurated sands, shaley sand- 
 stones, distintegrated granite, or by heavy compact red loams or 
 clays of tough impervious adobe structure. Generally well 
 drained and free from alkali, but somewhat refractory to culti- 
 vation. They are widely distributed, especially in the southern 
 part of the state. 
 
 SHERIDAN SERIES. The Sheridan sandy loam is a black 
 friable soil found in the Sacramento area. The characteristic 
 black color is due to the large proportion of black hornblende and 
 biotite mica crystals which it contains. 
 
 SUTTER SERIES. The type locality of this series is in the 
 vicinity of the Marysville Buttes. They are dark brown to black 
 in color and underlain by brown or yellow loams. They are 
 made up of material from the Marysville Buttes, which are com- 
 posed of andesitic rocks, tuffs and breccias. 
 
 SALSIPUEDES SERIES. The Salsipuedes loam of the 
 Pajaro Valley has been washed down from the shale mountains 
 and adjacent hills. It is brown in color and is underlain by loam 
 or sandy loam. 
 
 DANVILLE SERIES. The type is found in the Livermore 
 area on the valley floor and is formed from the shales of the 
 Contra Costa Hills and Mt. Diablo Range, as shown by the sharp 
 shale fragments in the soil. It is somewhat modified locally by 
 alluvial wash. 
 
 OXNARD SERIES. This series consists of delta plains de- 
 posits, colluvial and alluvial wash from the foothills. They are 
 derived mainly from sandstones and shales and occur on rolling 
 hills ; elevated and dissected mesa lands and plains, and delta 
 
100 Soils of California 
 
 plains. They are less elevated than the Maricopa, and are lacking 
 in the granitic material of that series. They are generally dark 
 colored, and underlain by heavier subsoils which do not have 
 the red color and adobe structure of the Placentia series, which 
 occupy similar topographic positions. 
 
 SITE SERIES. These are found on the slopes and across 
 the narrow valleys of the outer range of hills forming the western 
 edge of the Sacramento Valley in the Woodland area. They are 
 generally brown in color, with variable subsoils and are derived 
 from the sandstones, conglomerates, shales, and volcanic rocks 
 of the Coast Range. 
 
 INDIO SERIES. These soils are wholly wash from the 
 surrounding mountains of the Riverside and San Jacinto ranges. 
 They range from sea level to about 250 feet below sea level. 
 The surface of the Coahuilla Valley is covered with small shells, 
 showing that the soils were deposited under water and are the 
 weathering of recent marine deposits. They are all very sandy, 
 loose, friable, light colored, and show particles of quartz, mica, 
 granite, and volcanic ash, and are more or less wind blown. 
 COLLUVIAL, MODIFIED BY MIXTURE OF ALLU- 
 VIAL. Some soils are distinctly colluvial in origin and yet 
 are modified by considerable quantities of alluvial material 
 washed into them. The DUBLIN, LIVERMORE and SUNOL 
 soils of the Livermore area are valley soils, having largely a com- 
 mon origin and position but dififering in character and crop value. 
 The Dublin is black in color, and derived from shale ; the Liver- 
 more is brown in color and poorly drained ; the Ulmar is brown 
 in color and marked by hogwallows. Other characteristics are 
 given in the local description. The Sunol is a brown loam carry- 
 ing slate fragments, and has a clay loam subsoil. 
 (C) ALLUVIAL SOILS. These are recent deposits in val- 
 leys, on flood plains, bottom lands, and deltas of the detritus, 
 1)rought down chiefly by water. This includes recent alluvium, 
 marsh and swamp deposits, clays, and loess and adobe in part. 
 Such deposits are more or less distinctly stratified or bedded. 
 Their productiveness is due to their fine texture, their frequent 
 renewals by deposits from flood waters, and the variety of ele- 
 ments of which they are composed. They are the soils of the 
 valleys, flood plains and lake borders, past and present. They 
 occur all along the main stream courses, especially in the lower 
 
Key to California Soils 101 
 
 lands, where during flood season the water usually leaves the banks 
 and spreads over the flat lands adjoining. The sediments carried 
 down from the mountains and higher ground are spread out over 
 the bottoms in thin layers during flood time. Nearest the stream, 
 or wherever the current is swiftest, the coarser grades of sand 
 and gravel are deposited and build up the coarser textured soils. 
 Further away from the stream, or wherever the current is slug- 
 gish, the finer sediments like fine sand, silt and clay are deposited, 
 building up the finer textured soils. Along the larger rivers the 
 material may show distinctly that it comes from the mountains 
 of the interior. Along the smaller streams the soil consists of 
 the wash from the adjacent foothills and plains soils. They often 
 occur in long continuous bodies, paralleling the courses of present 
 or former streams, along the smaller intermittent foothill and 
 plains water courses, and as distinct alluvial fans where the 
 smaller streams flow into basins. Some are deposited in inter- 
 mittent lakes, some in the swamps at the margins of lakes and 
 some in the swamps and bayous covered by ocean tides. Many 
 of the low-lying members are subject to overflow, or the drain- 
 age may be deficient owing to the flatness of the surface, char- 
 acter of the subsoil, or to other local causes. Being of mixed 
 origin, their general character may vary from one extreme to the 
 other, both as regards physical and chemical composition. In the 
 upper portions of the valleys, where the slope is steep and the 
 velocity of the waters is high, cobbles and gravels are dominant. 
 As the slope decreases, first coarse and then fine sand will be 
 prominent, while still lower down the finest sand, then silt, and 
 finally clay will dominate. As streams in flood vary in velocity 
 from time to time, deposits of dififerent texture will often alter- 
 nate with one another on the flood plains. This is a distinguish- 
 ing mark of alluvial soils and is noticeable on terraces, benches, 
 and mesas, due to the elevation of the land or to the depression 
 of the river channel. On the lower slopes of hills bordering allu- 
 vial valleys the colluvial slope soils often alternate with the allu- 
 vial deposits. The alluvial soils may be divided in the two nat- 
 ural divisions of well drained and poorly drained, and these in 
 turn subdivided according to their principal characteristics. 
 
 GILA SERIES. These soils are formed from the deposits of 
 the Colorado River in its annual overflow. They are red brown 
 in color, loose and incoherent. 
 
102 Soils of Cajlifobnia 
 
 IMPERIAL SERIES. They occur in the Imperial Valley, 
 which is a portion of the Colorado River delta. This region was 
 once occupied by a northern extension of the Gulf of California 
 into which the Colorado River poured its sediment-laden stream, 
 building up an extensive submarine delta. Later the region be- 
 came a lagoon shut off from the sea. The marine and lagoon 
 phases are marked by extensive beach line deposits. The lagoon 
 phase fluctuated between salt and brackish water stages and was 
 later replaced by an arid basin that at its lowest point was 260 
 feet bclozi' sea level. Since that time repeated overflows of the 
 river have carried suspended sediments into the basin, burying the 
 older deposits at various depths. The surface materials from 
 which the soils are derived are not continuous, but form thin 
 irregular lenses of sediment. The chief agent now at work is 
 the wind, which excavates, transports and deposits a large quan- 
 tity of material annually. The greater proportion of the soils 
 consist of clay and silt, the heavier soils predominating. They 
 differ from the Gila series in being underlain by heavy sediments 
 of close nature. 
 
 ESPARTO SERIES. These soils are derived from material 
 transported by the minor streams of the foothills of the Coast 
 Range, and are of recent origin. They originate from shales, 
 sandstones and clays of the lower range of hills, and overlie the 
 older formations of the valley plain. They are generally yellow- 
 ish brown in color. 
 
 PAJARO SERIES. These are derived from shales and 
 sandstones, with an admixture of igneous and crystalline rocks. 
 They extend from the river to the hills of the Pajaro Valley. 
 The color is dark brown to black, due to the high per cent of 
 humus. 
 
 ORLAND SERIES. These consist of material from the 
 former and recent deposits of Stony Creek, in the Colusa area, 
 with an admixture of wash from adjacent soils, and occupy the 
 lower benches and plains. 
 
 YOLO SERIES. These soils are derived from material 
 transported by Cache and Putah creeks in the Woodland area. 
 They are deep, silty, and sandy, and generally brown in color. 
 
 OAKDALE SERIES. These are recent soils of old overflow 
 channels in the Modesto-Turlock area, with wash from adjacent 
 
Key to Califobnia Soils 103 
 
 soils. They are brownish in color, micaceous, and underlain by 
 lighter subsoil. They occupy a lower position than the Arnold 
 along the base of the foothills and on stream bottoms. 
 
 ELDER SERIES. The type soils are found in the Red Bluff 
 area, which covers the extreme northern part of the Sacramento 
 Valley and its adjacent elevated plains. The soils are derived 
 in part from the original deposits of the valley and from modern 
 alluvium brought in by the streams that traverse the area. The 
 Elder series are dark in color, deep and friable, and occupy the 
 alluvial bottoms of the major streams coming from the Coast 
 range on the west side of the valley. 
 
 MOCHO SERIES. The type soils are found in the Liver- 
 more area lying between the Contra Costa Hills and the Mt. 
 Diablo Range. They occupy the bottoms of the valley and are 
 still in the process of formation, being purely alluvial. 
 ANDERSON SERIES. These consist of reddish, gray, or 
 light red soils, occupying upper valley plains and the bottoms of 
 intermittent streams. They are usually gravelly, and underlain 
 by gravels or compact clay. 
 
 ARBUCKLE SERIES. These are derived mainly from 
 coarse conglomerates and slates deposited by streams on upper 
 valley floors, and are of comparatively recent origin. They are 
 generally of gray color and overlie clay formations. 
 MAYWOOD SERIES. The type soils are found in the Red 
 Bluff area. They occupy the terraces and alluvial fans of the 
 streams on the upper valley floor and are marked by terraces. 
 They occur on the west side of the Sacramento Valley, are grayish 
 in color, and more friable than the Tehama. 
 
 FRESNO SERIES. These are characterized by prevailing 
 light gray color, but are sometimes light red to reddish brown. 
 They are generally underlain by subsoils of fine ashy texture, 
 light color, and compact close structure, usually separated from 
 the overlying soil by an alkali carbonate hardpan of white or 
 light gray color. The series is composed of old delta deposits 
 formed by shifting streams and mountain torrents, and occuring 
 as broad, low, alluvial delta cones. They occupy gently sloping 
 plains or slightly rolling valley slopes. The origin is mainly 
 granitic, but from volcanic and sedimentary rocks also in part. 
 
 HANFORD SERIES. These are derived from a great vari- 
 
104 Soils of Califobnia 
 
 ety of rock material deposited as river and delta plains. Some 
 even consist of mining debris. They are generally light gray to 
 buff in color, but become dark drab, brown, or black in low areas. 
 The surface is generally level or slightly sloping, and is frequent- 
 ly marked by sloughs or interlacing channels of streams. They 
 occupy a lower topographical position than the Fresno series and 
 are of more recent origin, and some of the members are subject 
 to overflow. They do not have the ashy subsoil or white hard- 
 pan of the Fresno series. 
 
 SANTIAGO SERIES. This series is typical in the Santa 
 Ana area, where they occur on a delta plain of very recent origin. 
 This delta plain was built up by material brought by the Santa Ana 
 River and Santiago creek in times of flood, and by an elevation 
 of this part of the coast. The river has wandered over this 
 delta, covering it with alternating sandy soils, running in lines 
 parallel to the ocean. The soils are sandy and occupy some of 
 the higher elevations of the delta, and have a subsoil that varies 
 from sandy adobe to sandy loam. 
 
 GRIDLEY SERIES. This series in the type region at Marys- 
 ville is usually a little higher than the surrounding soils, on land 
 that varies from level to slightly rolling. The body of the soils 
 are sediments largely reworked by later alluvial agencies. They 
 are reddish brown in color, with loam subsoil, and with few ex- 
 ceptions are free from hardpan. It is an extensive type in Sut- 
 ter County, from the Red Bluff Formation (Pleistocene). 
 CORNING, KIRKWOOD, and REDDING series are named 
 for type localities in the Red Bluff area. They are 
 all derived from the geologic formation known as the Red Bluti 
 formation, and have a red color. The Redding series carries 
 water-worn gravel, and has a thin heavy subsoil resting on 
 hardpan. They are locally known as "Red Lands" and "Hardpan 
 Lands." They occupy the higher elevations of the Sacramento 
 valley and are gently rolling in character. The Corning series are 
 found on the west side of the Valley and are similar to the Red- 
 ding series except that the hardpan is absent. The Kirkwood 
 series are formed from the washing or erosion of the above 
 soils and are deposited on the lower valley plains, on local flats 
 and depressions. 
 
 THE CAPAY SERIES of the western part of the Sacramento 
 Valley consist of the finer grades of sediment resulting from the 
 
Key to Califoenia Soils 105 
 
 weathering of complex rocks of the Coast Range mountains and 
 deposited over the valley plain, where temporary lakes or pools 
 have been formed during periods of heavy rainfall and flood. 
 They are characterized by a dark gray color, fineness of texture, 
 and are of a heavy plastic character. Owing to the flatness of 
 the surface, the drainage is often deficient. 
 
 THE ALVISO CLAY is found near the seacoast, where the 
 tides at times cover the land, as at Elkhorn Slough in the Pajaro 
 Valley. It is a drab plastic clay, growing pickleweeds, tules, 
 saltgrass, etc. 
 
 THE GALVESTON CLAY is found around the waters of 
 San Francisco Bay. The surface is flat and only a little above 
 mean sea level. It is traversed by open tidal sloughs and rem- 
 nants of former drainage channels. It is generally black in 
 color at the surface and brown or yellow below. It originates 
 from the deposition of clay and the finer silt particles in the slack 
 water of the bay and its system of tidal sloughs and marshes. 
 
 SACRAMENTO SERIES. These soils consist of recent 
 stream deposits, generally light gray in color, although the siltier 
 soils may be darker. They were deposited from shifting river 
 currents or from relatively stagnant flood waters covering flood 
 plains, and are subject to overflow when not protected by levees. 
 
 FEATHER RIVER SERIES. These occur along the bot- 
 toms of the Feather, Bear and Yuba rivers, and are of a deep 
 brown color and silty texture. They are subject to overflow and 
 the drainage conditions are not very good. 
 
 ALAMO SERIES. These are plains soils of heavy clay loam 
 adobe, and clay adobe, dark red to black in color and underlain 
 by red hardpan. The surface is low and nearly level and when 
 wet is practically a bog. 
 
 SANTA RITA SERIES. The type is found in the Liver- 
 more area where the alluvium of the valley has a decided swampy 
 character. 
 
 STOCKTON SERIES. These consist in part of alluvium 
 and in part of wash from the more elevated soils. The heavier 
 members have been greatly modified by weathering and by the 
 decomposition of organic matter resulting from swamp or marsh 
 conditions. The}^ occupy extensive areas of the lower nearly 
 level plains of the Great Valley traversed by minor foothill 
 
106 Soils of Califobnia 
 
 streams. They are generally older than the Hanford series. The 
 lighter members are chocolate color, the heavier members are 
 black or dark brown. They are underlain by heavy loams or clay 
 loams of lighter color, separated from the soil by a thin white 
 calcareous hardpan free from alkali. 
 
 SAN JOAQUIN SERIES. The soils of this series are of a 
 prevailing red color, frequently gravelly, both gravel and soil 
 particles consisting of well-worn quartzose material. They are 
 commonly underlain by red or reddish brown indurated clay or 
 sandy layers cemented by iron salts into a fine hardpan. They 
 consist of old sediments deposited in the waters or about the 
 shores of lakes or bays of early Pleistocene age, modified by 
 recent reworking or by alluvial wash. They occupy valley plains 
 extending from the lower foothills down to level valley floors 
 and margins of present stream channels and are generally exten- 
 sive in area. The natural drainage is restricted by deficient 
 slope and the underlying hardpan. 
 
 SPECIAL SOILS. Not classified under residual, colluvial 
 or alluvial. 
 
 RIVER WASH. The miscellaneous deposits of sand and 
 gravel found along rivers and creek beds or spreading over inex- 
 tensive flood plains. 
 
 ROUGH STONY LAND. Stony hills or knolls covered by 
 rock outcrop and boulders with varying quantities of sand, loam, 
 and adobe composing the finer portion. 
 
 MEADOW SOILS. These comprise the low-lying, flat, 
 poorly drained land of variable texture and origin. Often ol 
 some value for grass or pasture. 
 
 PEAT or MUCK SOILS. These are composed largely of 
 organic matter in various conditions of decay. The muck is an 
 advanced state of change of the peat. 
 
 SANDHILL, DUNESAND, and COASTAL BEACH SOILS 
 
 are deep sands, often of little agricultural value. 
 
 LAKE and MARSH SOILS, such as those of Butte Valley 
 in the north end of the state, are formed by the drying up of 
 former lakes in an enclosed basin. The soils are loamy and too 
 wet for tillage, and often mucky or peaty. They are valuable 
 where drainage is possible. 
 
Key to Califobnia Soils 107 
 
 TABLE OF CALIFORNIA SOIL CLASSES. The follow- 
 ing table of the physical analyses of the various classes of Cali- 
 fornia soils is only tentative and subject to modification as new 
 classes are formed. It gives the average composition of the soils 
 so far as the work has been carried to date. As the work of 
 mapping the soils is extended, these averages will be changed to 
 some extent, and are therefore not fixed and final. They illus- 
 trate the differences in composition in a general way. 
 
 AVERAGE COMPOSITION OF CALIFORNIA SOILS 
 
 Very 
 Fine Coarse Medium Fine fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Clay 0.4 1.1 1.2 4.5 8.2 4a.l 44.1 
 
 Clay adobe 0.6 2.2 2.1 6.8 9.4 39.3 39.4 
 
 Silty clay adobe 1.1 1.7 1.6 4.0 6.0 52.1 33.4 
 
 Silty clay 0.2 0.4 0.5 3.4 3.4 59.6 32.1 
 
 Clay loam 0.5 1.5 1.5 9.5 19.7 41.9 26.7 
 
 Gravelly clay 
 
 loam 6.6 10.7 6.9 14.4 9.4 26.1 25.6 
 
 Silty clay loam.. 0.1 0.5 0.6 4.4 10.6 60.3 23.0 
 
 Loam adobes ... 2.4 6.1 4.1 14.7 19.5 28.9 22.8 
 
 Stony loam 4.6 7.6 4.9 13.1 15.4 31.2 22.7 
 
 Stony clay loam 1.6 5.6 4.5 8.5 17.6 39.4 22.5 
 
 Clay loam adobe 1.0 3.2 2.8 9.4 13.2 38.5 21.8 
 
 Silt loam 0.3 1.4 1.3 6.8 11.2 60.4 19.3 
 
 Loam 0.2 3.9 4.4 17.3 16.7 39.7 17.9 
 
 Sandy adobe 1.3 3.9 6.4 16.9 18.9 34.4 17.0 
 
 Gravelly loam .. 5.7 9.9 6.8 17.4 11.3 32.8 14.8 
 Gravelly fine sandy 
 
 loam 2.5 6.1 6.8 27.0 21.7 22.7 12.9 
 
 Stony sandy loam 7.4 14.7 7.9 11.7 16.9 28.9 12.3 
 Gravelly sandy 
 
 loam 8.9 13.2 8.1 16.3 13.3 29.3 10.5 
 
 Fine sandy loam 1.0 3.2 4.6 23.4 26.6 28.7 10.4 
 
 Sandy loam 3.7 16.1 12.9 24.7 12.5 23.7 10.2 
 
 Silty fine sandy 
 
 loam 0.0 0.2 0.5 14.6 32.8 41.9 9.9 
 
 Gravelly sand ..25.6 17.8 8.8 14.3 8.8 13.2 8.6 
 Coarse sandy 
 
 loam 9.8 29.4 10.7 17.7 6.0 18.3 7.5 
 
 Coarse sand 10.9 28.0 16.7 21.4 6.6 7.8 5.1 
 
 Loamy coarse 
 
 sand 8.1 22.3 12.7 21.7 25.8 5.6 3.8 
 
 Fine sand 0.4 2.8 4.7 39.3 31.5 16.4 3.8 
 
 Sand 1.5 12.7 23.6 37.8 12.6 7.6 3.7 
 
 Dune sand 0.0 24.7 46.3 25.2 0.8 1.7 1.6 
 
CHAPTER XV 
 CALIFORNIA SOILS DESCRIBED BY CLASSES 
 
 CLAY SOILS. ADOBE SOILS 
 
 In the following general description of the soils arranged by 
 classes, the average physical analysis of each soil is given in the class 
 to vi^hich it belongs. At the foot of each table is given the highest, 
 lowest, and average amount of fine gravel, coarse sand, medium sand, 
 fine sand, very fine sand, silt and clay in the soils described. 
 
 A careful study of the table will therefore show wherein each 
 soil is modified by local conditions, such as the nature of the subsoil, 
 concerned. These affect the general properties of the soil and show 
 whether it is light or heavy, easy or difficult to drain and cultivate, or 
 whether it is plastic, puddles, etc. The local productiveness of each 
 soil is modified by local conditions, uch as the nature of the sub-soil, 
 where the soil occurs, local topography, climate, etc. The conditions 
 are given in broad outline with each soil and the reader is referred to 
 the annual reports of the U. S. Bureau of Soils for extended local 
 details. 
 
 Under the present system of classification the commercial value 
 of the soils can be seen in the field in the character of the soil and 
 from its relation to natural vegetation and artificial crops. It can be 
 mapped independently of a knowledge of the geology of the region, 
 or of the exact chemical and physical character of the soil. It is now 
 possible to map in the field the areas and distribution of the types, 
 leaving the work of geologic origin, and minute differences to be 
 noted by the soil chemist and physicist in their laboratory investiga- 
 tions . The object of a soil survey, whether of an acre or of a county, 
 is to provide an accurate basis for the adaptation of soils to crops. 
 
 CORRELATION. The soils of different areas having the same tex- 
 ture and composition, and the same crop value (the local climatic 
 variations being considered), are given the same name, no matter 
 what part of the state they occur in. This simplifies the nomenclature 
 and calls attention to the similarities of soils and to the possibilities 
 of extending industries into new localities. While no attempt is made 
 as yet by the Government to correlate the soils of the different states 
 except in a very general way, certain close similarities are recognized 
 by all: and soil names are carried across the boundaries of a state 
 in adjoining states. The Fresno sand is the equivalent of the Colo- 
 rado sand in the lower Arkansas Valley and corresponds very closely 
 in texture and crop value to the truck soils of the Atlantic Coast. 
 The Fresno fine sand is the equivalent of the Laurel fine sand of 
 Colorado; the Fresno fine sandy loam, to the Marshall silt loam of 
 Colorado and to the Weber fine sandy loam of Utah; the Maricopa 
 
California Soils Described by Classes 109 
 
 gravelly loam, to the Bingham gravelly loam of Utah and the Bridger 
 gravelly loam of Oregon; and the Maricopa sandy loam is the equiv- 
 alent of the Bridger loam of Oregon, etc. 
 
 CHANGES IN NAMES. The U. S. Bureau of Soils with increased 
 knowledge of soils gained as the surveys progress have found it nec- 
 essary to make certain readjustments in the classifications and names. 
 Some of the names that appeared on the soil maps when published 
 were provisional only, awaiting investigation and comparison. These 
 changes in names have been carefully noted to date in each soil 
 description, and should be noted on the government maps where 
 persons have copies. 
 
 CLAY 
 Fine Coarse Medium Fine Very 
 gravel sand sand sand fine sand Silt Clay 
 
 Alvlso 0.0 0.4 0.7 2.3 0.4 52.3 44.5 
 
 Dunnig-an 0.1 0.5 0.6 2.3 1.1 30.8 64.5 
 
 Esparto 0.0 0.3 0.9 5.9 7.6 43.4 41.6 
 
 Galveston 0.6 2.0 2.1 6.4 12.1 31.5 45.2 
 
 Imperial 0.1 0.5 0.6 3.5 6.3 36.7 49.1 
 
 Livermore 0.3 0.8 1.1 6.5 16.3 44.5 30.4 
 
 Sacramento 0.0 0.5 0.7 3.4 1.8 41.0 52.7 
 
 Sutter 1.1 4.6 4.3 9.9 11.2 29.6 39.2 
 
 Tehama 2.1 2.0 1.8 4.9 18.5 34.9 35.5 
 
 Yolo 0.0 0.1 0.1 0.9 7.6 50.9 40.4 
 
 Willows 0.5 0.4 0.6 3.2 7.4 45.1 43.4 
 
 Highest 2.1 4.6 4.3 9.9 18.5 52.3 64.5 
 
 Lowest 0.0 0.1 0.1 0.9 1.1 29.6 34.4 
 
 Average 0.4 1.1 1.2 4.5 8.2 40.1 44.1 
 
 Soils that contain over 50 per cent of silt and clay together are 
 called clay soil if the clay content is over 30 per cent. They vary 
 widely according to the rocks of the drainage district in which they 
 occur, and in the iron and organic matter present. They are the 
 reverse of the sand soils in character, admitting air and water slowly. 
 Heavy, compact and silty, they become plastic and sticky when wet, 
 with a tendency to puddle, and are retentive of moisture. This makes 
 them cold and hard to till. They dry slowly, forming a hard crust, 
 lumps and clods, and crack badly, and are hard on plant roots. The 
 natural drinage is generally deficient on account of the low positions 
 occupied by the soils. On the other hand these soils are rich in plant 
 food, and under-drainage removes excess of moisture and promotes 
 aeration and warmth. There is a point between wetness and dryness 
 where clay soils crumble quite readily and are friable when carefully 
 handled, and they should be tilled only at such a time as far as pos- 
 sible. They sufifer from the extremes of both wet and dry weather 
 and are expensive to cultivate. Clay is an extremely fine soft powder 
 produced by the chemical as well as mechanical decomposition ot 
 various minerals. It consists of particles from 0.005 to 0.000 milli- 
 meters in diameter. When wet, clay swells up into a sticky plastic 
 substance which shrinks in drying to a tough coherent mass. It is 
 very retentive of water, gases, and minerals in solution, and presents 
 such a large surface for the plant rootlets to feed on that the clay 
 soils are sometimes called strong soils by the farmer. Clay also acts 
 as a cement which holds the other ingredients together and renders 
 
110 Soils of California 
 
 the soil hard to till. Silicate of alumina is always present in large 
 quantities and serves to flocculate the soil particles. Without clay the 
 sand would collapse into close packed grains as soon as it became 
 dry, and loose tilth would be impossible. 
 
 ALVISO CLAY. Mapped in the Pajaro area. Drab, six feet deep. 
 OCCURS on tidal flats. ORIGIN: alluvial. CROPS: Crops of 
 barley have been grown where protected by levees and washed with 
 fresh water. 
 
 DUNNIGAN CLAY. Mapped in the Woodland area. Yellow to dark 
 gray or black, three feet deep. SUBSOIL: Yellow or brown clay. 
 OCCURS on long, narrow areas, in depressed or low flat areas. Lo- 
 cally called "Hogwallow land" in Yolo and Colusa districts. ORIGIN: 
 Fine wash from the flood waters of the basin and wash from higher 
 soils. CROPS: Unfit for cultivated crops without underdrainage. 
 Generally alkaline. 
 
 CAPAY CLAY. Mapped in the Woodland area. No analysis re- 
 ported, gray to gray brown, sometimes tinged with red, three feet 
 deep. SUBSOIL: Dense reddish to yellowish brown clav. OCCURS 
 on low ground, flat, broken by sloughs and creeks. ORIGIN: Recent 
 alluvial. CROPS: Grain, hay, alfalfa where well drained; alkali 
 where the drainage is imperfect. 
 
 ESPARTO CLAY. Mapped in the Woodland area. Yellow to dark 
 brown, two to three feet, drainage generally good. SUBSOIL: 
 Clay or clay loam. OCCURS on broad slopes approaching the hills; 
 flat to easy slopes. ORIGIN: Recent alluvial. CROPS: Dry farmed 
 to grain, alfalfa, general farm crops, sugar beets; adapted to sor- 
 ghum, Egyptian corn, peaches, apricots, almonds, figs, grapes. 
 GALVESTON CLAY. Mapped in the Los Angeles and San Jose 
 area. Black to brownish gray, over six feet deep, often saturated 
 -'•ith salt water. SUBSOIL: Blue or black mud, gray or bluish 
 gray silt. OCCURS around San Francisco Bay, on the coast in 
 coastal swamps, in river channels. ORIGIN: Product of lacustrine 
 or swamp deposits derived from the slack waters of tidal flats, 
 sloughs and estuaries, and silt deposited by rivers in flood times, 
 combined with swamp vegetation. CROPS: Owing to the presence 
 of large amount of alkali salts it has no agricultural value under 
 present conditions of drainage. 
 
 IMPERIAL CLAY. Mapped in the Imperial and Indio areas. Slate 
 colored, micaceous, six feet. SUBSOIL: A mixture of clay silt and 
 fine sand. OCCL^RS in low level places, sometimes hummocky. 
 ORIGIN: Mixed sediments from mountains and rivers. CROPS: 
 Too strong in alkali except for the most alkaline resistant crops, 
 such as sorghum, barley, Egyptian cotton, rice. 
 
 LIVERMORE CLAY. Mapped in the Livcrmore area. Dark 
 chocolate brown, thirty to thirty-six inches. SUBSOIL: Gray brown 
 Hay loam. OCCURS on valley bottoms, poorly drained. ORIGIN: 
 Colluvial and alluvial. VEGETATION: Valley oak. CROPS: Hay, 
 grain. 
 
 SACRAMENTO CLAY. Mapped in the Marysville area. Black, six 
 feet deep. Locally called "Tulc Land," water logged. SUBSOIL: 
 Clays or hardpan. OCCURS in slough basins, overflowed areas, 
 
Cazifoenia Soils Described by Classes 
 
 111 
 
 rarely free from standing water. ORIGIN: From material carried 
 in suspension by river flood waters, with annual additions. CROPS: 
 Too expensive and unprofitable to drain under present methods. Often 
 alkaline. 
 
 SACRAMENTO HEAVY CLAY. Mapped in the Woodland area. 
 Blue black to drab, six feet, high per cent of organic matter. SUB- 
 SOIL: Similar. OCCURS on floor of basins; flat with slight slope. 
 ORIGIN: Wash from higher soil bodies. CROPS: Grain; where 
 protected from overflow adapted to grain, sorghum, Egyptian corn, 
 hay and other forage crops. 
 
 SUTTER CLAY. Mapped in the Marysville area. Brown, few inches 
 deep. SUBSOIL: Sticky, yellowish clay. ORIGIN: Material washed 
 from the Marysville Buttes; from the finer material from the 
 weathering of volcanic rocks. CROPS: Grain in wet years. 
 TEHA.MA CLAY. Mapped in the Red BluflF area. Gray brown to 
 yellowish brown; adobe-like when wet; when dry is hard and cracks 
 and checks; thirty-six to forty-eight inches. SUBSOIL: Variable. 
 OCCURS from gently rolling to flat and depressed areas. ORIGIN: 
 Wash from higher lying soils. CROPS: Grazing. 
 
 YOLO CLAY. Mapped in the Woodland area. Brown, six feet deep, 
 lacks organic matter. SUBSOIL: Lighter color, silty clay. OCCURS 
 in irregular bodies; gently sloping from streams; low flat areas 
 ORIGIN: Alluvial. CROPS: Barley, alfalfa; adapted to tree fruits, 
 grapes, beets and other field crops. 
 
 WILLOWS CLAY. Mapped in the Colusa and Woodland areas. 
 Reddish, yellowish yellowish brown to drab; three to six feet deep; 
 drainage poor. SUBSOIL: Clay, hardpan. OCCURS on nearly 
 level valley plains, depressions, drainage troughs. ORIGIN: Allu- 
 vial. CROPS: Grazing. Generally alkaline. 
 
 CLAY ADOBES very 
 
 Fine Coarse Medium Fine fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Alamo 0.2 3.4 4.2 10.4 8.3 51.9 21.9 
 
 Altmont 0.1 0.9 1.4 4.9 10.4 48.1 34 1 
 
 Arnold 0.1 2.1 2.3 10.5 4.9 37.4 42 5 
 
 Capay 0.2 1.8 2.3 10.9 16.9 44.5 23.2 
 
 Daulton 2.0 4.5 2.8 6.7 6.1 25.3 52.7 
 
 Diablo 0.3 1.2 1.6 8.4 19.1 38.5 31.0 
 
 Dublin 0.1 0.6 0.8 5.6 17.6 30.1 45.0 
 
 Hanford 0.5 2.6 2.5 8.5 8.3 41.5 35.8 
 
 Media 2.3 7.1 4.8 10.2 10.3 34.7 30.6 
 
 Norman 0.4 1.2 1.1 2.8 0.9 55.6 37.4 
 
 Pleasanton 1.5 4.5 3.6 10.4 18.6 28.3 33 2 
 
 Portersville .... 1.3 5.0 3.2 5.7 6.7 34.4 43.5 
 
 Sacramento 0.0 0.4 0.3 4.0 3.0 46.9 46 3 
 
 Salinas gray .... 1.1 3.6 4.0 10.3 10.6 37.9 30 7 
 
 San Joaquin .... 0.5 2.4 1.8 10.4 11.7 32.0 41 4 
 
 Santa Rita 0.0 0.1 0.5 1.9 12.3 43 9 413 
 
 Sites 0.0 0.8 1.8 5.3 5.9 37.2 49 
 
 Stockton 0.5 1.0 0.8 4.0 7.8 37.5 48 5 
 
 Vallecitos 0.0 0.5 0.5 3.7 21.9 37.8 35 6 
 
 Vina 1.5 2.6 2.2 4.3 9.0 33.3 46.9 
 
 Willows 0.1 1.2 0.8 3.9 4.7 37.7 55.7 
 
 Highest 2,3 7.1 4.8 10.9 21.9 55.6 55 7 
 
 Lowest 0.0 0.1 0.3 1.9 0.9 25.3 219 
 
 Average 0.6 2.2 2.1 6.8 9.4 39.3 39.4 
 
112 Soils op Califobnia 
 
 The Mexican "adobe" is an unburnt brick dried in the sun, and 
 in common use in all western regions where the rainfall is small, 
 the name being derived from the Spanish "adobar," meaning to "daub 
 or plaster." The term was naturally applied to the clayey soils 
 suitable for making the "bricks without straw" or burning. All the 
 adobe soils are clay soils that have typical qualities, as shown by a 
 peculiar stickiness, or adhesiveness, when wet, and checking into 
 cubes when dry. 
 
 COMMON PROPERTIES: The table shows that they contain from 
 22 to 36 per cent of clay and 25 to 56 per cent of silt. That is, over 
 80 per cent of their material consists of the Hnest particles of which 
 soils are composed. This makes them dense, close and compact; 
 slow to absorb water, but retain water tenaciously; impervious to 
 more water when thoroughly wet; plastic, sticky, or waxy; puddling 
 when wet; tough, heavy and putty-like, and hard to cultivate. They 
 dry out slowly, baking on exposure, and become hard and compact 
 when dry. They expand when wet, and shrink while drying, causing 
 the soil to check and crack. When the sand contents are above 
 normal, and when they are well drained, they become fairly friable. 
 They are generally dark gray in color, with occasional brown 
 grays and black, and occur in irregular bodies at the base of foot- 
 hills, on low level plains, and in narrow valleys, or in river depres- 
 sions that are subject to overflow. Most of them are used only for 
 grazing, hay or grain, but with irrigation, drainage and thorough 
 cultivation, are adapted to alfalfa, grain and general farm crops, 
 and locally to vines and fruit trees. 
 
 ALAMO CLAY ADOBE. Mapped in the Marysville area. Gray 
 to black, two to three feet deep. SUBSOIL: Red hardpan. OCCURS: 
 Low, subject to overflow. ORIGIN: Sedimentary and alluvial. Pleis- 
 tocene lake deposits altered and added to by wash from higher land. 
 CROPS: Grazing, hay, grain, some grapes and fruits. 
 
 ALTAMONT CLAY ADOBE. Mapped in the Livermore area. 
 Brown to chocolate, three to five feet, sticky when wet but dries 
 loose and friable. SUBSOIL: Yellow brown clay loam. OCCURS 
 on high hills. ORIGIN: Residual, from Tertiary sandstones and 
 shales. CROPS: Grain and hay. 
 
 ARNOLD CLAY ADOBE. Mapped in the Modesto-Turlock area. 
 Purplish brown, black to dark gray, fifteen inches to three feet deep. 
 OCCURS on level plains, and covering hillsides. ORIGIN: Lacus- 
 trine, and alluvial weathering of andesitic tuf¥. CROPS: Dry farming 
 and pasture. 
 
 CAPAY CLAY ADOBE. Mapped in the Woodland area. Gray to 
 dark brown, three feet deep, variable in texture. SUBSOIL: Clay, 
 yellow to reddish brown. OCCURS: Flat, low levels of the plains. 
 CROPS: Grain and hay. Frequently alkaline. 
 
 DAULTON CLAY ADOBE. Mapped in the Madera area. Red, 
 six feet. SUBSOIL: Granitic and quartz rocks. ORIGIN: Residual. 
 CROPS: Grain. 
 
 DIABLO CLAY ADOBE. Mapped in the Livermore area. Dark 
 brown or gray to black, contains an excess of lime, twenty-four to 
 
Califobnia Soils Descbibed by Classes 113 
 
 forty inches. SUBSOIL: Bedrock. OCCURS on the Diablo hills 
 and foothills. Fossil oyster shells (Astiga titan) are often found on 
 some of the peaks and ridges. ORIGIN: Residual, modified by col- 
 luvial from the Tertiary limestones and calcareous sandstones and 
 shales. Small amount of alkali. CROPS: Dry farmed to hay and 
 grain. 
 
 DUBLIN CLAY ADOBE. Mapped in the Livermore area. Slate 
 to black color, twelve to fifteen inches deep. SUBSOIL: Black clay. 
 OCCURS on valley bottoms, nearly level, poorly drained. ORIGIN: 
 Colluvial wrash from hills. CROPS: Dry farmed to hay and grain. 
 
 HANFORD CLAY ADOBE. Mapped in the Sacramento area as 
 Salinas gray adobe. Dark gray to nearly black, considerable fine to 
 coarse sand. SUBSOIL: Sand, clay, volcanic mud flows. OCCURS 
 as irregular bodies, base of foothills, upper valley margins, flat 
 topped tablelands. ORIGIN: From the weathering and breaking 
 down of interstratified beds of Pleistocene clay, ash and volcanic 
 muds, modified by stream wash. CROPS: Grazing, grain, hay. 
 VALLEY PHASES: Three feet deep, gray to black silt. SUBSOIL: 
 Sandy adobe or hardpan, in local depressions and sinks. 
 MEDIA CLAY ADOBE. Mapped in the Madera area. Red, three 
 to six feet. SUBSOIL: Partially decomposed granitic rock. OCCURS 
 on rolling lands. ORIGIN: Colluvial and alluvial. CROPS: Grazing. 
 NORMAN CLAY ADOBE. Mapped in the Colusa area. Dark 
 brown to black: moderately friable when moisture conditions are 
 favorable. SUBSOIL: Clay, clay loam, yellowish to bluish. OCCURS 
 in minor depressions of gently sloping valley plains; in narrow 
 valleys in foothills in irregular bodies. ORIGIN: Alluvial from the 
 sediments of intermittent streams, and wash of more elevated soils. 
 CROPS: With irrigation, drainage and thorough cultivation, alfalfa, 
 grain and general farm crops. 
 
 PLEASANTON CLAY ADOBE. Mapped in the Livermore area. 
 Dark brown, carries angular gravel, eighteen to thirty-six inches. 
 SL^BSOIL: Red yellow clav. OCCURS on hills and narrow ridges. 
 ORIGIN: Sedimentary. CROPS: Grazing, hay. 
 
 PORTERSVILLE CLAY ADOBE. Mapped in the Portersyille 
 and Madera areas. Black, six feet deep, small rock fragments, lime 
 concretions, locally called "dry bog land," high per cent of organic 
 matter. SUBSOIL: Similar. OCCURS at lower elevations than 
 the Portersville clay loam adobe. ORIGIN: Largely colluvial, wash 
 from the higher slopes. CROPS: Dry farming to grain. Little 
 alkali. 
 
 SACRAMENTO CLAY ADOBE. Mapped in the Woodland area. 
 Gray to black, two to three feet deep, poorly drained. SUBSOIL: 
 Dark brown, j'ellow brown clay. OCCURS on low overflowed flat 
 areas. ORIGIN: Alluvial. CROPS: Pasture and grain. 
 SALINAS GRAY ADOBE. Mapped in the San Jose and lower 
 Salinas Valley areas. That mapped as Salinas gray adobe in the 
 San Bernardino and Sacramento areas has been reclassified as Han- 
 ford clay adobe. Light to dray gray, nearly black, texture variable, 
 one to six feet deep; drainage fair, well supplied with organic matter. 
 
114 Soils of California 
 
 SUBSOIL: Sandy loam, clay loam, hardpan, disintegrated granite. 
 OCCURS on smooth or slightly sloping land, on higher elevations, 
 foothills, in narrow irregular bodies. ORIGIN: Wash from granite 
 hills and shaly sandstones, from Jurassic formations, primarily 
 residual. CROPS: Grain, alfalfa, barley in the lower Salinas Valley; 
 peaches, prunes, grapes at San Jose. Some alkali where poorly 
 drained. 
 
 SAN JOAQUIN CLAY ADOBE. Mapped in the Portersville area. 
 Dark red, eighteen inches to six feet. SUBSOIL: Dense red hardpan. 
 OCCURS in low depressions, hog wallow depressions, no drainage. 
 ORIGIN: Lacustrine of Pleistocene age. CROPS: Grazing and dry 
 farming. 
 
 SANTA RITA CLAY ADOBE. Mapped in the Livermore area. 
 Dark gray, never puddles but checks to a friable surface easily culti- 
 vated, three to six feet. SUBSOIL: Slaty to black heavy clay. 
 OCCURS on flat, poorly drained land, some hog wallows. ORIGIN: 
 On site of a former shallow lake, then a tule swamp. Alkali variable. 
 CROPS: Hay, grain, sugar beets. 
 
 SITES CLAY ADOBE. Mapped in the Woodland area. Red brown 
 to gray, eighteen inches to three feet. SUBSOIL: Red clay, white 
 or green calcareous clay, clay loam. OCCURS on rolling, hilly 
 land; steep, dissected by narrow valleys. ORIGIN: Residual and col- 
 luvial. CROPS: Pasture, grain, hay. 
 
 STOCKTON CLAY ADOBE. Mapped in the Marysville, Modesto- 
 Turlock and Stockton areas. Chocolate browns to blacks, one to 
 five feet deep, drainage deficient. SUBSOIL: Light yellow silty 
 clay. OCCURS in irregular shaped bodies in low level places. 
 ORIGIN: From a great variety of rocks, modified by ancient Pleis- 
 tocene sediments. CROPS: Alfalfa, grain, forage, vines, fruit trees. 
 Generally free from alkali. 
 
 VALLECITOS CLAY ADOBE. Mapped in the Livermore area. 
 Red brown, thirty to thirty-six inches. SUBSOIL: Yellow brown 
 clay. OCCUR.S on narow ridges and in deep ravines. ORIGIN: 
 Residual, from metamorphic rocks. CROPS: Grazing, hay, grain. 
 VINA CLAY ADOBE. Mapped in the Red Bluf¥ area. Brown, pud- 
 dles but friable with tillage, two to six feet. SUBSOIL: Clay loam. 
 OCCURS in broad tracts below terraces; level, overflowed, drainage 
 sluggish. ORIGIN: Alluvial. VEGETATION: Valley oaks, wild 
 oats. CROPS: Grain, adapted to stone fruits. 
 
 WILLOWS CLAY ADOBE. Mapped in the Colusa and Woodland 
 areas. Dark chocolate brown, three feet deep, drainage poor. SUB- 
 SOIL lighter in texture. OCCURS in irregular shaped, elongated 
 bodies, occupies draws and depressions in valley plains. ORIGIN: 
 Wash from foothills and from other soils. CROPS: Dry farming. 
 When drained, adapted to sugar beets, alfalfa and general farm crops. 
 Apt to be alkaline. 
 
 SILTY CLAY ADOBE 
 
 KIRKWOOD SILTY CLAY ADOBE. Mapped in the Red BluflF 
 area. Dark gray to black, smooth texture, very sticky, six feet and 
 over. SUBSOIL: Same, lighter textured. OCCURS on level or 
 
Califobnia Soils Described by Classes 115 
 
 gently sloping plains. ORIGIN: Wash from the Red Bluff formation 
 and from adjacent soils. Not extensive or important. CROP: Dry 
 farmed to grain. P'ine gravel, 1.1; coarse sand, 1.7; medium sand, 1.6; 
 fine sand, 4.0; very fine sand, 6.0; silt, 52.1; clay, 33.4. This soil, as 
 the name shows, is a clay adobe containing an excess of silt. 
 
CHAPTER XVI 
 
 SILTY CLAY. 
 
 SILTY CLAYS. CLAY LOAMS. GRAVELLY CLAY 
 
 LOAMS. CLAY LOAM ADOBES. SILTY 
 
 CLAY LOAMS. LOAM ADOBES. 
 
 STONY CLAY LOAMS. 
 
 Very 
 Fine Coarse Medium Fine fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Pajaro 0.0 0.3 0.6 2.4 1.5 65.3 29.0 
 
 Sacramento 0.5 0.9 0.7 4.7 3.8 55.2 33.6 
 
 Yolo 0.0 0.1 0.1 3.2 5.0 58.3 33.5 
 
 Average 0.2 0.4 0.5 3.4 3.4 59.6 32.1 
 
 The silty clays are between the silt loams and the clays in 
 character, there being about the same amount of silt and more clay 
 than in the silt loams, and less of the fine sands. They are smooth 
 and vary from light to heavy texture. Being compact, they puddle 
 when wet and bake and check on drying. When well drained and 
 well cultivated, they break into a friable loam and become mellow. 
 They are easily cultivated if worked at the most favorable time so 
 far as their moisture contents are concerned. 
 
 PAJARO SILTY CLAY. Mapped in the Pajaro area. Light yellow 
 or drab, high per cent of humus; twelve to thirty-six inches. SUB- 
 SOIL: Dark loam, silt loam. OCCURS in old channels, in low 
 depressions, in river bottoms. ORIGIN: From weathered shales 
 deposited by flood waters of streams. CROPS: Adapted to many 
 farm crops; wheat, barley, sugar beets, beans. 
 
 SACRAMENTO SILTY CLAY. Mapped in the Colusa and Wood- 
 land areas. Black to dark gray; six feet. SUBSOIL: Light colored 
 silty and sandy sediments, heavy clay adobe. OCCURS in irregular, 
 elongated bodies, nearly level. ORIGIN: Old stream flood plains 
 sediments, mixed with wash from adjacent soils. CROPS: Dry 
 farming and grain, wheat, barley; with artificial drainage and inten- 
 sive cultivation, adapted to sorghum, broom corn, Egyptian corn, 
 alfalfa and sugar beets Sometimes alkali is found in the large 
 depressions. 
 
 YOLO SILTY CLAY. Mapped in the Woodland area. Chocolate 
 brown, good drainage, three to six feet. SUBSOIL: Brown clay 
 loam, clay. OCCURS: Flat or slightly undulating along creek 
 courses. ORIGIN: Alluvial. CROPS: Grain, alfalfa, wine and 
 raisin grapes; adapted to sugar beets, sorghum, Egyptian corn, 
 vegetables, etc. 
 
SiLTT Clay 117 
 
 CLAY LOAMS 
 
 Very- 
 Fine Coarse Medium Fine fine 
 gravel sand sand sand sand Silt Clay 
 
 Arbuckle 1.6 3.4 2.9 9.2 11.3 45.9 25.8 
 
 Capay 0.2 1.8 2.3 10.9 16.9 44.5 23.2 
 
 Daulton 1.5 1.9 1.9 11.3 34.0 24.3 25.2 
 
 Dublin 1.3 2.4 1.7 11.6 10.7 47.7 24.4 
 
 Esparto 0.0 1.1 3.1 12.7 11.4 40.8 30.3 
 
 Fresno 0.4 2.3 2.5 8.0 22.1 40.4 24.2 
 
 Gila 0.0 0.6 1.1 6.0 11.9 42.2 37.5 
 
 Hanford 0.2 0.7 0.5 6.9 18.1 46.3 27.0 
 
 Imperial 0.2 0.2 0.2 3.2 7.6 48.1 35.7 
 
 Lewis 0.7 2.3 1.9 8.3 14.4 49.8 22.3 
 
 Livermore 0.4 1.5 1.6 9.9 21.8 41.1 23.T 
 
 Madera 0.8 4.5 3.7 10.1 11.7 40.6 28.2 
 
 Marcuse 0.2 3.0 3.5 14.4 14.5 41.3 23.1 
 
 Oxnard 0.3 1.0 1.1 13.9 18.7 36.9 21.7 
 
 Placentia 0.2 0.7 0.6 4.1 21.6 43.9 28.8 
 
 Sacramento 0.3 0.8 0.5 2.5 6.3 40.3 49.7 
 
 San Joaquin 1.9 4.9 3.6 10.7 24.6 29.1 25.2 
 
 Sierra 2.7 6.1 3.3 9.0 8.1 41.0 24.1 
 
 Stockton 0.1 1.4 1.3 12.1 14.5 48.3 21.8 
 
 Tassajero 0.0 0.2 0.9 10.4 28.8 33.3 26.4 
 
 Vina 0.4 1.0 1.4 7.3 22.3 47.9 19.2 
 
 Willows 0.0 0.5 0.8 9.3 15.0 47.4 26.9 
 
 Yolo 0.0 1.9 3.9 16.6 16.6 42.1 19.0 
 
 Highest 2.7 6.1 3.9 16.6 34.0 49.8 49.7 
 
 Lowest 0.0 0.2 0.2 2.5 7.6 24.3 19.0 
 
 Average 0.5 1.5 1.5 9.5 19.7 41.9 26.7 
 
 Soils containing 50 per cent of silt and clay are called clay loams, 
 if they contain from 20 to 30 per cent of clay, or less than SO per 
 cent of silt. The average of the analyses show that the California 
 clay loams contain about 42 per cent of silt and 27 of clay, with 
 nearly 20 per cent of very fine sand and 10 of fine sand. They are 
 rather heavy, being a little heavier than silt loam but not so heavy 
 or sticky as adobe, yet stiff and compact. They do not crack w^hen 
 dry in the manner true adobe does. They readily absorb and retain 
 water and are sticky and tenacious when wet. The clay loams require 
 very heavy farm equipment, the cultivation being limited to a some- 
 what narrow range of moisture conditions. On the other hand, they 
 are friable and mellow and easily cultivated under favorable moisture 
 upon local conditions of drainage, climate and careful management, 
 conditions such as when well drained. They arc apt to contain 
 alkali in spots, especially in low poorly drained areas, and are to be 
 feared on this account more than the other loams. The crop depends 
 
 ALTAMONT CLAY LOAM. Mapped in the Livermore area. Dark 
 brown, carries fragments of shale, 18 to 30 inches. SUBSOIL: Yel- 
 low clay loam. OCCURS on steep hills. ORIGIN: Residual from 
 shales. VEGETATION: Live oak, poison oak, maple, shrubs. 
 CROPS: Grazing, hay, grain. 
 
 ARBUCKLE CLAY LOAM. Mapped in the Woodland area. Brown 
 or gray brown; 24 to 36 inches deep, small percent of gravel; drain- 
 age variable. SUBSOIL: Yellowish brown clay loam; clay. OC- 
 CURS in large irregular bodies, on flat to gentle slopes. ORIGIN: 
 from the deposits of finer material carried by the foothill streams, 
 
118 Soils of Califobnia 
 
 modified by later wash from the more elevated surrounding soil 
 bodies. CROPS: Wheat, barley, wine and raisin grapes; hardy iruits; 
 general farm crops; dairy farming. 
 
 CAPAY CLAY LOAM. Mapped in the Woodland area. Gray to 
 brown, six feet deep, contains tine gravel, well drained. SUBSOIL: 
 Heavy, red brown clay. OCCURS along small intermittent 
 streams. ORIGIN: Recent alluvial. CROPS: Grain, almonds, grapes. 
 Free from alkali where well drained. 
 
 DAULTON CLAY LOAM. Mapped in the Madera area. Brown, 
 two to six feet. SUBSOIL: Quartz, schist, granitic rocks. OCCURS 
 on rolling foothills. ORIGIN: residual. CROP: Grain. 
 DUBLIN CLAY LOAM. Mapped in the Livermore area, Brown to 
 black, one to four feet. SUBSOIL: Loam. OCCURS on slopes at the 
 foot of hills. ORIGIN: Colluvial and alluvial. CROPS: Dry farmed 
 to grain; irrigated — peaches, pears, prunes. 
 
 ESPARTO CLAY LOAM. Mapped in the Woodland area. Yellow 
 to yellow brown; three feet deep. SUBSOIL: Silty clay; clay loam. 
 OCCURS: Marks the position of present or former streams; on nar- 
 row or of expansive ridges, slightly elevated above the surrounding 
 level. ORIGIN: Recent alluvial. CROPS: Grain, alfalfa, apricots, 
 peaches, figs, almonds, grapes; adapted to beans, beets and general 
 farm crops. Free from alkali. 
 
 FRESNO CLAY LOAM. Mapped in the Madera area. Brown to 
 black, two to six feet. SUBSOIL: Bluish hardpan. OCCURS: Level, 
 marked by sloughs, drainage poor. ORIGIN: Alluvial. Carries some 
 alkali. CROPS: Local — alfalfa, prunes, plums, pears. 
 GILA CLAY LOAM. Mapped as Imperial loam in the Yuma 
 California area. Chocolate brown, three to six feet deep; contains 
 considerable organic matter. SUBSOIL: Sand, clay. OCCURS: Gen- 
 erally level, in bottom lands, above overflow and quite well drained. 
 ORIGIN: Deposited directly from river waters. CROPS: Under 
 careful management should prove valuable for cereals, and such sum- 
 mer annuals as Kafifir, Egyptian, and Indian corn, millet, sorghum and 
 all crops not requiring intertillage. Contains from 0.2 to more than 
 3 per cent alkali, hence more to be feared than others of the series. 
 
 HANFORD CLAY LOAM. Mapped in the Madera area. Mapped 
 as Santiago silt lo?m in the San Bernardino and San Gabriel areas; 
 and as Oxnard silt loam in the BakersField area. Chocolate brown 
 to black; contains high per cent of organic matter, three to six feet 
 deep. SUBSOIL: Sand, fine sandy loam. OCCURS: Level, low flat 
 tracts cut by sloughs and remnants of former stream channels. ORI- 
 GIN: Alluvial. CROPS: Alfalfa, grain, small fruits. Generally free 
 from injurious quantities of alkali. , 
 
 IMPERIAL CLAY LOAM. Mapped as Imperial loam in the Im- 
 perial area. Reddish, contains considerable organic matter. SUB- 
 SOIL: Clay loam; clay. OCCURS: Smooth and level. ORIGIN: 
 River sediments deposited while the area was submerged, or from 
 overflow waters. CROPS: Adapted to wheat, barley, sugar beets, 
 Kaflir corn, Egyptian corn, sorghum, alfalfa if not pastured. Gen- 
 erally some alkali, heavy in spots. 
 
SiLTY Clay 119 
 
 LEWIS CLAY LOAM. Mapped in the Portersville area. Grayish, 
 six feet deep; poorly drained. SUBSOIL: Gravel, hardpan. OCCURS 
 in long narrow strips, uneven, lowland. ORIGIN: Alluvial, hne sedi- 
 ments deposited by creeks in body of quiet water. CROPS: Graz- 
 ing only. Alkali always present. 
 
 LIVERMORE CLAY LOAM. Mapped in the Livermore area. 
 Gray brown, bakes, checks, three to four feet. SUBSOIL: Yellow 
 brown clay loam. OCCURS: Level, well drained. ORIGIN: Colluvial 
 and alluvial. VEGETATION: Valley oak. CROP: Grain, grass. 
 MADERA CLAY LOAM. Mapped in the Madera area. Brown, three 
 to six feet. SUBSOIL: Red hardpan. OCCURS along the smaller 
 stream courses. ORIGIN: Colluvial and alluvial. CROPS: Grain, 
 adapted to fruit locally. 
 
 MARCUSE CLAY LOAM. Mapped in the Marysville area: Gray 
 to black, two to three feet deep. SUBSOIL: Reddish, sticky loam. 
 ORIGIN: Alluvial, deposited by overflow waters. CROPS: Grazing 
 during dry season. Alkali generally present in dangerous quantities. 
 OXNARD CLAY LOAM. Mapped as Oxnard loam in the Los An- 
 geles, San Jose and Ventura areas. Dark brown to black, two to ten 
 feet, rich in organic niatter, generally well drained. Stony phase 
 contains gravel, slate fragments and granitic pebbles. SUBSOIL: 
 same but heavier and more compact; gravelly soil. OCCURS: Gently 
 sloping plain, in irregular-shaped bodies; level, on slightly depressed 
 parts of valleys. ORIGIN: From slate and argillaceous sandstone and 
 closely allied rocks; a mixture of the lighter soils derived from moun- 
 tain waste, with the heavier alhivial and lacustrine deposits of the 
 valley. CROPS: Lima beans, alfalfa, fruit, barley, corn, truck, grapes, 
 strawberries, raspberries, onions, tomatoes, walnuts, lemons. Alkali 
 present in appreciable quantities in low and poorly drained areas. 
 PLACENTIA CLAY LOAM. Mapped as Placentia loam in the San 
 Bernardino area. Reddish brown, micaceous, six feet deep, consider- 
 able fine sand, poorly drained. OCCURS: Level, smooth. ORIGIN: 
 Washings from the Placentia sandy loam. CROPS: Alfalfa. Some 
 alkali due to seepage. 
 
 SACRAMENTO CLAY LOAM. Mapped in the Stockton area. Dark 
 to black, high per cent of organic matter, two to thirty feet deep, 
 drainage poor. SUBSOIL: Light yellow, fine silty loam, fine sandy 
 loam. OCCLTRS: Level, slightly inclined, grades into peats, adobes 
 and loams. ORIGIN: River silts mixed with alluvial organic matter 
 of the tidal fresh water marshes. CROPS: Alfalfa, redtop, rye grass, 
 timothy, wheat, barley, oats, beans, vegetables, grains; peaches, apri- 
 cots, pears and cherries where well drained. Generally free from 
 
 SAN JOAQUIN CLAY LOAM. Mapped in the Madera area. Red 
 to red brown; two to four feet. SUBSOIL: Red hardpan. OCCURS: 
 In small local areas, hogwallows. ORIGIN: Colluvial and alluvial. 
 CROP: Grain. 
 
 SIERRA CLAY LOAM. Mapped in the Sacramento area. Light 
 to deep red; three feet deep, drainage good. SUBSOIL: Bedrock. 
 OCCURS: Prevailing type of the upper foothill region in the Sacra- 
 mento area; outcropping ledges. ORIGIN: Weathering in place of 
 underlying amphibolite diabase and limestone. CROPS: Grains, hay, 
 
120 Soils of Califobnia 
 
 grapes; deciduous fruits; olives. NATIVE VEGETATION: Oak, gray 
 leaf and yellow pine, shrubs. 
 
 STOCKTON CLAY LOAM. Mapped in the xModesto-Turlock area. 
 Yellow, 18 to 24 inches deep. SUBSOIL: Yellow adobe, silly fine 
 sandy loam, hardpan. OCCURS: Smooth, flat, gently sloping flood 
 plains. ORIGIN: Deposited by local streams. CROPS: Grain farm- 
 ing, alfalfa, grapes, adapted to peaches, prunes, figs, berries and gar- 
 den truck. Free from alkali. 
 
 TASSAJERO CLAY LOAM. Mapped in the Livermore area. Dark 
 brown, three feet. SUBSOIL: Same, lighter colored. OCCURS on 
 valley floor, well drained. ORIGIN: Colluvial and alluvial. CROPS: 
 Hay, grain, peaches, prunes, apricots. 
 
 VINA CLAY LOAM. Mapped in the Red Bluflf area. Brown; pud- 
 dles but is friable with tillage; two to six feet. SUBSOIL: Clay loam 
 or loam, or volcanic conglomerate. OCCURS in broad tracts, below 
 terraces, level, marked by abandoned water channels, overflowed, 
 drainage sluggish. ORIGIN: Alluvial. VEGETATION: Valley oaks, 
 wild oats. CROP: Grain, adapted to stone fruits. 
 WILLOWS CLAY LOAM. Mapped in the Colusa and Woodland 
 areas. Chocolate brown, yellow, three to six feet deep; drainage 
 poor. SUBSOIL: Reddish brown, heavy, compact clay loam. OC- 
 CURS: Occupies nearly flat depressions and low ridges of the valley 
 plain. ORIGIN: Wash from slopes; deposits from small foothill 
 streams. CROPS: Dry farming, pasture, alfalfa, grapes. When well 
 drained is well adapted to alfalfa, sugar beets, wine, table and raism 
 grapes, and general farm crops. Generally free from alkali. NATIVE 
 VEGETATION: Willows. 
 
 YOLO CLAY LOAM. Mapped in the Woodland area. Light to 
 chocolate brown; three feet deep, well drained. SUBSOIL: Heavy 
 clay loam. OCCURS: Flat to undulating along the side slopes of 
 stream courses. ORIGIN: Alluvial. CROPS: Barley, wheat, hay, 
 alfalfa, beets, garden truck, wine and raisin grapes. 
 
 GRAVELLY CLAY LOAM 
 PLEASANTON GRAVELLY CLAY LOAM. Mapped in the Liver- 
 more area. Dark brown, 15 to 30 inches. SUBSOIL: Yellowish red 
 to brown. OCCURS on rough ridges and in deep ravines. ORIGIN: 
 Residual. CROPS^ Grazing. PHYSICAL ANALYSIS: Fine gravel, 
 6.6; coarse and, 10.7; medium sand, 6.9; line sand, 14.4; very fine sand, 
 9.4; silt, 26.1; clay, 25.6. 
 
 SILTY CLAY LOAMS 
 
 Fine Coarse Medium Fine Very fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Elder 0.1 0.2 0.4 5.9 17.1 56.6 19.5 
 
 Gridley 0.0 0.3 0.3 2.6 7.7 64.1 24.9 
 
 Maywood 0.4 1.0 1.4 6.8 8.5 58.5 22.9 
 
 Sacramento 0.0 0.2 0.3 6.4 14.5 61.5 17.3 
 
 Santa Rita 0.5 1.4 1.4 4.0 5.7 60.3 26.4 
 
 Willows 0.0 0.2 0.1 0.9 10.1 60.9 27.0 
 
 Highest 0.5 1.4 1.4 6.8 17.1 64.1 27.0 
 
 Lowest 0.0 0.2 0.1 0.9 5.7 56.6 17.3 
 
 Average 0.1 0.5 0.6 4.4 10.6 60.3 23.0 
 
SiLTY Clay 121 
 
 Soils that contain over 50 per cent of silt and clay are called silty 
 clay loam, if they contain 20 to 30 per cent clay and over 50 per cent 
 silt. They contain more of the fine sands than the silty clays and are 
 therefore more friable, and not so liable to check and bake, and are 
 easily tilled. They are compact and somewhat sticky and heavy when 
 wet, and check some when dry; yet they rarely puddle and are friable 
 under cultivation. 
 
 ELDER SILTY CLAY LOAM. Mapped in the Red Blufif area. 
 Gray, rich in organic matter, 24 to 30 inches. SUBSOIL: Heavy loam. 
 OCCURS along creek bottoms. ORIGIN: Alluvial. CROPS: Grain, 
 alfalfa. 
 
 GRIDLEY SILTY CLAY LOAM. Mapped in the Marysville area. 
 Dark reddish brown, without drainage. SUBSOIL: Black, heavy, clay 
 loam, calcareous hardpan. OCCURS in irregular areas, lower than 
 surrounding soils. ORIGIN: Alluvial. CROPS: Grain, pasture; 
 adapted to alfalfa, grapes, etc., when drained. 
 
 MAYWOOD SILTY CLAY LOAM. Mapped in the Red Bluff area. 
 Smooth te.xture, very compact, cracks on drying, si.x feet. SUBSOIL: 
 Same, lighter texture. OCCURS on plains, poorly drained. ORIGIN: 
 Reworked alluvial. CROPS: Peaches, figs, pears, alfalfa. 
 SACRAMENTO SILTY CLAY LOAM. Mapped in the Colusa, Red 
 Blufif and Woodland areas. Dark gray to dark brown, micaceous, well 
 drained, six feet. SUBSOIL: Same to clayish. OCCURS in narrow 
 areas, level flood plains, lower draws, lower hill slopes, marked by 
 sloughs. ORIGIN: Alluvial. CROPS: Sugar beets, prunes, citrus, 
 sorghum, alfalfa, hops, fruit, truck. One of the most productive soils 
 of the Colusa area. 
 
 SANTA RITA SILTY CLAY LOAM. Mapped in the Livermore 
 area. Dark gray, two to three feet. SUBSOIL: Same, of lighter color 
 and texture. OCCURS on low flat land, marked by abandoned drain- 
 age channels. ORIGIN: Originally swampy, but now naturally 
 drained. CROPS: Grain, hay, alfalfa, truck. 
 
 WILLOWS SILTY CLAY LOAM. Mapped in the Colusa area. 
 Ashen gray, three to six feet. SUBSOIL: Brown, yellowish red, or 
 reddish brown clay loam. OCCURS in irregular bodies, on the lower 
 portions of the nearly level plains. ORIGIN: Alluvial. CROPS: 
 Grazing, dry farming; when drained, adapted to alfalfa, sugar beets. 
 Alkali in minor spots. 
 
 LOAM ADOBES 
 
 Fine Coarse Medium Pine Very fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Placentia 0.7 1.9 2.3 14.0 26.8 30.5 21.5 
 
 Sierra 6.0 13.4 7.0 15.1 10.2 25.4 21.1 
 
 Stockton 0.5 3.0 3.2 15.2 21.6 30.8 25.9 
 
 Average 2.4 6.1 4.1 14.7 19.5 28.9 22.8 
 
 The loam adobes contain less silt than the clay or sandy adobes, 
 and a higher percent of the coarser sands. They possess a better bal- 
 anced quantity of the various sands than any of the other adobes. 
 While they are sticky and plastic they respond readily to draining 
 
122 Soils of Califoenia 
 
 and high cultivation and become favorite soils for grapes, and locally 
 for walnuts, citrus, olives, grapes and general fruits. 
 PLACENTIA LOAM ADOBE. Mapped as Fullerton sandy^ abode 
 in the Los Angeles and Santa Ana areas. Locally called "Foothill 
 soil" at Santa Ana. Brown to dark brown, three feet deep. SUB- 
 SOIL: A lighter phase of the soil, yellowish gray indurated sand, 
 sandy loam, sand, gravel, shaly sandstone. OCCURS: Rolling hills, 
 sloping plains, foothills. CROPS: Walnuts, beans, grains, wheat, 
 barley, citrus at Whittier, olives at Mirada, a great grain soil in south- 
 ern California. Generally free from alkali. 
 
 SIERRA LOAM ADOBE. Mapped as Sierra loam in the Sacramento 
 area. Dark red, six inches to six feet deep. SUBSOIL: Residual red 
 adobe. OCCURS on gently rolling slopes to steep rugged hill, rock 
 outcrops, boulders. CROPS: Hay, grain, grapes and fruit. 
 STOCKTON LOAM ADOBE. Mapped in the Stockton area. Black, 
 thirty inches. SUBSOIL: Yellow, silty, clay loam. OCCURS: Level, 
 low positions. ORIGIN: Lacustrine, modified by stream sediments. 
 CROPS: Hay, grain, alfalfa, forage, grazing. Locally alkaline in 
 spots. 
 
 STONY LOAMS 
 Fine Coarse Medium Fine Very fine 
 gravel sand sand sand sand Silt Clay 
 
 Sierra 5.3 9.3 4.9 14.5 10.8 32.3 22.4 
 
 Tuscan 4.0 6.0 4.9 11.8 20.0 30.1 23.1 
 
 Average 4.6 7.6 4.9 13.1 15.4 31.2 22.7 
 
 SIERRA STONY LOAM. Mapped in the Sacramento area. Brown 
 to black, six to thirty inches. SUBSOIL: Volcanic gravels, muds and 
 breccia. OCCURS in irregular-shaped bodies, on summits of flat- 
 topped volcanic ridges and knobs, surface strewn with boulders. 
 ORIGIN: Residual, the decomposition of andesitic boulders and the 
 volcanic muds and breccias. VEGETATION: Gray leaf pine, shrubs. 
 CROPS: Grazing. 
 
 TUSCAN STONY LOAM. Mapped in the Red Bluff area. Gray, 
 very variable in texture, porous, leachy, 18 to 72 inches. SUBSOIL: 
 Cemented volcanic material. OCCURS on level to rolling barren 
 plains. ORIGIN: Residual from volcanic flows. CROPS: Sheep 
 range. 
 
 STONY CLAY LOAM 
 
 VALLECITOS STONY CLAY LOAM. Mapped in the Livermore 
 area. Red brown, 10 to 24 inches. SUBSOIL: Brown clay loam. 
 OCCURS on hills and steep slopes with rock outcrops. ORIGIN: 
 Residual from metamorphic rocks. VEGETATION: Field oak, live 
 oak, buckeye, shrubs. CROPS: Grazing. PHYSICAL ANALYSIS: 
 Fine gravel, 1.6; coarse sand, 5.6; medium sand, 4.5; fine sand, 8.5; 
 very fine sand, 17.6; silt, 39.4; clay, 22.5. 
 
 CLAY LOAM ADOBES 
 Fine Coarse Medium Fine Very fine 
 gravel sand sand sand sand Silt Clay 
 
 Alamo 1.3 8.1 4.5 9.6 14.2 41.9 20.2 
 
 Danville 0.0 0.6 1.3 6.7 27.6 36.9 27.2 
 
 Dublin 0.0 0.4 1.4 16.0 24.9 27.3 30.1 
 
Sixty Clay 123 
 
 Fine Coarse Medium Fine Very fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Oxnard 0.9 ,3.2 2.1 7.6 10.8 36.0 35.4 
 
 Pajaro 0.0 0.5 0.2 4.6 12.6 55.5 27.0 
 
 Placentia 2.8 3.1 7.1 24.5 31.1 19.6 8.8 
 
 Portersvllle 4.3 8.4 4.1 7.8 6.8 32.3 36.1 
 
 San Joaquin 1.4 3.1 1.3 4.9 9.5 44.8 35.1 
 
 Sites 0.0 3.6 5.0 16.3 12.5 36.8 25.7 
 
 Sutter 1.0 5.1 4.3 14.2 8.0 41.7 25.8 
 
 Stockton 0.6 1.9 3.0 8.3 14.5 42.6 27.9 
 
 Watsonville 0.2 0.8 0.9 12.3 16.9 46.6 22.1 
 
 Lowest 0.0 0.4 0.2 4.6 6.8 19.6 8.8 
 
 Highest 4.3 8.4 5.0 16.0 31.1 55.5 36.1 
 
 Average 1.0 3.2 2.8 9.4 13.2 38.5 21.8 
 
 The clay loam abodes are similar to the loam adobes except in the 
 larger percent of clay and silt. This makes them heavy and dense, 
 and causes them to absorb and hold large quantities of water. They 
 are hard to plow when dry and break up into clods. They are fairly 
 easy to cultivate if well drained and not too wet. When too wet they 
 become waxy and sticky and puddle, and bake and crack on drying. 
 They are rich in plant food and have a higher agricultural value than 
 the other adobes. These soils were formerly given up wholly to grain, 
 hay, and grazing, but their value is now appreciated and drainage and 
 proper handling is adding every year to their reputation for special 
 crops. 
 
 ALAMO CLAY LOAM ADOBE. Mapped in the Marysville area. 
 Dark reddish brown to red, 12 to 30 inches deep. SUBSOIL: Dense 
 hardpan. OCCURS in low positions, level, hog wallows, poorly 
 drained. ORIGIN: Alluvial wash. CROPS: Pasture, sown to hay, 
 adapted to Tokay grapes, etc. 
 
 DANVILLE CLAY LOAM ADOBE. Mapped in the Livermore 
 area. Brown to black, carries some shale and angular rock fragments, 
 24 to 36 inches. SUBSOIL: Clay loam. OCCURS on valley floor. 
 ORIGIN: Colluvial and alluvial. CROPS: Dry farmed to grain, 
 deciduous fruits do well under irrigation. 
 
 DUBLIN CLAY LOAM ADOBE. Mapped in the Livermore area. 
 Brown to black, carries shale fragments, 18 to 48 inches. SUBSOIL: 
 Yellow clay loam. OCCURS on valley bottom and sides. ORIGIN: 
 Colluvial and alluvial. CROPS: Dry farmed to hay and grain. 
 OXNARD CLAY LOAM ADOBE. Mapped as San Joaquin black 
 adobe in the Los Angeles, Lower Salinas Valley, San Bernardino, San 
 Gabriel, Santa Ana and Ventura areas. Black to dark brown, three 
 to six feet, usually well drained. SUBSOIL: Shale, shaly sand- 
 stone, sandy loam, sand, gravel. OCCURS along river beds, capping 
 shaly hills, on level valley floors, low rolling hills, slough and lake 
 bottoms. ORIGIN: Weathering of argillaceous sandstones and shale 
 in place, or the washings from them. CROPS: Grain, alfalfa, corn, 
 barley. Generally free from alkali. 
 
 PAJARO CLAY LOAM ADOBE. Mapped in the Pajaro area. 
 Black, high percent of lime and humus, poorly drained, apt to be 
 water-logged, naturally very fertile, three feet deep. SUBSOIL: Com- 
 pact clay loam, or siity clay loam. OCCURS on low elevations along 
 rivers. ORIGIN: Composed of weathered shale, the finer or clay 
 
124 Soils of California 
 
 particles of which were deposited in quiet waters. CROPS: Apples, 
 alfalfa, strawberries, loganberries, raspberries, blackberries, sugar 
 beets, beans, onions, barley. 
 
 PLACENTIA CLAY LOAM ADOBE. Mapped as Sierra adobe in 
 the Fresno area. Reddish. SUBSOIL: Same. OCCURS: Foothills, 
 steep land. ORIGIN: Normal product of the weathering of the gran- 
 itic rocks of the foothills. CROPS: Dry farming. 
 PORTERSVILLE CLAY LOAM ADOBE. Mapped in the Porters- 
 ville area. Dark brown, two to six feet deep, carries subangular frag- 
 ments. SUBSOIL: Reddish brown to almost white, marly. OCCURS: 
 Locally called "Dry bog adobe," found on the outer slopes of the foot- 
 hills of the Coast Range, quite steep. ORIGIN: Residual, from 
 weathering and decomposition of the underlying granitic rocks, which 
 are associated with magnesite and lime. CROPS: Formerly to grain, 
 especially adapted to oranges and lemons. Free from alkali. 
 SAN JOAQUIN CLAY LOAM ADOBE. Mapped as San Joaquin 
 red adobe in the Sacramento area. Red, two to three feet. SUB- 
 SOIL: Red sandy hardpan. OCCURS: Lower slopes of the valley 
 plains, smooth. ORIGIN: Alluvial. CROPS: Grain and hay. 
 SITES CLAY LOAM ADOBE. Mapped in the Colusa and Wood- 
 land areas. Reddish to gray browns, six feet deep, gravelly. SUB- 
 SOIL: Silt, red clay, clay loam adobe, red clay hardpan, gravelly loam, 
 cemented gravel. OCCURS on lower undulating foothills of the 
 Coast Range. ORIGIN: Weathering from sandstone, shale and con- 
 glomerate. CROPS: Dry farmed, grazing, grain. 
 
 SUTTER CLAY LOAM ADOBE. Mapped in the Marysville area. 
 Chocolate brown, two to three inches. SUBSOIL: Same, lighter 
 brown. OCCURS in irregular-shaped small bodies in the smaller val- 
 leys. ORIGIN: Wash from the volcanic rocks of the Marysville 
 Buttes, and from adjacent soils. CROPS: Grain cut for hay. 
 STOCKTON CLAY LOAM ADOBE. Mapped in the Stockton area. 
 Mapped as San Joaquin black adobe in the San Jose, Hanford and 
 Fresno areas. Locally called "Dry bog soil." Black, three to six feet 
 deep, poorly drained. SUBSOIL: Yellow, heavy silty or silty clay 
 hardpan. OCCURS on low level flat plains, lower levels or depres- 
 sions of valley floor. ORIGIN: Old lacustrine or swamp deposits 
 modified. CROPS: Alfalfa, wheat, rye, barley, forage grass, veget- 
 ables, flower seeds, strawberries, raspberries, sugar beets, apples, 
 I)ears orunes at San Jose and Santa Clara. Generally free from alkali. 
 WATSONVILLE CLAY LOAM ADOBE. Mapped in the Pajaro 
 area. Black to dark brown, 20 to 30 inches deep. SUBSOIL: Yellow, 
 gritty clay loam. OCCURS: Lowest hills and their slopes adjacent 
 to the river. ORIGIN: Residual from decomposing shales. CROPS: 
 Grains, pears, eucalyptus. 
 
CHAPTER XVII 
 
 SILT LOAMS. LOAMS. 
 
 Fine Coarse Medium Fine Very fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Feather 0.0 0.2 0.2 0.7 4.2 81.1 13.4 
 
 Gila 0.5 0.3 0.3 2.7 10.3 54.8 31.3 
 
 Hanford 0.2 0.8 0.7 5.5 13.3 58.0 19.5 
 
 Marysville 0.0 0.8 0.5 5.2 13.7 57.1 22.6 
 
 Maywood 1.6 2.2 1.9 9.5 11.3 57.3 15.9 
 
 Oxnard 0.0 0.5 0.7 8.1 10.5 55.9 19.9 
 
 Pajaro 0.0 0.1 0.1 10.6 22.2 53.3 12.7 
 
 Sacramento 0.0 0.6 1.0 8.8 9.6 64.1 16.0 
 
 Sites 0.5 3.1 3.2 6.0 8.6 60.5 18.1 
 
 Stockton 1.0 6.6 6.0 16.7 15.3 53.5 18.8 
 
 Yolo 0.0 0.1 0.1 1.2 5.0 69.1 24.4 
 
 Highest 1.6 6.6 6.0 16.7 22.2 81.1 24.4 
 
 Lowest 0.0 0.1 0.1 0.7 4.2 53.3 12.7 
 
 Average 0.3 1.4 1.3 6.8 11.2 60.4 19.3 
 
 When soils contain over 50 per cent of silt and clay they are 
 called silt loams, if they contain less than 20 per cent clay or over SO 
 per cent silt. They are finer than the fine sandy loams, and the par- 
 ticles are very uniform in size. They are fine, close, and dense in tex- 
 ture, retentive of moisture; very sticky and liable to puddle if plowed 
 when wet, but loose and friable when dry. If plowed when too dry, 
 they form large hard clods. Under cultivation they break into a fine 
 friable loam. They are generally rich in organic matter. 
 ELDER SILT LOAM. Mapped in the Red Bluflf area. Gray, smooth, 
 friable, six feet. SUBSOIL: Coarse alluvium. OCCURS as broad 
 alluvial bottoms, well drained. ORIGIN: Alluvial. CROPS: Dry 
 farmed to grains, adapted to prunes, peaches, wheat, barley, alfalfa, 
 sugar beets, melons, truck. 
 
 FEATHER SILT LOAM. Mapped in the Marysville area. Light to 
 dark brown, shale particles, six feet. SUBSOIL: Similar but heavier. 
 OCCURS in river bottoms. ORIGIN: Alluvial deposited by creeks, 
 subject to annual overflow. Locally called "Black Land." CROPS: 
 Alfalfa, corn, sorghum; adapted to truck crops and small fruits. 
 GILA SILT LOAM. Mapped as Imperial silt loam in the Yuma- 
 California area. Mapped as Santiago silt loam, Yuma area. Gray to 
 brown, poorly drained, 12 to 30 inches. SUBSOIL: Sand, loam, clays. 
 OCCURS on lands overflowed by annual river floods, in low places, 
 comparatively level, in long strips. ORIGIN: Sediments deposited 
 after the river floods have been robbed of their fine sand. CROPS: 
 Kaffir, Egyptian and Indian corn, Milo maize, millet, sorghum, garden 
 vegetables, melons, pumpkins. Often free from alkali. 
 HANFORD SILT LOAM. Mapped in the Modesto-Turlock area. 
 Mapped as Santiago silt loam in the Los Angeles, Lower Salinas Val- 
 ley areas. Mapped as Sacramento silt loam in the Sacramento area, 
 
126 Soils of California 
 
 and mapped as Fresno fine sandy loam in the San Jose area. Brown 
 to black, yellowish to gray, micaceous, very sticky, two to six feet, wet 
 and poorly drained in places; light colored are friable and the dark 
 colored are heavy. SUBSOIL: Sand, silt, brown or dark clay loam, 
 lighter sediments. OCCURS in long narrow strips in irregular-shaped 
 bodies, on flat plains, river terraces, in slight depressions, level, locally 
 subject to overflow. ORIGIN: Alluvial, deposited along stream flood 
 plains and in depression by slack silt-laden waters. CROPS: Alfalfa, 
 strawberries, raspberries, beans, potatoes, sugar beets, hops, asparagus. 
 Generally small amounts of alkali near the surface, heavy locally. 
 
 MARYSVILLE SILT LOAM. Mapped in the Marysville area. 
 Light brown, poorly drained, overflowed, 18 inches to 4 feet. SUB- 
 SOIL: Reddish brown sticky silty clay loam, gray hardpan. OCCURS 
 at junction of streams subject to floods. ORIGIN: Alluvial. CROPS: 
 Where drainage is possible, alfalfa, grapes, stone fruits. 
 MAYWOOD SILT LOAM. Mapped in the Red BlufJ area. Yellow- 
 ish gray, smooth texture, compact, sticky when wet, friable when 
 properly handled, uniform, 30 to 36 inches. SUBSOIL: Silty chiy 
 loam. OCCURS along minor streams. Drainage adequate. ORIGIN: 
 Alluvial. VEGETATION: Oaks, willows. CROPS: Dry farming, 
 orchards. 
 
 OXNARD SILT LOAM. Mapped in the San Jose and Ventura areas. 
 That mapped as Oxnard silt loam in the Bakersfield area has been 
 reclassified as Hanford clay loam. Brownish, well drained; heavier 
 phases resemble true adobe. OCCURS in bodies of irregular outline, 
 between valley bottoms and base of mountains, slightly undulating, 
 level, smooth plains. ORIGIN: Deposition of finer particles held in 
 suspension by flood waters, disintegrated sandstone mixed with 
 organic matter. CROPS: Very fertile — prunes, apricots, cherries, 
 apples, small fruits, hay, lima beans, walnuts, citrus fruits. Some 
 alkali where drainage is deficient. 
 
 PAJARO SILT LOAM. Mapped in the Pajaro area. Brown, smooth, 
 micaceous, three feet. SUBSOIL: Lighter in texture and color, 30 
 feet. OCCURS parallel to the rivers, scalloped by river floods. 
 ORIGIN: From weathered and transported shales. CROPS: Very 
 fertile; apples, alfalfa, sugar beets, beans, potatoes, strawberries, 
 loganberries, blackberries, raspberries. PHASE: Light silt loam, 
 mapped in the Pajaro area, light brown, very micaceous, six feet, sim- 
 ilar subsoil. OCCURS: Low lying, occasionally flooded. CROPS: 
 Apples, berries, truck gardening. 
 
 SACRAMENTO SILT LOAM. Mapped in the Colusa, Marysville, 
 Modesto-Turlock, Woodland, Red Bluff and Redding areas. That 
 mapped as Sacramento silt loam in the Sacramento area has been 
 reclassified as Hanford silt loam. Light to yellowish brown, dark 
 brown, drab, gray, micaceous, often gravelly, well drained, 18 inches 
 to 20 feet. SUBSOIL: Same, deeper color, compact, sand, gravel. 
 OCCURS: Stream bottoms, in narrow bodies, level. ORIGIN: Allu- 
 vial deposited by stream floods. CROPS: Wheat, barley, grapes, 
 alfalfa, hops, broom corn, sugar beets, truck, peaches, prunes, pears. 
 Free from excess of alkali. 
 
Silt Loams Loams 
 
 127 
 
 SITES SILT LOAM. Mapped in the Woodland area. Yellow to red 
 brown, smooth texture, some water-worn gravel, two feet. SUB- 
 SOIL: Dark red loam, clay loam, sandy loam. OCCURS as broad 
 slopes near base of hills. ORIGIN: Residual and colluvial. CROPS: 
 Barley, wheat, with proper cultivation adapted to grapes, almonds, 
 apricots. 
 
 STOCKTON SILT LOAM. Mapped in the Stockton area. Light 
 brown, well drained, six feet. SUBSOIL: Lighter colored, more com- 
 pact, hardpan. OCCURS in large irregular-shaped level bodies. 
 ORIGIN: From a large variety of rocks. CROPS: Vegetables, wheat, 
 barley, oats, alfalfa, root crops, almonds, cherries, peaches, late grapes. 
 Free from alkali. 
 
 TEHAMA SILT LOAM. Mapped in the Red Bluflf area. Yellow 
 brown to red yellow, puddles, 10 to 20 inches. SUBSOIL: Brown 
 silty clay loam. OCCURS on intermediate plains of gentle slope, 
 poorly drained. ORIGIN: Recent alluvial from Red Bluff formation. 
 CROP: Dry farmed to grain; under irrigation adapted to berry, 
 alfalfa, grapes, farm crops. 
 
 VINA SILT LOAM. Mapped in the Red Bluff area. Brown, six 
 feet. SUBSOIL: Volcanic gravel. OCCURS bordering stream chan- 
 nels. ORIGIN: Alluvial. VEGETATION: Oak, cottonwood, wil- 
 lows, sycamore, wild oats. CROPS: Alfalfa, grain, peaches, prunes, 
 grapes, sugar beets, truck. 
 
 YOLO SILT LOAM. Mapped in the Woodland area. Light to dark 
 brown, heavy, three feet, good drainage. SUBSOIL: Brown silty 
 clay, loose sandy loam. OCCURS in large irregular-shaped bodies, 
 along sides of creeks, on slopes approaching the ridges along stream 
 channels. CROPS: Dry farmed to grain, well adapted to a wide 
 range of crops if irrigated; alfalfa, sugar beets, garden vegetables, etc. 
 
 
 
 
 LOAMS 
 
 
 
 
 
 
 Fine 
 
 Coarse 
 
 Medium 
 
 Fine 
 
 Very fine 
 
 
 
 
 gravel 
 
 sand 
 
 sand 
 
 sand 
 
 sand 
 
 Silt 
 
 Clay 
 
 Arbuckle . . . 
 
 .. . 0.0 
 
 0.7 
 
 1.2 
 
 6.2 
 
 23.1 
 
 45.6 
 
 23.1 
 
 Arnold 
 
 ... 2.9 
 
 12.1 
 
 6.7 
 
 16.9 
 
 7.3 
 
 44.2 
 
 10.4 
 
 Bear 
 
 ... 0.2 
 
 1.7 
 3.0 
 
 1.8 
 5.4 
 
 7.6 
 22.1 
 
 17.0 
 5.4 
 
 49.2 
 45.2 
 
 22.4 
 
 Corralitos . . . 
 
 ... 0.1 
 
 18.7 
 
 Dublin 
 
 .. . 0.6 
 
 2.4 
 
 3.9 
 
 18.4 
 
 31.7 
 
 25.3 
 
 17.5 
 
 Esparto .... 
 
 ... 0.2 
 
 1.5 
 
 3.1 
 
 18.9 
 
 21.4 
 
 32.6 
 
 22.2 
 
 Feather. . . . 
 
 ... 0.0 
 
 0.9 
 
 1.1 
 
 11.2 
 
 25.8 
 
 45.2 
 
 15.9 
 
 Fresno 
 
 ... 0.4 
 
 3.6 
 
 3.0 
 
 11.2 
 
 18.8 
 
 40.7 
 
 22.1 
 
 Gila 
 
 ... 0.0 
 
 0.3 
 4.4 
 6.1 
 
 1.5 
 3.3 
 6.7 
 
 15.2 
 13.6 
 17.4 
 
 29.4 
 
 17.1 
 
 9.6 
 
 43.8 
 40.6 
 39.8 
 
 9.5 
 
 Gridley 
 
 ... 0.2 
 
 20.7 
 
 Hanford .... 
 
 ... 1.7 
 
 18.8 
 
 Honicut .... 
 
 ... 0.6 
 
 3.9 
 
 2.9 
 
 13.4 
 
 14.0 
 
 46.8 
 
 18.5 
 
 Llvermore . . 
 
 ... 0.3 
 
 1.2 
 
 2.5 
 
 15.7 
 
 29.9 
 
 32.1 
 
 18.2 
 
 Maywood . . . 
 
 ... 1.2 
 
 2.4 
 
 2.8 
 
 13.1 
 
 19.3 
 
 47.2 
 
 13.5 
 
 Mocho 
 
 ... 2.6 
 
 4.0 
 
 8.8 
 
 6.4 
 
 6.5 
 
 20.0 
 18.4 
 
 17.7 
 9.9 
 
 34.9 
 37.9 
 
 14.4 
 
 Modesto .... 
 
 ... 1.9 
 
 16.1 
 
 Oxnard 
 
 ... 0.8 
 
 3.4 
 
 3.9 
 
 23.0 
 
 7.4 
 
 42.3 
 
 15.4 
 
 
 ... 0.0 
 
 0.4 
 4.0 
 
 0.4 
 4.8 
 
 7.6 
 19.6 
 
 19.5 
 10.9 
 
 54.8 
 39.6 
 
 16.4 
 
 Placentia . . . 
 
 ... 1.8 
 
 16.8 
 
 Pleasanton . 
 
 ... 2.9 
 
 3.9 
 
 3.7 
 
 10.2 
 
 19.2 
 
 44.1 
 
 15.8 
 
 Portersville . . 
 
 ... 4.0 
 
 11.2 
 
 9.0 
 
 23.9 
 
 8.6 
 
 22.5 
 
 20.8 
 
 Redding .... 
 
 . . . "4.4 
 
 11.4 
 
 5.5 
 
 13.1 
 
 14.4 
 
 34.8 
 
 16.6 
 
 Sacramento . 
 
 ... 0.9 
 
 2.7 
 
 3.0 
 
 14.9 
 
 18.0 
 
 45.3 
 
 14.4 
 
128 
 
 Soils of California 
 
 Fine Coarse Medium Fine Very fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Salsipuedes 1.7 6.4 4.9 19.4 10.8 41.0 16.1 
 
 San Joaquin .... 1.8 8.2 5.6 13.5 13.3 40.7 16.5 
 
 Santiago 0.0 2.5 1.6 8.8 24.7 43.0 15.9 
 
 Santa Cruz 1.1 8.6 8.6 30.1 5.2 23.9 22.0 
 
 Santa Rita 0.1 0.6 1.3 6.4 32.2 41.3 17.9 
 
 Sierra 3.3 10.6 5.9 11.9 8.9 45.1 14.3 
 
 Sites 1.6 3.4 3.1 17 6 20.1 39.1 14.8 
 
 Stockton 0.3 6.8 6.0 25.3 15.6 26.5 18.9 
 
 Sunol 0.2 0.9 1.7 10.9 15.4 48.3 22.4 
 
 Sutter 1.5 5.2 5.4 13.5 11.8 37.9 24.8 
 
 Ulmar 0.8 3.0 4.4 13.2 20.8 37.1 20.3 
 
 Vallecitos 0.2 2.3 5.9 20.8 28.7 22.7 19.2 
 
 Vina 1.4 2.8 3.6 12.5 19.1 45.8 14.8 
 
 Watsonville 1.3 6.5 9.3 22.3 11.7 26.9 22.0 
 
 Willows 0.9 2.6 2.6 10.6 12.1 44.8 25.9 
 
 Yolo 0.1 0.4 0.9 9.5 27.3 43.5 18.2 
 
 Highest 4.4 12.1 9.3 30.1 32.2 54.8 25.9 
 
 Lowest 0.0 0.3 0.4 6.2 5.2 22.5 9.5 
 
 Average 0.2 3.9 4.4 17.3 16.7 39.7 17.9 
 
 If soils contain over 50 per cent of silt and clay they are called 
 loam, if they contain less than 20 per cent of clay and less than 50 
 per cent of silt. They are the most useful all-around soils, combining 
 the lightness and earliness of the sands, with the strength and reten- 
 tiveness of the clays. They are smooth, uniform, open, porous, and 
 have high capillary power. While naturally compact and liable to be 
 sticky or even puddle when wet, they are loose and powdery when dry 
 and easily cultivated where well drained, and maintain an excellent 
 tilth. They work easily and do not crack or crust. Water moves 
 easily in them and to long distances. 
 
 ARBUCKLE LOAM, Mapped in the Woodland area. Light to gray 
 brown. SUBSOII^: Variable in texture, brown sandy loam. loam. 
 OCCURS near present or former streams, sloping, slightly uneven, 
 well drained. ORIGIN: Lacustrine, alluvial. CROPS: Wheat, al- 
 monds, raisins, fine grape soil, adapted to alfalfa, fruit, Kaffir and 
 Egyptian corn, sorghum, beets and general farm crops. 
 ARNOLD LOAM. Mapped in the Modesto-Turlock area. Grayish 
 brown, red, black, mottled, light, sandy, ten to fifteen inches. SUB- 
 SOIL: Heavy loam. OCCURS: Covering undulating hills. ORIGIN: 
 Lacustrine, alluvial. CROPS: Dry farming to grain. 
 BEAR LOAM. Mapped in the Marvsville area. Reddish brown, well 
 drained, four to six feet deep. OCCURS: Bottom lands. ORIGIN: 
 Material washed from adjaceint plains soils. CROPS: Grain, hay. 
 alfalfa, stone fruits, grapes, hops. 
 
 CORNING LOAM. Mapped in the Red Bluff area. Reddish, slightly 
 sticky, with tendency to clog and puddle, sixteen to thirty inches. 
 SUBSOIL: Clay or clav loam. OCCURS on upland plains, level to 
 gentlv rolling. ORIGIN: Alluvium from Red Bluff formation. 
 CROPS: Dry farmed to grain. When irrigated it is adapted to 
 peaches, almonds, iigs, berries, grapes, etc. 
 
 CORRALITOS LOAM. Mapped in the Pajaro area. Chocolate 
 brown, micaceous, three feet deep. SUBSOIL: Brown to yellowish 
 brown micaceous loam, thirty feet deep. OCCURS: Oval-shaped body 
 on higher plain. ORIGIN: Washings from rotten shales from adja- 
 
Silt Loams Loams 129 
 
 cent hills, mixed with creek alluvium. CROPS: Generally devoted to 
 grazing, dry farming to grain, apples, apricots, prunes, English wal- 
 nuts, vegetables, berries, etc. 
 
 DUBLIN LOAM. Mapped in the Livermore area. Dark brown to 
 black, two to three feet. SUBSOIL: Gray brown silt loam. OCCURS 
 along creek bottoms. ORIGIN: Colluvial. VEGETATION: Oak, 
 willow, sycamore. CROPS: Dry farmed to hay and grain, adapted 
 under irrigation to fruit, truck, alfalfa. 
 
 ESPARTO LOAM. Mapped in the Woodland area. Brown to yel- 
 lowish brown, well drained, 24 inches. SUBSOIL: Brown clay loam. 
 OCCURS: Moderate elevations near sloughs. ORIGIN: Recent allu- 
 vial. CROPS: Excellent grape soil, apricots, almonds, plums, olives, 
 figs, alfalfa. Free from alkali. 
 
 FEATHER LOAM. Mapped in the Marysville area. Reddish brown, 
 poorly drained, named for the Feather River; six feet. SUBSOIL: 
 Heavier. OCCURS along river bottoms, flooded. ORIGIN: Alluvial 
 and sedimentary, and subject to alterations by floods. CROPS: Where 
 reclaimed, excellent for alfalfa, peaches, pears. 
 
 FRESNO LOAM, Mapped in the Modesto-Turlock and Porters- 
 ville areas. Mapped as Maricopa loam in the Fresno area. Chocolate 
 to gray brown, red, micaceous, one to six feet. SUBSOIL: Mica- 
 ceous fine sand, fine sandy loam. OCCURS in low flat tracts, uneven 
 surface, offer hummocky. ORIGIN: from very fine sediments laid 
 down at former periods by slack water from old river channels, lacus- 
 trine. CROPS: Often uncultivated owing to lack of water, dry 
 farming to grain, grazing; adapted to alfalfa, corn, grain, etc., where 
 irrigated. Impregnated in places with soluble alkali salts and common 
 salt. 
 
 GILA LOAM. Mapped as Imperial fine sandy loam in the Yuma- 
 California area. Three to twenty feet deep. SUBSOIL: Coarser sand, 
 fine sandy loam. OCCURS in long narrow strips along the Colorado 
 River, smooth, often covered with cottonwood, willow or arrow-weed. 
 ORIGIN: Sediments deposited by river in the annual floods. CROPS: 
 All shallow rooted vines, fruits, vegetables. Sometimes heavy in 
 alkali, but can generally be reclaimed by one year's heavy flooding. 
 GRIDLEY LOAM. Mapped in the Marysville area. A reddish 
 brown, light, little natural surface drainage, two to six feet. SUB- 
 SOIL: Black, clay loam, adobe-like, gray calcareous hardpan. 
 OCCURS: Extensive level plain, surface slightly uneven, contains 
 depressions with no outlet. ORIGIN: Sedimentary altered by river 
 floods. CROPS: Requires drainage ditches; alfalfa, fruits, peaches, 
 pears, apricots, apples, grapes, almonds, figs. 
 
 HANFORD LOAM. Mapped in the Portersville area. Dark gray, 
 28 to 60 inches. SUBSOIL: heavy yellowish or reddish brown loam, 
 light clay loam. OCCURS: Level, no local drainage. ORIGIN: 
 Alluvial material deposited in quiet water. CROPS: Grazing, alfalfa. 
 HONICUT LOAM. Mapped in the Marysville area. Reddish brown, 
 two feet. SUBSOIL: Dark red loam. OCCURS: Level, well drained. 
 ORIGIN: Alluvial washed from higher soils. CROPS: Truck, alfalfa, 
 berries, figs, stone fruits. 
 
130 Soils of California 
 
 LIVERMORE LOAM, Mapped in the Livermore area. Dark brown, 
 thirty to thirty-six inches. SUBSOIL: Light brown silty loam. 
 OCCURS as strips and irregular bodies on valley floor, level, marked 
 by abandoned stream channels, well drained. ORIGIN: Colluvial 
 and alluvial. CROP: Hay, barley, wheat, grapes, almonds. 
 MAYWOOD LOAM. Mapped in the Red Bluflf area. Grayish or 
 yellowish gray, two to six feet. SUBSOIL: Yellow clay loam. OC- 
 CURS on gently rolling valley plains. ORIGIN: Reworked alluvial 
 material. CROP: Dry farmed to grain, adapted to almonds, 
 olives, etc. 
 
 MOCHO LOAM. Mapped in the Livermore area. Dark brown to 
 drab, eighteen to twenty-four inches. SUBSOIL: Gray brown sands. 
 OCCURS on level land along creeks. ORIGIN: Alluvial wash from 
 adjacent soils. CROPS: Hay, grain, truck, fruit. 
 MODESTO LOAM. Mapped in the Modesto-Turlock area. Choco- 
 alte brown, gray, coarse granite sand, twelve inches. SUBSOIL: 
 Clay loam, sandy loam. OCCURS: Uneven, level stretches with hog- 
 wallow depressions, hummocks. ORIGIN: From old overflowed chan- 
 nel deposits. CROPS: Alfalfa, grapes, peaches where drained. Ele- 
 vated portions free from alkali. 
 
 OXNARD LOAM. Mapped in the San Bernardino area. Mapped as 
 Fresno line sandy loam in the Ventura area. That mapped as Oxnard 
 loam in the San Jose and Ventura areas has been reclassified as Ox- 
 nard clay loam. Gray, sticky, micaceous, drainage good, three to six 
 feet deep. SUBSOIL: Dark adobe. OCCURS: Level, smooth, gently 
 sloping plains, hillsides, skirting gullies. ORIGIN: Derived from 
 shale and shaly sandstone, unconsolidated sandstones. CROPS: Pas- 
 ture, wheat, alfalfa, lima beans, English walnuts, citrus fruits. Free 
 from alkali, where well drained. 
 
 PAJARO LOAM. Mapped in the Pajaro area. Dark brown or black, 
 heavy, micaceous, high percent of humus, generous lime content, 
 twelve to eighteen inches. SUBSOIL: Light yellow silt loam, thirty 
 feet deep. OCCURS: Along the lower lands of the rivers and creeks. 
 ORIGIN: Alluvial and sedimentary. CROPS: Apples, alfalfa, sugar 
 beets, beans, potatoes, onions, strawberries, blackberries, loganberries. 
 PLACENTIA LOAM. Mapped as Placentia sandy loam in the Ven- 
 tura area. Mapped as Los Angeles sandy loam in the Los Angeles 
 area. That mapped as Placentia loam in the San Bernardino area has 
 been reclassified as Placentia clay loam. Reddish brown to light 
 brown, two to six feet deep. SUBSOIL: Hardpan, decayed rock, yel- 
 lowish to gray. OCCURS on low rolling hills, steep grades, rough 
 hills. ORIGIN: Disintegration of sandstones and shale in place, 
 wash from sandstone. CROPS: Barley, corn, blackeyed beans, apri- 
 cots, oranges. Generally free from alkali. 
 
 PLEASANTON LOAM. Mapped in the Pleasanton area. Brown, 
 high percent of gravel, sticky, forms surface crust on drying that yields 
 readily to tillage, twelve to thirty inches. SUBSOIL: Reddish clay 
 loam. OCCURS on the lower slopes of the hills. ORIGIN: Sedi- 
 mentary. VEGETATION: Oaks. CROPS: Wine grapes, adapted to 
 fruit, alfalfa, truck. 
 
Silt Loams Loams 131 
 
 PORTERSVILLE LOAM. Mapped in the Portersville area. Gray- 
 ish red, micaceous, eighteen inches to six feet deep. SUBSOIL: 
 Granitic rock. OCCURS: Granitic foothills and mesas. ORIGIN: 
 Residual, from the underlying granitic rocks, more or less modified 
 by rain wash and alluvial action. CROPS: Dry farming to grain, 
 pasture, citrus fruits. Free from alkali. 
 
 REDDING LOAM. Mapped in the Redding area. Light red to red- 
 dish gray, eight to twelve inches. SUBSOIL: Dark red, heavy, clay 
 loam, sandy clay hardpan. OCCURS: Upland plains. CROPS: Graz- 
 ing, wheat, small fruits, table and wine grapes where locally deep. 
 SACRAMENTO LOAM. Mapped in the Colusa and Redding areas. 
 Light to dark brown, dark gray, drab, three to six feet. SUBSOIL: 
 Sands, gravel. OCCURS in irregular bodies, long narrow areas, level 
 and gently sloping, valley plains, stream bottoms. ORIGIN: Recent, 
 alluvial. CROPS: Alfalfa, beets, grazing, dry farming to grain. 
 
 SALSIPUEDES LOAM. Mapped in the Pajaro area. Dark brown, 
 gritty, three feet deep. SUBSOIL: Brown loam, sandy loam. OC- 
 CURS: Slope of foothills, valley. ORIGIN: CoUuvial from shale, 
 and wash from adjacent hills. CROPS: Apple, prune, apricot. 
 
 SAN JOAQUIN LOAM. Mapped in the Colusa, Modesto-Turlock, 
 Marysville, and Stockton areas. Reddish to yellowish gray, dark red, 
 texture variable, often gravelly, ten inches to three feet. SUBSOIL: 
 Brown to reddish brown, heavy clay loam, yellow to red hardpan. 
 OCCURS on gentle slopes, valley plains, foothills, rolling uplands. 
 ORIGIN: Modified early Pleistocene deposits. CROPS: Grain, with 
 irrigation, alfalfa, fruit, Tokay grapes, general farm crops. 
 SANTIAGO LOAM. Mapped in the Santa Ana area, three to six 
 feet. SUBSOIL: Sand, gravel. OCCURS: Level to rough and 
 broken. CROPS: Wheat, barley. 
 
 SANTA CRUZ LOAM. Mapped in the Pajaro area. Brown, filled 
 with lenticular shale fragments, gritty, thirty inches. SUBSOIL: Yel- 
 low or drab silt loam. OCCURS: Higher ridges and slopes along 
 creeks and ravines. ORIGIN: From weathering of shale in place. 
 CROPS: Apples, apricots. 
 
 SANTA RITA LOAM. Mapped in the Livermore area. Dark gray 
 to black, three feet. SUBSOIL: Gray silt loam. OCCURS on level 
 land. Drainage good. ORIGIN: Alluvial formed under swamp con- 
 ditions. CROPS: Hops, sugar beets, alfalfa. 
 
 SIERRA LOAM. Mapped in the Marysville area. That mapped as 
 Sierra loam in the Sacramento area is Sierra loam adobe. Red, con- 
 tains sharp angular rock fragments from the lone formation. SUB- 
 SOIL: Light brown to gray loam. OCCURS: Slopes of the lower 
 foothills of the Sierras. ORIGIN: Mainly residual, but along stream 
 courses partially colluvial, from the weathering of the underlying 
 andesite, amphibolitic rocks, and diabase; and from the lone forma- 
 tion. CROPS: Citrus fruits and olives where irrigated. 
 SITES LOAM. Mapped in the Colusa and Woodland areas. Light 
 gray, reddish brown, heavy, well drained, fourteen inches to four feet. 
 SUBSOIL: Light colored argillaceous sandstones, mixed with some 
 
132 Soils of California 
 
 shale, limestone, loams, etc. OCCURS in small irregular patches on 
 summits and slopes of lower foothills. ORIGIN: Colluvial, residual 
 from subsoil materials. CROPS: Grain and grazing, adapted to wide 
 range of crops. 
 
 STOCKTON LOAM. Mapped in the Stockton and Modesto-Turlock 
 areas. Chocolate brown to black, micaceous, one to six feet. SUB- 
 SOIL: Fine silty or sandy loam. OCCURS in irregular bodies, elong- 
 ated bodies along streams, foot of terraces, generally level. ORIGIN: 
 Alluvial, resulting from the deposition of heterogenous sediments in 
 ancient lakes or bays and streams, modified by admixture of more 
 recent sediments laid down by existing streams. CROPS: Alfalfa, 
 onions, cabbage, grains, hay, peaches, prunes, walnuts, grapes, garden 
 truck. Generally free from alkali. 
 
 SUNOL LOAM. Mapped in the Livermore area. Brown, carries 
 angular rock fragments, twenty-four to thirty-six inches. SUBSOIL: 
 Clay loam. OCCURS as level floor of valley. ORIGIN: Colluvial. 
 CROPS: Hay, grain, fruit and alfalfa under irrigation. 
 SUTTER LOAM. Mapped in the Marysville area. Grayish, some 
 tine gravel, eighteen inches to six feet. OCCURS: Irregular or sloping 
 lands, below edge of Buttes, in small valleys, sometimes subject to 
 overflow, sometimes a slight hog-wallow surface. ORIGIN: Largely 
 colluvial washed from adjacent buttes and altered by alluvial deposits. 
 CROPS: Pasturage, alfalfa, almonds. 
 
 ULMAR LOAM. Mapped in the Livermore area. Brown, fifteen 
 to twenty-four inches. SUBSOIL: Yellow or brown clay, and cal- 
 careous hardpan. OCCURS: Level, marked by hog-wallows. ORIGIN: 
 Colluvial and alluvial. CROPS: Hay, grain, grazing, under irrigation 
 adapted to strawberries, alfalfa, truck. 
 
 VALLECITOS LOAM. Mapped in the Livermore area. Reddish 
 brown, fifteen to thirty inches. SUBSOIL: Yellow clay loam. 
 OCCURS on rough hills and in deep ravines. ORIGIN: Residual 
 from metamorphic rocks. VEGETATION: Live oak, field oak, buck- 
 eye. CROPS: Hay, grain, grazing. 
 
 VINA LOAM. Mapped in the Red Bluff area. Locally called "Park 
 Soil." Red brown, two to six feet. SUBSOIL: Gravel. OCCURS 
 on fan-shaped stream deltas, gently sloping, often abrupt terraces. 
 ORIGIN: Part of a dissected plain. VEGETATION: Blue oak, cea- 
 nothus, chaparral. CROPS: Grain, berries, melons, peaches. 
 
 WATSONVILLE LOAM. Mapped in the Pajaro area. Dark brown 
 to gray, high in humus, twenty inches to four feet. SUBSOIL: Red- 
 dish yellow clay loam, hardpan, disintegrated shales. OCCURS: 
 Lower portions of ridges and hills, low hills. ORIGIN: Residual 
 from the underlying shales. CROPS: Grain, apples, raspberries, 
 blackberries, strawberries, pears, grapes. 
 
 WILLOWS LOAM. Mapped in the Colusa and Woodland areas. 
 Reddish gray, light red, yellow brown, some sharp sand, generally 
 well drained, ten to eighteen inches. SUBSOIL: Reddish brown clay 
 loam, compact, adobe-like. OCCURS in irregular shaped bodies, 
 sloping valley plains near foothills, uneven, hog-wallow mounds. 
 
Silt Loams Loams 133 
 
 ORIGIN: Alluvial, weathering of the sandstones of the foothills. 
 CROPS: Raisin, table, wine grapes, alfalfa, sugar beets, sorghum, 
 Egyptian corn, tree fruits, small fruits. Free from alkali. 
 YOLO LOAM. Mapped in the Woodland area. Dark brown, two 
 to six feet. SUBSOIL: Silty, or sandy, loam. OCCURS: Plains ele- 
 vated above surrounding areas, undulating ridges. ORIGIN: Depos- 
 ited by creek waters. CROPS: Peaches, almonds, prunes, grapes. 
 Rarely contains alkali. 
 
CHAPTER XVIII 
 SANDY ADOBES 
 
 GRAVELLY FINE SANDY LOAMS. STONY SANDY 
 
 LOAMS. GRAVELLY SANDY LOAMS. 
 
 GRAVELLY LOAMS. 
 
 Fine Coarse Medium Fine Very fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Placentia 2.0 4.1 .3.7 17.1 17.4 33.9 21.4 
 
 San Joaquin .... 1.1 4.5 12.1 23.2 22.1 23.9 10.5 
 
 Sierra 0.9 3.2 3.4 10.3 17.4 45.4 19.3 
 
 Average 1.3 3.9 6.4 16.9 18.9 34.4 17.0 
 
 As the name indicates, they contain the highest per cent of sand 
 of all the adobes. They contain also the least clay, and some fine 
 gravel and coarse sand. These benefit the soils, making them warmer, 
 lighter, better drained and aerated than the other adobes. They are, 
 however, still compact, sticky, retentive of moisture, heavy and difficult 
 to cultivate, and have a tendency to pack and bake. Under modern 
 methods of intense cultivation they are adapted to citrus and deciduous 
 fruits, berries and truck crops, as they are generally supplied with 
 organic matter, and naturally rich in plant food. 
 
 FULLERTON SANDY ADOBE. This name is no longer used. That 
 mapped as such in the San Bernardino and Ventura areas has beer 
 reclassified as Placentia sandy adobe, and that mapped under this title 
 in the Los Angeles and Santa Ana areas has been reclassified as Pla- 
 centia loam adobe. 
 
 PLACENTIA SANDY ADOBE. Mapped as Maricopa sandy adobe in 
 the Bakersficld area, and as Fullerton sandy adobe in the San Bernar- 
 dino and Ventura areas. Red to brown, three to six feet deep. SUB- 
 SOIL: Coarse, sandy adobe, shiny smooth sandy loam, decomposed 
 granite, decayed sandstone, cemented by iron oxides and hj'drates. 
 OCCURS on level to slightly sloping land, slightly dcpresed, on 
 undulating hills, not typical of any special physiographic feature 
 ORIGIN: From granite in place, colluvial wash from adjacent soils, 
 degradation of limestones. CROPS: Alfalfa, grain, some fruit. Gen- 
 erally free from harmful accumulations of alkali. 
 
 SAN JOAQUIN SANDY ADOBE. Mapped as San Joaquin red 
 adobe in the Fresno area. Bright red, six to ten feet. SUBSOIL: 
 Same but heavier, liardpan. ORIGIN; From the foothill adobe. 
 CROPS: Grain. 
 
 SIERRA SANDY ADOBE. Mapped as Sierra adobe in the Los 
 Angeles area. Reddish brown, medium to fine texture, one to three 
 
Sandy Adobes 135 
 
 feet deep SUBSOIL: Dark red, loam, gravelly loam, granite sand. 
 OCCURS on sloping plains. ORIGIN: Composed mainly of granitic 
 material deposited in Tertiary or earlier times. During the ear y 
 Pleistocene elevation of the land, the material was raised considerably 
 above its former level, and since then has been subjected to greater 
 wash and weathering. The red color is doubtless due to the oxidation 
 of the iron. CROPS: Dry farmed, citrus, deciduous fruits, berries, 
 and truck, around Los Angeles. 
 
 GRAVELLY LOAMS 
 
 Fine Coarse Medium Fine Veryflne 
 gravel sand sand sand sand Silt <-iay 
 
 Anderson 5 4 10 5 6 4 2., 8. 37 5 « 
 
 ?nX'"^ ■.■-:;:::. : : ^ m \ii ,]■} 'li 
 
 Maricopa 11.4 13.1 8.4 19.9 14 » ^^ g 
 
 Oxnard 0.9 1.6 1.3 b.9 lo ^4.2 
 
 Redding.. 4.9 8.3 4.8 li.u i^ ^3^2 
 
 San Joaquin .... 7.2 
 
 its i.2 12.9 8.6 36.0 
 
 TTT 14 8 lis 39.4 14.8 53.8 24.2 
 
 Highest 11.4 14.8 ll.« ^9.* ^^ ^^ 
 
 Lowest 0.9 1.6 l.rf ^-^ 32 g 14.8 
 
 Average 5.7 9.9 d.o 
 
 If soil contains from twenty to fifty per cent of silt and clay, they 
 are called gravelly loams, if they contain over fifty percent of fine sand 
 and gravel or over twenty-five per cent of fine gravel, coarse and me- 
 dium sand Th?se soils consist of sharp angular to water worn gravels 
 mTx™d with coarse and medium sands, The texture varies from loose 
 o compact according to the proportion of gravel present. They are 
 oose and porous to moderately heavy, and take water easily, but are 
 not retentive of it. Naturally well drained, they dry quickly. They 
 are friabk when cultivated and maintain an excellent tilth Jhe coarse 
 gravel gives them warmth, and they cool more slowly at night. 
 ANDERSON GRAVELLY LOAM. Mapped in the Redding area. 
 Moderately heavy, light red, eight to twelve /"^hes^ SUBSOIL. 
 Deeper red, six feet or more, stream gravels, medmni hardpam 
 CROPS: Used mainly for grazing; adapted to peaches and grapes if 
 well cultivated and irrigated. 
 
 ARBUCKLE GRAVELLY LOAM. Mapped in the Woodland area. 
 Gray brown, not analyzed. SUBSOIL: Brown loam clay loam. 
 OCCURS- Slopes bordering streams, broad undulatmg areas. 
 ORIGIN Due to the coarser material transported by streams crossmg 
 the plains. CROPS: Raisin grapes, fruit trees, general farm crops 
 when irrigated. 
 
 CORNING GRAVELLY LOAM. Mapped in the Red Bluff area. 
 Light red to yellowish red, medium texture, carries g^^^Y/^boggy when 
 wet comoact when dry; twelve to twenty inches. SUBSOIL. Kea, 
 compact heavyTlay or cky loam. OCCURS on sharply rolling ground, 
 hoQ- wallows ORIGIN: Wash from Red Bluff formation. CROF. 
 Grlzfug; under irrigation adapted to peaches, almonds, grapes, figs. 
 olives. 
 
136 Soils of California 
 
 INDIO GRAVELLY LOAM. Mapped as Imperial gravelly loam in 
 the Imperial area. Consists of gravel composed of agate, quartz, chert, 
 flint, limestone, granite, obsidian, and indurated clays, in size from a 
 fraction of an inch to five or six inches, six feet or more deep. SUB- 
 SOIL: Same with more clay. OCCURS: From the old Beach Line to 
 125 feet below sea level. ORIGIN: Derived from granitic rocks 
 mingled with some shale and sandstone material, and are formed by 
 colluvial and alluvial wash from intermittent or torrential streams, 
 wave action, torrents from mountains. CROPS: Valuable for fruits 
 suitable for the climate, where they can be irrigated. Little alkali 
 except in low places. 
 
 MARICOPA GRAVELLY LOAM. Mapped as Arroyo Seco sandy 
 loam in the San Jose and Lower Salinas areas. Mapped as San Gabriel 
 gravelly loam in the San Gabriel and Ventura areas. That mapped as 
 Maricopa gravelly loam in the Los Angeles area has been reclassified 
 as Maricopa fine sandy loam. Dark brown to black, locally yellowish, 
 sharp angular gravel, five to six feet deep. SUBSOIL: Sandy gravel. 
 OCCURS: On intermediate and upper slopes of valleys, base of abrupt 
 slopes along the lower edges of the mountains, comparatively level or 
 slightly rolling, rolling hills, alluvial fans. ORIGIN: Unassorted creep 
 soil from the mountain sides, from granite schists and allied rocks. 
 CROPS: Citrus fruits, vines, apricots, peaches, prunes, plums, almonds, 
 olives, and other stone fruits, black-eyed beans. 
 
 OXNARD GRAVELLY LOAM. Mapped as Salinas shale loam in 
 Ventura and Lower Salinas Valley areas. Brown to gray, simply shale 
 ground fine, chalky material, some boulders. SUBSOIL: Oxnard 
 loam. OCCURS: On table lands and fans, extending to the valleys as 
 a gently sloping plain, at the mouth of deep gullies. ORIGIN: Derived 
 from chalk-like siliceous shale, white or red, from Monterey shale 
 mixed with other material, carried down by flood waters. CROPS: 
 Lima beans, English walnuts, barley, wheat. Free from alkali. 
 
 REDDING GRAVELLY LOAM. Mapped in the Redding area. Red 
 to dark red, six to fifteen inches deep, carries small cobbles. SUB- 
 SOIL: Heavy, deep, adobe-like loam, hardpan. OCCURS: Uplands, 
 gently rolling. ORIGIN from early Pleistocene alluvium. CROPS: 
 Depends upon the nearness of the hardpan to the surface; peaches, 
 vines, grapes, strawberries; orchards if hardpan is dynamited. Free 
 from alkali. 
 
 SAN JOAQUIN GRAVELLY LOAM. Mapped in the Colusa and 
 Marysville areas, deep red to j'^ellowish red, twelve inches to six feet 
 deep. SU^BSOIL: Deep red, heavy, dense loam or clay loam. 
 OCCURS: On rolling plains, and slopes of lower foothills, marked by 
 hog-wallow mounds and knolls. ORIGIN: Alluvial and lacustrine 
 deposit, derived from the Red Bluff formation (Pleistocene). CROPS: 
 Grazing, dry farming to grain when drained; with intense cultivation, 
 adapted to fruits and vines. 
 
 TEHAMA GRAVELLY LOAM. Mapped in the Red Bluflf area. 
 Yellow brown to red gray. Compact to hard on drying, carries angular 
 rock fragments, eighteen to seventy-two inches. OCCURS: On bor- 
 
Sandt Adobes 137 
 
 dering intermittent streams, and as terraces and benches. ORIGIN: 
 Wash from higher lying soils, well drained. CROP: Grain; under 
 irrigation adapted to peaches, berries, almonds, apricots, melons, 
 alfalfa. 
 
 GRAVELLY FINE SANDY LOAM 
 
 Fine Coar.se Medium Fine Very fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Elder 3.0 7.6 9.6 38.6 11.8 23.4 5.9 
 
 Mocho 2.7 7.1 6.3 24.9 28.7 23.2 7.2 
 
 Vina 1.9 3.6 4.6 17.7 24.6 21.6 25.5 
 
 Average 2.5 6.1 6.8 27.0 21.7 22.7 12.9 
 
 ELDER GRAVELLY FINE SANDY LOAM. Mapped in the Red 
 BlufiF area. Gray, very variable in texture, porous, leachy, eighteen to 
 seventy-two inches. SUBSOIL: Sands and silts. OCCURS as 
 alluvial stream bottoms, overflowed, limited areas. VEGETATION: 
 Underbrush and tree growth. CROP: Pasture. 
 
 MOCHO GRAVELLY FINE SANDY LOAM. Mapped in the Liver- 
 more area. Brown, gray, gray yellow, ten to thirty-six inches. SUB- 
 SOIL: Coarse gravel. OCCURS: Base of hills, marked by abandoned 
 stream channels. ORIGIN: Alluvial. VEGETATION: Sycamore 
 trees. CROP: Grazing; adapted to truck and small fruit. 
 
 VINA GRAVELLY FINE SANDY LOAM. Mapped in the Red Bluff 
 area. Brown, variable texture, twenty to thirty inches. SUBSOIL: 
 Cobbles and volcanic materials. OCCURS on valley plains, surface 
 strewn with angular volcanic cobbles and boulders. ORIGIN: 
 Reworked product of the Tuscan soil. CROP: Grazing, grain. 
 
 STONY SANDY LOAM 
 
 TUSCAN STONY SANDY LOAM. Mapped in the Red Bluflf area. 
 Reddish to reddish brown; covered with boulders of volcanic material, 
 three to twelve inches. SUBSOIL: Cemented water-worn gravel. 
 OCCURS on land covered by recent volcanic flows. ORIGIN: Resi- 
 dual from lava. CROP: Non-agricultural except in small favored 
 areas. PHYSICAL ANALYSIS: Fine gravel 7.4, coarse sand 14.7, 
 medium sand 7.9, fine sand 11.7, very fine sand 16.9, silt 28.9, clay 12.3. 
 
 GRAVELLY SANDY LOAMS 
 
 Fine Coarse Medium Fine Very line 
 
 gravel sand sand sand sand Silt Clay 
 
 Arbuckle 9.2 12.1 9.1 22.9 16.1 22.4 7.7 
 
 Llvermore 10.1 10.5 6.7 12.0 11.7 36.8 12.2 
 
 Maywood 12.9 11.8 6.2 15.9 12.7 31.6 8.6 
 
 Pleasanton 8.5 11.5 7.2 12.9 13.8 32.1 14.1 
 
 Sacramento ....11.1 20.6 11.9 19.4 11.8 18.7 6.3 
 
 San Joaquin 6.6 17.7 9.0 13.1 8.8 31.9 12.9 
 
 Sites 4.1 8.8 6.7 18.1 18.6 31.8 12.0 
 
 Highest 12.9 20.6 11.9 22.9 18.6 36.8 14.1 
 
 Lowest 4.1 8.8 6.2 12.0 8.8 18.7 6.3 
 
 Average 8.9 13.2 8.1 16.3 13.3 29.3 10.5 
 
 These soils, as the name indicates, contain large proportions of 
 
138 Soils of California 
 
 the coarsest sands, and very little silt and clay, and are consequently 
 light, open, porous, and not retentive of water. 
 
 ARBUCKLE GRAVELLY SANDY LOAM. Mapped in the Wood- 
 land area. Gray to j^ellow brown, reddish brown to pink when wet, 
 four feet deep, boggy in wet weather. SUBSOIL: Gravelly clay loam, 
 gravelly clay. OCCURS: As narrow ridges along old stream beds, on 
 broad uniform slopes. ORIGIN: Alluvial. CROPS: Grape vineyards, 
 fruits. 
 
 LIVERMORE GRAVELLY SANDY LOAM. Mapped in the Liver- 
 more area. Dark brown, contains angular fragments of a great variety 
 of rocks, two to three feet. SUBSOIL: Same as soil, lighter in color, 
 coarser. OCCURS on benches along creeks. ORIGIN: Colluvial and 
 alluvial. VEGETATION: Valley oak, burr clover, alfilaria. CROP: 
 Hay, grain. 
 
 MAYWOOD GRAVELLY SANDY LOAM. Mapped in the Red 
 Bluff area. Gray brown, carries gravel, puddles slightlv when wet, six 
 feet. SUBSOIL: Gravel to loam. OCCURS: Bordering small inter- 
 mittent streams. ORIGIN: Alluvial wash. CROP: Adapted to olives, 
 oCcicHcs S-Iislfs. etc 
 
 PLEASANTON GRAVELLY SANDY LOAM. Mapped in the Liver 
 more area. Brown, contains angular cobbles, eighteen to thirty inches. 
 SUBSOIL: Reddish clav loam. OCCURS on rough hills broken by 
 deep ravines. ORIGIN: Sedimentary. VEGETATION: Field oak, 
 live oak, buckeve. CROP: Grazing. 
 
 REDDING GRAVELLY SANDY LOAM, flapped in the Red Bluff 
 area. Light red to red. sticky, carries medium to large gravel, twelve 
 to fourteen inches. SUBSOIL: Red clav loam, underlain by red clay. 
 OCCURS on low rolling hills. ORIGIN: A Pleistocene alluvial 
 deposit. VEGETATION: Upland oak and manzanita. CROP: Grain, 
 drj' farming; with irrigation it is adapted to berries, peaches, alfalfa. 
 Drainage poor. 
 
 SACRAMENTO GRAVELLY SANDY LOAM. Mapped in the Red- 
 ding and Colusa areas. Light brown to reddish brown, gray, contains 
 fragments of volcanic and metamorphic rocks. ORIGIN: From rocks 
 of volcanic and metamorphic origin; light to slightlv sticky, two to 
 six feet deep. SUBSOIL: Cobbles, gravel. OCCURS in irregular 
 bodies, long narrow strips, in gulches and ravines, across valley slopes, 
 marking the course of former streams, mixed with finer sediments. 
 CROPS: Peaches, fruit, grains, 
 
 SAN JOAQUIN GRAVELLY SANDY LOAM. Mapped in the 
 Madera area. Dark red, two to six feet. SUBSOIL: Hardpan. 
 OCCURS as pronounced ridges on plains. ORIGIN: Reworked 
 lacustrine material. CROP: Grain, grapes, figs, olives, probably citrus. 
 SITES GRAVELLY SANDY LOAM. Mapped in the Woodland 
 area. Yellow to red brown, heavy, well drained, fourteen to thirty 
 inches. SUBSOIL: Brown to red gravelly loam, heavy sandy loam, 
 weathered conglomerate or shale. OCCURS: Rolling, undulating, 
 knolls, and low hills. ORIGIN: Coarser grades of material from wash 
 or assorting action of water. CROPS: Grain, pasture, almonds, apri- 
 cots, grapes. 
 
CHAPTER XIX 
 FINE SANDY LOAMS 
 
 SANDY LOAMS. SILTY FINE SANDY LOAMS. 
 
 GRAVELLY SAND. GRAVEL. COARSE 
 
 SANDY LOAMS. LOAMY COARSE 
 
 SAND. COARSE SAND. 
 
 Fine Coarse Medium Fine Very fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Anderson 6.4 10.5 6.4 21.9 8.1 37.5 9.9 
 
 Arbuckle 0.4 5.8 10.6 33.3 20.5 17.1 12.1 
 
 Arnold 0.5 2.4 6.7 25.8 32.0 23.5 6.6 
 
 Fresno 0.0 2.4 6.7 25.8 32.0 23.5 6.6 
 
 Gila 0.0 0.5 1.2 16.4 26.2 38.7 16.6 
 
 Hanford 0.7 3.3 3.3 18.1 27.1 35.6 9.2 
 
 Indio 0.0 0.7 1.7 19.4 34.7 25.0 17.7 
 
 Madera 0.4 1.4 3.1 23.5 42.8 18.9 9.6 
 
 Maricopa 2.8 6.3 5.2 19.7 24.9 29.5 11.9 
 
 Maywood 1.8 2.6 2.7 15.1 37.4 30.4 9.6 
 
 Media 1.7 2.5 1.7 12.3 41.6 17.6 22.5 
 
 Mocho 0.0 0.2 1.0 21.0 26.0 41.5 10.0 
 
 Oriand 0.4 2.7 5.2 23.7 21.5 33.5 11.8 
 
 Oxnard 1.6 5.7 7.2 32.3 19.2 24.8 8.9 
 
 Pajaro 0.0 0.0 0.3 30.0 22.9 38.2 8.4 
 
 Placentia 4.2 8.0 7.0 19.1 19.6 28.3 12.1 
 
 Poplar 0.6 4.4 3.6 24.7 19.2 38.6 8.7 
 
 Sacramento .... 0.0 0.3 0.5 32.7 24.0 31.2 8.1 
 
 San Joaquin 1.0 7.8 7.7 25.3 16.3 27.2 14.4 
 
 Santiago 1.7 4.8 5.3 25.9 26.9 26.7 6.6 
 
 Stockton 1.0 3.4 11.4 22.6 24.3 22.8 10.8 
 
 Ulmar 0.4 6.0 4.8 20.7 21.0 32.9 10.0 
 
 Vina 0.5 2.6 5.7 27.1 33.8 22.1 7.8 
 
 Yolo 0.2 1.2 2.2 25.2 36.3 23.3 11.6 
 
 Higiiest 5.4 10.5 11.4 33.3 42.8 41.5 22.5 
 
 Lowest 0.0 0.0 0.3 12.3 8.1 17.1 6.6 
 
 Average 1.0 3.2 4.6 23.4 26.6 28.7 10.4 
 
 If soils contain from twenty to fifty per cent of silt and sand they 
 are called fine sandy loam, if they contain over fifty per cent of fine 
 sand, or less than twenty-five per cent of fine gravel, coarse and 
 medium sand. 
 
 They are the most important soils of the state on account of the 
 variety, yield and value of intensively cultivated crops, and are adapted 
 to any crop suited to the local and climatic conditions. They are 
 smooth, loose, porous, light and friable, and generally well drained on 
 account of their texture giving ready percolation. They possess strong 
 capillary power and are moderately rententive of moisture under culti- 
 vation, but are sometimes sticky when too wet, packing some and hav- 
 ing a tendency to puddle. At first they were used only for grazing and 
 dry farming; later, alfalfa, barley, wheat, potatoes, etc., were planted 
 
140 Soils of Califobnia 
 
 extensively; but they are now noted for their special crops, under irri- 
 gation and intensive cultivation, of citrus, olives, walnuts, peaches, 
 pears, wine and raisin grapes, hops, asparagus, sugar beets, melons, 
 strawberries, peanuts, etc., etc. 
 
 ANDERSON FINE SANDY LOAM. Mapped in the Redding area. 
 Light red to reddish gray, three to six feet. SUBSOIL: River sands, 
 hardpan, clays, volcanic tuflf. CROPS: Adapted to peaches, pears, 
 grapes, small fruits, dry farming, grain. 
 
 ARBUCKLE FINE SANDY LOAM. Mapped in the Woodland area. 
 Brown, six feet. SUBSOIL: Sandy or silty loam, gravel, yellowish 
 brown. OCCURS: Level, well drained. ORIGIN: Alluvial. CROPS: 
 Fruit and garden. 
 
 ARNOLD FINE SANDY LOAM. Mapped in the Modesto-Turlock 
 area. Chocolate brown, micaceous, contains some gravel, three to 
 five feet deep. SUBSOIL: Similar to the soil but heavier. OCCURS 
 on the crest of hills, above river terraces. ORIGIN: Alluvial, lacus- 
 trine. CROPS: Grain, adapted to fruit, vegetables, grapes. 
 FRESNO FINE SANDY LOAM. Mapped in the Indio, Modesto-Tur- 
 lock, Madera, and Stockton areas. Mapped as Fresno sandy loam in 
 the Fresno area. That mapped as Fresno fine sandy loam in the Bak- 
 ersfield, Los Angeles, Lower Salinas Valley, San Bernardino, and San 
 Gabriel areas has been reclassified as Hanford fine sandy loam. That 
 mapped as Fresno fine sandy loam in the Ventura area has been 
 reclassified as Oxnard loam. That mapped as Fresno fine sandy loam 
 in the San Jose area has been reclassified as Hanford silt loam. Light 
 gray, ashy, fifteen inches to five feet deep. Called "White Ash Land" 
 around Fresno. SUBSOIL: White to bluish hardpan. OCCURS: In 
 irregular, elongated areas, surface low, flat, or slightly depressed. 
 ORIGIN: Derived from white sands, volcanic ash, and granitic 
 material. CROPS: Mainly given to grazing, where well drained 
 grains, vines and small fruits do well; alfalfa, vines, figs, peaches, ber- 
 ries, melons; valuable fruit land around Selma. The alkali in the sub- 
 soil makes it sometimes difficult to reclaim the land where the drainage 
 is poor. 
 
 GILA FINE SANDY LOAM. Mapped in the Imperial area. Mapped 
 as Imperial sandy loam in the Yuma-California area. Reddish brown, 
 three to six feet deep. SUBSOIL: Light loam or sandy loam which in 
 turn is underlain by loam, clay loam, clay or sand. OCCURS: Level, 
 or slightly scored by the wind. ORIGIN: Direct deposit from rivers; 
 and sand blown or washed in from the mesas. CROPS: Adapted to 
 all the field and fruit crops suitable for the climate. One of the best 
 soils in Imperial Valley. Generally free from alkali. 
 
 HANFORD FINE SANDY LOAM. Mapped in the Hanford, Madera 
 and Woodland areas. Mapped as Fresno fine sandy loam in the Bak- 
 ersfield, Sacramento, Santa Ana, Salinas Valley, San Bernardino, and 
 San Gabriel areas. Light to dark gray or drab, brown, bufif, yellowish 
 reddish, six feet deep. SUBSOIL: Very variable, often sand. 
 OCCURS: In local depressions, near slouughs or drainage basins, on 
 the lower terraces and river bottoms subject to overflow, on level delta 
 
Fine Sandy Loam 141 
 
 plains, adjacent to river and slough channels and tidal flats. ORIGIN: 
 From the fine micaceous material derived from granitic, diabasic and 
 other fine textured rocks of the foothills and mountains deposited over 
 the flood plains from the slack waters of the streams. CROPS 
 Among the most important on account of the variety, value, and yield 
 adapted to any crops suited to the local climatic conditions; walnuts 
 citrus, apples, pears, celery, sugar beets, raisin grapes, hops, asparagus, 
 alfalfa, grain, potatoes, truck. There is rarely enough alkali to exclude 
 useful crops. 
 
 INDIO FINE SANDY LOAM. Mapped as Fresno fine sandy loam in 
 the Indio area. Slate colored, two to five feet. SUBSOIL: Sandy 
 loam, sand. OCCURS: Uniform slopes, from 250 feet below sea level 
 to 100 above. ORIGIN: Same as Indio fine sand. CROPS: The best 
 for general purposes; melons, sweet potatoes, garden crops, etc. Some 
 alkali in spots. 
 
 LIVERMORE FINE SANDY LOAM. Mapped in the Livermore 
 area. Brown, variable texture, two feet. SUBSOIL: Yellow sandy 
 loam. OCCURS in ridges marking the course of former streams. 
 Well drained. ORIGIN: Colluvial and alluvial. CROP: Dry farmed 
 to grain a~nd hay. Adapted to small fruit, truck, alfalfa. 
 MADERA FINE SANDY LOAM. Mapped in the Madera area. 
 Brown, fifty to sixty inches. OCCURS on lowlands bordering streams. 
 ORIGIN: Alluvial. CROP: Grain; adapted to alfalfa, grapes, small 
 fruit. 
 
 MARICOPA FINE SANDY LOAM. Mapped as Maricopa gravelly 
 loam in the Los Angeles area. Dark brown to brown, gravel, pebbles 
 and cobbles, three to six feet. SUBSOIL: Waterworn granitic sand, 
 gravel and boulders. OCCURS: Level terraces along streams, sloping 
 plains. ORIGIN: Granitic material brought from the mountains by 
 river and streams. CROPS: Grapes, strawberries, oranges, peaclies, 
 apricots, alfalfa, etc. Free from alkali. 
 
 MAYWOOD FINE SANDY LOAM. Mapped in the Red Blufif area. 
 Yellowish gray, friable, does not puddle or crack, twenty-four to thirty 
 inches. SUBSOIL: Loam or gravelly loam. OCCURS: Bordering 
 streams, level, well drained. ORIGIN: Wash from higher soils. 
 CROP: Alfalfa, peaches, prunes, apricots, melons, truck. 
 MEDIA FINE SANDY LOAM. Mapped in the Madera district. Red, 
 two to six feet. SUBSOIL: Clay loam. OCCURS on rolling land. 
 ORIGIN: Residual. CROPS: Grain; locally to grapes, figs, olives, 
 alfalfa. 
 
 MOCHO FINE SANDY LOAM. Mapped in the Livermore area. 
 Brown to gray brown; eighteen to twenty-four inches. OCCURS 
 along stream channels. ORIGIN: Alluvial from overflow of creeks in 
 flood. CROP: Sugar beets, truck. 
 
 ORLAND FINE SANDY LOAM. Mapped in the Colusa area. Red- 
 dish to reddish gray, few inches to three feet deep. SUBSOIL: Under- 
 lain by partially weathered sandstone. OCCURS: On elevated foot- 
 hill ridges, steep slopes, unirrigable. ORIGIN: Residual, derived from 
 sandstone in place. CROPS: Dry farming; grain, grazing, adapted to 
 
142 Soils of California 
 
 fruits, vegetables, and sugar beets under irrigation. Free from alkali. 
 OXNARD FINE SANDY LOAM. Mapped in the San Bernardino 
 area. Greenish gra}% micaceous, some gravel, one to two feet deep. 
 SUBSOIL: Heavy, sticky, gray sandy loam, or loam. OCCURS: 
 Smooth, level. ORIGIN: Wash from incoherent sandstones which 
 weather into fantastic shapes locally called "Bad Lands." CROPS: 
 Wheat, alfalfa. Alkali where poorly drained. 
 
 PAJARO FINE SANDY LOAM. xVIappcd in the Pajaro area. Brown, 
 micaceous, eighteen to seventy two inches. SUBSOIL: Black loam, 
 or silt loam. OCCURS along the rivers and creeks. ORIGIN: Allu- 
 vial and sedimentary. CROPS: Apples, alfalfa, tomatoes, beans, sugar 
 beets, cantaloupes, cucumbers, strawberries, loganberries, blackberries. 
 PLACENTIA FINE SANDY LOAM. Mapped as Placentia sandy 
 loam in the Los Angeles, Lower Salinas Valley, San Bernardino, San 
 Jose, San Gabriel and Santa Ana areas. Reddish brown, brown, red- 
 dish yellow, eighteen inches to six feet deep. The Gravelly Phase con- 
 tains a high percent of gravel. SUBSOIL: Hardpan, compact loam, 
 sandy adobe. OCCURS in large bodies on hills, level to steep, low 
 rolling hills, mesas, mountain slopes, coastal plains. ORIGIN: The 
 origin of this soil is similar to that of many others and may be used as 
 an illustration of the origin of sandy loams in general. The greater 
 part has been found in place, but some is due to soil-creep from the 
 base of the hills. In the Lower Salinas Valley, bordering the Gavilan 
 Range, and Sierra Salinas, it is derived from Jurassic and older rocks 
 consisting chiefly of fragments of gneiss, schists and granites, brought 
 down and distributed by torrential streams from canyon mouths. In 
 the Los Angeles area it is the weathered product of granitic material 
 that was transported, as above, in late Tertiary times. These old 
 washings of Pleistocene times were elevated by a movement of the 
 earth's crust, and have since then been much modified by weathering. 
 They have also been wind blown along the coast. In the San Jose 
 area the line material has been carried a long distance along the slope 
 of the mountains and the alluvial fans, or cones, extending outward 
 from canyon mouths. These cones often merge and form broad gently 
 sloping mesa lands. Where the sandy loam is the result of the break- 
 ing down of sandstone or conglomerate the soil contains gravel and 
 assumes a gravelly phase as in the San Gabriel area where the soil 
 north of Puente is formed partially from the wash of Walnut Creek, 
 which drains a sandstone and shale area, and partially from the wash 
 of San Dimas Canyon, which drains a granitic area. CROPS: Citrus 
 fruits at Riverside, Redlands, Whittier, La Mirada, Santa Fe Springs, 
 Montebello, Pico Heights, Palms, Inglevvood, Gardena, San Dimas, 
 and in Orange County, walnuts at Whittier, olives, grapes, truck, ber- 
 ries, alfalfa, grain, prunes, peaches, wine grapes, cherries, etc. Gener- 
 ally free from alkali. 
 
 POPLAR FINE SANDY LOAM. Mapped in the Portersville area. 
 Light brown to bufif, micaceous, two to four feet deep. SUBSOIL: 
 Reddish or yellowish brown clay loam. OCCURS: In small irregular 
 patches, level. ORIGIN: Alluvial, the subsoil is reworked Pleistocene 
 material mixed with recent material. CROPS: Pasturage, dairying, 
 
Fine Sandy Loam 143 
 
 alfalfa, small fruits, deciduous fruits, truck gardens. Practically free 
 from alkali. 
 
 SACRAMENTO FINE SANDY LOAM. Mapped in the Colusa. 
 Woodland, Redding, Red Bluff, and Sacramento areas. Light gray to 
 dark brown, micaceous, eighteen inches to six feet. SUBSOIL: 
 Gravels, sandy loams. OCCURS in irregular, narrow, elongated 
 bodies, near stream channels, sloughs, uneven, sloping. ORIGIN: 
 Recent alluvial. CROPS: Alfalfa, peaches, prunes, pears, plums; 
 melons, hops, potatoes, corn, English walnuts, wheat, barley. 
 SAN JOAQUIN FINE SANDY LOAM. Mapped in the Colusa, 
 Marysville and Sacramento areas. Light red to buf¥, ten inches to three 
 feet. SUBSOIL: Red loam, light brown clay loam, heavy indurated 
 clay. OCCURS: In irregular shaped bodies, on undulating and smooth 
 valley plains, upper benches of ancient flood plain. ORIGIN: Lacus- 
 trine, from Red Bluff formation. CROPS: Grazing, grain; with irri- 
 gation adapted to grapes, citrus fruits, stone fruits, berries, Tokay 
 grapes, strawberries. 
 
 SANTIAGO FINE SANDY LOAM. Mapped as Santiago sandy 
 loam in the Santa Ana area, three to four feet deep. SUBSOIL: Sand 
 twelve to thirty feet, sand adobe. OCCURS on the higher elevations, 
 uplands, broken country. CROPS: Truck, peanuts, wheat, barley, 
 small fruits, oranges and walnuts at Orange and Tustin. 
 STOCKTON FINE SANDY LOAM. Mapped as Fancher sandy 
 loam in the Fresno area. Red, micaceous, high percent of organic 
 matter, six feet deep. SUBSOIL: Same, gravelly. OCCURS along 
 foothill streams, around sinks, in low lying tracts. ORIGIN: Result 
 of stream deposits. CROPS: Typical raisin soil. Minor spots of 
 alkali. 
 
 ULMAR FINE SANDY LOAM. Mapped in the Livermore area. 
 Brown, thirty to seventy-two inches. SUBSOIL: Yellow fine sandy 
 loam with hardpan at from three to five feet. OCCURS on valley 
 floor, marked by old stream channels and some hogwallows. 
 ORIGIN: Colluvial and alluvial. VEGETATION: Greasewood, alkali 
 heath, salt grass. Some alkali. CROPS: Grazing, hay, grain. 
 VINA FINE SANDY LOAM. Mapped in the Red Blufif area. Dark 
 grey to gray brown, micaceous, uniform texture, six feet. SUBSOIL: 
 Gravel. OCCURS on sloping valley plains, bordering streams, marked 
 by old channels, poorly drained. ORIGIN: Alluvial, recent deposit of 
 streams. VEGETATION: Oak, willow, grapevines. CROPS: Alfalfa, 
 peaches, wine grapes, truck, melons, stone fruits. 
 
 YOLO FINE SANDY LOAM. Mapped in the Woodland area. Light 
 brown, contains streaks of sand and thin beds of silt, surface some- 
 times contains wind-blown sand, fifteen inches. SUBSOIL: Brown 
 sand, sandy loam, loam, silt loam. OCCURS as numerous small 
 bodies, sloping or slightly undulating, between creeks, lower bench 
 lands. ORIGIN: Recent from the shifting currents of the larger 
 creeks during flood periods. CROPS: Alfalfa, vines, grain, peaches, 
 apricots, almonds, grapes, prunes, truck gardens, sugar beets, general 
 farm crops. 
 
144 
 
 Soils of Califobnia 
 
 SANDY LOAMS 
 
 Fine Coarse Medium Fine Very fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Arnold 10.2 29.4 10.3 12.4 3.5 24.6 9.6 
 
 Bellavista 0.0 6.6 20.1 44.6 4.8 15.0 7.9 
 
 Contra Costa ... 3.8 19.1 16.3 20.3 8.8 22.7 8.9 
 
 Encina 2.1 13.9 19.7 26.5 13.7 16.7 7.5 
 
 Exeter 4.3 17.1 7.8 17.5 7.3 31.7 14.5 
 
 Fresno 1.1 7.4 6.7 21.0 16.2 35.9 9.9 
 
 Gridley 5.0 20.6 14.2 26.1 8.0 16.0 10.2 
 
 Hanford 7.6 25.1 12.9 34.5 7.1 10.2 3.0 
 
 Imperial 0.0 0.2 0.4 9.3 20.3 47.6 15.4 
 
 Madera 1.7 22.0 18.5 21.1 9.6 19.1 7.9 
 
 Maricopa 10.1 19.0 11.5 21.0 12.4 17.1 8.8 
 
 Media 6.4 12.9 7.3 24.5 25.2 16.5 7.2 
 
 Monterey 0.1 7.0 22.4 35.3 1.7 23.1 10.3 
 
 Oaltdale 5.2 22.1 10.1 21.8 9.1 24.6 7.6 
 
 Oxnard 0.3 2.2 3.4 19.1 26.4 34.2 10.3 
 
 Pajaro 0.1 7.0 16.6 37.1 4.9 24.4 9.3 
 
 Placentia 10.6 13.2 6.7 19.1 20.6 18.9 10.7 
 
 Pleasanton 3.4 9.1 6.9 18.1 20.8 30.6 11.2 
 
 Sacramento . . . . 0.7 14.2 10.1 40.4 11.5 14.6 8.4 
 
 San Joaquin .... 4.0 10.5 10.6 18.2 20.2 23.6 10.9 
 
 Santa Cruz 0.3 17.4 22.5 36.0 3.4 10.0 10.3 
 
 Sheridan 2.5 10.9 8.0 31.0 18.7 16.8 11.2 
 
 Sierra 13.0 23.6 10.0 17.6 7.4 15.0 12.8 
 
 Sites 0.0 6.0 9.4 26.6 11.0 27.6 19.4 
 
 Sutter 4.6 11.5 6.8 24.3 14.4 24.3 14.1 
 
 Watsonville .... 0.1 3.1 4.5 17.5 7.2 55.8 11.3 
 
 Highest 13.0 29.4 22.5 44.6 26.4 55.8 19.4 
 
 Lowest 0.0 0.2 0.4 9.3 1.7 10.0 3.0 
 
 Average 3.7 16.1 12.9 24.7 12.5 23.7 10.2 
 
 When soils contain from twenty to fifty per cent of silt and clay 
 they are called sandy loam. If they contain over twenty-five per cent 
 of fine gravel, coarse and medium sand, they are light and mellow and 
 usually of fine texture, but may vary widely in this respect. They are 
 often hard and compact when dry, compact and sticky or plastic, with 
 a tendency to pack when wet, but loose and friable under cultivation. 
 They take water well but become heavier under irrigation, being 
 easily cultivated when handled at the right time; but when too moist 
 break up into clods. The drainage depends upon local conditions, and 
 they are apt to wash under heavy rains. With thorough artificial 
 drainage and plenty of irrigating waters they make a fine soil for fruit 
 and general farming, forming a moisture-retaining mulch when culti- 
 vated. Only depressed areas incapable of drainage and irrigation are 
 of no agricultural importance. 
 
 ARNOLD SANDY LOAM. Mapped in the Modesto-Turlock area. 
 Gray to brown, contains coarse granite and quartz sand and pebbles. 
 SUBSOIL: Yellowish red, clay, coarse sand and silt. OCCURS: Any 
 place in the foothills. ORIGIN: Lacustrine and alluvial. CROPS: 
 Dry farming, adapted to grapes, olives, almonds, and figs if properly 
 managed. 
 
 BELLAVISTA SANDY LOAM, Mapped in the Redding area. Light 
 ash-gray, well drained, one to six feet. SUBSOIL: Adobe-like sandy 
 clay, a clay hardpan, volcanic ash and tuff. OCCURS: Occupies gently 
 sloping valley plains or lower rolling hill slopes. ORIGIN: From the 
 
Fine Sandy Loam. 145 
 
 erosion of adjacent beds of volcanic ash and tuflf and the distribution of 
 this material with the gravels and soils derived from the uplands. 
 CROPS: Of limited acreage and minor agricultural importance. 
 CONTRA COSTA SANDY LOAM. Mapped in the Livermore area. 
 Brown when wet, yellowish when dry, twelve to sixty inches. SUB- 
 SOIL: Bedrock. OCCURS on low broken hills. ORIGIN: Residual 
 from coarse grained sandstone and conglomerate. VEGETATION: 
 Live oak, field oak. CROP: Grain, hay, adapted to eucalyptus. 
 DAULTON SANDY LOAM. Mapped in the Madera area. Grayish 
 to dark brown, live to forty-eight inches. SUBSOIL: Metamorphic 
 rocks or granite. OCCURS on eroded steep rolling lands or foothills. 
 ORIGIN: Residual. CROPS: Grazing. 
 
 ENCINA SANDY LOAM. Mapped in the Pajaro area. Drab gray 
 to dark brown, coarse, sharp fragments of granite, quartz and shale, 
 two feet. SUBSOIL: Gray heavy sandy loam, sandy adobe. 
 OCCURS: Slopes of the foothills. ORIGIN: Residual. CROPS: 
 Grapes, apples, apricots. 
 
 EXETER SANDY LOAM. Mapped in the Portersville area. Dark to 
 
 reddish brown, fine gravel, drainage good, six feet. SUBSOIL: Simi- 
 lar but more compact. OCCURS: Level. ORIGIN: Wash from the 
 adjacent soils, recent alluvial. CROPS: Grain, citrus fruits, grapes, 
 peaches. Free from alkali. 
 
 FRESNO SANDY LOAM. Mapped in the Hanford and Modesto- 
 Turlock areas. That mapped as Fresno sandy loam in the Fresno area 
 is Fresno fine sandy loam. That in the Indio area is Indio fine sand, 
 called "White Ash Land" in many parts of the San Joaquin Valley. 
 White to gray, fine ash, two to three feet. SUBSOIL: Lime-mag- 
 nesium hardpan, contains salt and alkali. OCCURS: In irregular- 
 shaped bodies. ORIGIN: Derived from white sands, volcanic ash, 
 and granitic material. CROPS: With thorough artificial drainage and 
 plenty of irrigating water makes a fine soil for fruit and general farm- 
 ing; grain, alfalfa, figs, peaches, olives, berries, vines, melons, vege- 
 tables, etc. Alkali in depressed areas. 
 
 GRIDLEY SANDY LOAM. Mapped in the Marysville area. Red- 
 dish brown, contains waterworn gravel, thirty inches to six feet, drain- 
 age good. SUBSOIL: Dark brown sticky loam. OCCURS: Level to 
 slightly rolling. ORIGIN: Sedimentary, reworked by later alluvial 
 agencies. CROPS: Pasture, grain, peaches, grapes, alfalfa, berries. 
 
 HANFORD SANDY LOAM. Mapped in the Madera and Porters- 
 ville area. Mapped as Fancher sandy loam in the Hanford area, gray 
 to buflf, six feet. SUBSOIL: Yellow or sticky loam. OCCURS in 
 elongated irregular bodies, level or uniform surface, along streams, 
 delta plains, coastal plains, lower terraces, valley floors. ORIGIN: 
 Alluvial, granitic material from the mountains reworked and deposited 
 by streams during floods. CROPS: Alfalfa, grain, deciduous fruits, 
 grapes, general utility soil. Traces of alkali. 
 
 IMPERIAL SANDY LOAM. Mapped in the Imperial area. Coarse 
 river sediment, three feet. SUBSOIL: Heavy sandy loam, loam. 
 OCCURS in large bodies, irregular in form. ORIGIN: Colorado 
 
146 Soils of California 
 
 River deposits, mixed with wind-blown sand. CROPS: Best for inter- 
 tillage crops, fruits, dates, sugar beets, vegetable and general utility. 
 Wide range of alkali conditions; some areas free, others badly affected. 
 MADERA SANDY LOAM. Mapped in the Madera area. Brown, 
 one to six feet. SUBSOIL: Red hardpan. OCCURS on rolling or 
 dissected plains, marked by hogwallows. ORIGIN: Reworking of 
 older residual soils. CROP: Grain, grazing, local adapted to figs, 
 olives, berries, alfalfa. 
 
 MARICOPA SANDY LOAM. Mapped in the Los Angeles area. 
 Mapped as San Gabriel sandy loam in the San Bernardino area. Light 
 gray to yellowish, brown to reddish, three to six feet. OCCURS on 
 hill and mountain slope. ORIGIN: Residual, coUuvial, detritus from 
 granite and closely allied rocks. CROPS: Citrus and deciduous fruits, 
 peas, beans, tomatoes, egg plant, squashes, potatoes, peppers, pine- 
 apples at Hollywood. 
 
 MEDIA SANDY LOAM. Mapped in the Madera area. Red to gray 
 red micaceous, carries angular fragments of feldspar, thirty to sixty 
 inches. SUBSOIL: Granitic rocks. OCCURS on rolling land cut by 
 intermittent stream courses. ORIGIN: Residual. CROP: Grain, 
 grazing; local adapted to grapes, figs, olives, alfalfa; possibly to citrus. 
 MOCHO SANDY LOAM. Mapped in the Livermore area. Brown 
 to gray, frequently consists of alternating strata of silty fine sand, fine 
 and coarse sand; three to six feet. SUBSOIL: Brown to black clay, 
 clay loam. OCCURS in long narrow strips along stream channels. 
 ORIGIN: Alluvial by overflow of creeks. VEGETATION: Syca- 
 more, oak, willow. CROPS: Peas, potatoes, cabbages, truck. 
 MONTEREY SANDY LOAM. Mapped in Pajaro area. Brown, 
 darkened by humus, thirty inches. OCCURS: Broken, hilly, exposed 
 slopes, ridges of the foothills of the Coast Range. ORIGIN: From 
 the underlying shaly sandstones, and wash from higher ground. 
 CROPS: Apricots, orchards where well cultivated. 
 
 OAKDALE SANDY LOAM. Mapped in the Modesto-Turlock area. 
 Chocolate brown, micaceous, contains coarse sharp sand, five to six 
 feet. SUBSOIL: White hardpan. OCCURS: Smooth, level. 
 ORIGIN: Mingling of the material from adjacent soils. CROPS: 
 Fine for fruit and general farming; figs, peaches, olives, berries, 
 melons, vegetables, etc. 
 
 OXNARD SANDY LOAM. Mapped in the San Bernardino and Ven- 
 tura areas. Dark brown to black, light, high in organic matter, drain- 
 age poor in places, four to five feet. GRAVELLY PHASE: Contains 
 shale gravel. SUBSOIL: Heavy sandy loam, loam, unconsolidated 
 sandstones. OCCURS: Level, slightly undulating, gentlj' sloping 
 plains, deltas, capping unconsolidated sandstones. ORIGIN: Wash 
 from shale and sandstones. CROPS: Sugar beets, grain, truck crops, 
 lima beans. May contain small amounts of alkali, rarely 0.20 per cent. 
 PAJARO SANDY LOAM. Mapped in the Pajaro area. Dark brown, 
 easily tilled, six feet. SUBSOIL: Lighter in color and texture. 
 CROPS: Excellent orchard soil, apples, cherries, prunes, plums, pears, 
 walnuts, strawberries, raspberries, loganberries, blackberries, when 
 irrigated. 
 
Fine Sandy Loam 147 
 
 PLACENTIA SANDY LOAM. Mapped in the Bakersfield area. 
 Mapped as Placentia loam in the Ventura area. Mapped as Placentia 
 coarse sandy loam in the San Bernardino area. That mapped as Placen- 
 tia sandy loam in the San Bernardino, Los Angeles, San Jose, San Ga- 
 briel, Santa Ana, and Lower Salinas Valley area has been reclassified as 
 Placentia fine sandy loam. Coarse, compact, well drained, three to 
 four feet. SUBSOIL: Red, heavy, coarse and hard sandy loam. 
 OCCURS: On the gentle slopes from the foothills. ORIGIN: Col- 
 luvial, from waste of the foothills. CROPS: Alfalfa, local small 
 orchards. Usually free from harmful accumulations of alkali. 
 PLEASANTON SANDY LOAM. Mapped in the Livermore area. 
 Reddish brown, sticky; forms a surface crust after rains. OCCURS at 
 base of eastern slope of the Coast Range; level to rolling, limited. 
 ORIGIN: Sedimentary. CROP: Dry farmed to hay, grain, grapes. 
 SACRAMENTO SANDY LOAM. Mapped in the Modesto-Turlock 
 area. Brown, gray, micaceous, six feet. SUBSOIL: Coarse sand or 
 gravel. OCCURS: Comparatively level, along rivers. ORIGIN: 
 Deposited during recent overflows. CROPS: Orchards, gardens, 
 truck gardening, berries, melons. 
 
 SAN JOAQUIN SANDY LOAM. Mapped in the Stockton, Sacra- 
 mento, Marysville, Madera, Fresno, Modesto-Turlock, and Porters- 
 villa areas. Light red, silty, drainage variable, eighteen inches to six 
 feet. SUBSOIL: Fine dense hardpan, red, yellow, heavy compact gray 
 sandy adobe; sandstone, hardpan. OCCURS: On gentle slopes, flood 
 plains, valley floors, on hogwallow land. ORIGIN: Pleistocene lake 
 deposits modified by alluvial wash, from adjacent granitic, volcanic 
 and metamorphic rocks washed into the Pleistocene lake or bay. 
 CROPS: Vary widely locally; hay, oats, barley, rye, peaches, cherries, 
 plums, citrus fruits, Zinfandel, Tokay, Emperor, and seedless grapes. 
 Alkali not present in injurious quuantities. 
 
 SAN JOAQUIN SANDY LOAM. Mapped in the Madera area. Red 
 to yellow brown, eighteen to seventytwo inches. SUBSOIL: Red fer- 
 ruginous hardpan. OCCURS on plains marked by hogwallows, poorly 
 drained. ORIGIN: Lacustrine. CROP: Grain, figs, olives, grapes. 
 SANTA CRUZ SANDY LOAM. Mapped in the Pajaro area. Dark 
 red, red brown, two to three feet, high iron contents. SUBSOIL: 
 Heavy reddish sandy loam. OCCURS: Steep hillsides. ORIGIN: 
 From sandstones in place. CROPS: Apples, wine grapes. The "red- 
 wood soils" produce the best orchards. 
 
 SHERIDAN SANDY LOAM. Mapped in the Sacramento area. 
 Black, micaceous, drainage variable, six inches to six feet. SUBSOIL: 
 Granitic, stream gravels. OCCURS: Lower valley slopes of the foot 
 hills. ORIGIN:' Residual or colluvial from the weathering of dark 
 colored, fine textured gabbrodiorite and grannodiorite. CROPS: When 
 well drained adapted to grains, hay, forage crops, fruit. 
 
 SIERRA SANDY LOAM. Mapped in the Sacramento area. Light 
 gray to red, coarse, well drained, three to six feet. OCCURS: Covers 
 the rolling, dome-like slopes of the lower foothills, rock outcrops. 
 ORIGIN: Disintegration in place of grannodiorite rock. CROPS: 
 
148 Soils of California 
 
 Berries, vines, citrus fruits, deciduous fruits, peaches, plums, cherries, 
 apricots, pears, strawberries, etc., according to local climate. No 
 injurious amount of alkali. 
 
 SITES SANDY LOAM. Mapped in the Colusa area. Light red to 
 reddish gray, well drained, three to six feet. SUBSOIL: Sandstone. 
 OCCURS: Elevated foothill ridges, broken, outcrops of sandstones. 
 ORIGIN: Residual from sandstone in place. CROPS: Grain, grazing. 
 Free from alkali. 
 
 SUTTER SANDY LOAM. Mapped in the Marysville area. Brown, 
 rarely black, three inches to si.\ feet. SUBSOIL: Yellow, brown, 
 sticky. OCCURS: In irregular areas, around the edges of buttes, in 
 small valleys and coves; occasionally overflowed by backwaters. 
 ORIGIN: Largely colluvial, altered by flood material, weathered andes- 
 itic rocks, tuffs, breccias. CROPS: Grain, alfalfa, almonds, peaches, 
 berries, melons. Free from alkali. 
 
 WATSONVILLE SANDY LOAM. Mapped in the Pajaro area. Red- 
 dish brown, sharp angular sand, thirty inches to six feet, high in iron 
 salts, drainage good. SUBSOIL: Dark red, heavy sandy loam, sandy 
 shales, heavy silty clay loams. OCCURS: Uplands, lower portions of 
 Coast Range. ORIGIN: Residual, from underlying shales and con- 
 glomerates. CROPS: Grain, apples, apricots, grapes, eucalyptus. 
 
 SILTY FINE SANDY LOAM 
 
 LIVERMORE SILTY FINE SANDY LOAM. Mapped in the Liver- 
 more area. Brown, thirty-si.\ inches. SUBSOIL: Yellowish sandy 
 loam. OCCURS on level to slightly rolling land with ridges, and for- 
 mer stream channels. ORIGIN: Colluvial and alluvial. CROPS: 
 Orchard fruits, truck farms, alfalfa. PHYSICAL ANALYSIS: Fine 
 gravel 0.0, coarse sand 0.2, medium sand 0.5, fine sand 14.6, very fine 
 sand 32.8, silt 41.9, clay 9.9. 
 
 GRAVELLY SAND 
 MARICOPA GRAVELLY SAND. Mapped as San Gabriel gravelly 
 
 sand in the San Gabriel area, as Soledad gravelly sand in the Salinas 
 area, and as San Gabriel gravelly sand in the San Bernardino area. 
 Light to dark gray, yellowish to brown, from fine sand to pieces two 
 and three inches in diameter; the fine gravel predominates over all the 
 other units; six feet. SUBSOIL: Same as soil, only more compact. 
 OCCURS on steep slopes, at foot of mountains. ORIGIN: Granitic 
 wash, direct from the mountains. CROPS: Citrus fruits, grapes, 
 peaches, apricots. Free from excess of alkali. 
 
 GRAVEL 
 HANFORD GRAVEL. Mapped as Fresno gravel in the Sacramento 
 area. The true gravel soil is composed of all grades of gravel and 
 cobbles, with some small boulders, underlain by the prevailing rock of 
 the locality. OCCURS along the lower river benches, on sloping hill- 
 sides, and in ravines. ORIGIN: Derived from the rocks of the moun- 
 tains and foothills, spread by streams during the flood season. 
 CROPS: On account of the impossibility of cultivation, adapted only 
 to grazing. 
 
Fine Sandy Loam 149 
 
 COARSE SANDY LOAMS 
 
 The coarse sandy loams as the name implies, carry large amounts 
 of gravel, medium, coarse and fine sands. This gives free movement 
 of air and moisture, makes them warm, and light to cultivate. They 
 are well drained, loose and incoherent when dry, but s light ly_sticky 
 when wet. "s— SS^ 
 
 HANFORD COARSE SANDY LOAM. :\tapped in the Madera area. 
 Buff, micaceous, six feet. SUBSOIL: Gravel. Occurs on low ' '^ 
 along the San Joaquin River. ORIGIN: From river sediment. 
 CROPS: Grain, alfalfa, peaches, grapes, truck. 
 
 MEDIA COARSE SANDY LpAM. Mapped in the Madera area. 
 Dark gray, six to forty-eight inches. SUBSOIL: Granitic rocks. 
 OCCURS on sharply rounded hills. ORIGIN: Residual. CROPS: 
 Grazing, grain. 
 
 OAKDALE COARSE SANDY LOAM. Mapped in the Modesto- 
 Turlock area. Chocolate, reddish or yellowish brown, micaceous, 
 twelve inches. SUBSOIL: Yellow gray sand loam, free from hard- 
 pan. OCCURS: Level land, along rivers. ORIGIN: Alluvial, modi 
 fied by old channel material. CROPS: Strawberries, bramble berries, 
 almonds, olives, citrus, melons, vegetables. Free from alkali. Physical 
 analysis: Fine gravel 13.2, coarse sand 38.8, medium sand 11.1, fine 
 sand 14.0, very fine sand 2.7, silt 14.4, clay 5.2. 
 
 PORTERSVILLE COARSE SANDY LOAM. Mapped in the Por 
 tersville area. Black, micaceous, one to six feet. SUBSOIL: Granitic 
 rocks. OCCURS on lower slopes of the foothills. ORIGIN: Residual 
 from the underlying granite, more or less modified by alluvial wash. 
 CROPS: Grain; adapted to citrus and deciduous fruits under irrigation. 
 PHYSICAL ANALYSIS: Fine gravel 6.4, coarse sand 20.0, medium 
 sand 10.3, fine sand 21.5, very fine sand 9.4, silt 22.3, clay 9.9. 
 
 LOAMY COARSE SAND 
 
 In these soils the very fine sand predominates giving the soil a 
 loamy character. 
 
 FRESNO LOAMY COARSE SAND, flapped in the Madera area. 
 Brown to gray, one to six feet. SUBSOIL: Bluish hardpan. OCCURS 
 on lower plains, and in swampy ground. ORIGIN: From former and 
 present sloughs, modified by surface erosion. Drainage poor. CROPS: 
 Alfalfa, grapes, adapted to peaches, figs, olives, and small fruit where 
 it can be drained. PHYSICAL ANALYSIS: Fine gravel 8.1. coarse 
 sand 22.3, medium sand 12.7, fine sand 21.7, very fine sand 25.8, silt 5.6. 
 clay 3.8. 
 
 COARSE SAND 
 
 Fine Coarse Medium Fine Very fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Fresno 12.0 29.7 18.4 23.6 8.8 4.3 3.1 
 
 Hanford 10.0 28.7 16.4 19.6 8.2 12.2 4.8 
 
 Madera 10.7 25.6 15.3 21.1 12.8 6.9 7.6 
 
 Average 10.9 28.0 16.7 21.4 6.6 7.8 5.1 
 
150 Soils of California 
 
 FRESNO COARSE SAND. Mapped in the Madera area. Gray to 
 yellow gray, six feet. SUBSOIL: Brown sand. OCCURS on valley 
 plain, marked by old water courses. ORIGIN: Alluvial. CROPS: 
 Adapted to peaches, vines, alfalfa. 
 
 HANFORD COARSE SAND. Mapped in the Madera area. Brown 
 to gray brown, micaceous, six feet. SUBSOIL: Same or finer material. 
 OCCURS: Along old river channels. ORIGIN: Alluvial, from flood 
 of present streams. CROPS: Adapted to alfalfa. 
 
 MADERA COARSE SAND. Mapped in the Madera area. Brown, 
 micaceous, four to six feet. SUBSOIL: Red hardpan. OCCURS: As 
 narrow bodies following the meandering of streams, as knolls and 
 ridges between streams. ORIGIN: Reworking of the original hardpan. 
 CROP: Grain. 
 
CHAPTER XX 
 
 FINE SANDS 
 
 RIVER WASH AND ROCK OUTCROP. ROUGH 
 
 STONY LAND. PEAT. MUCK. LAKE AND 
 
 MARSH. MEADOW SAND. DUNE SAND. 
 
 Fine Coarse Medium Fine Very fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Fresno 1.5 8.5 8.2 37.3 22.0 17.6 5.5 
 
 Hanford 0.0 1.2 4.8 33.3 32.1 21.3 3.8 
 
 Indio 0.1 0.5 2.8 27.7 51.3 13.7 3.1 
 
 Sacramento 0.1 1.0 2.9 59.1 20.6 14.0 2.9 
 
 Highest 1.5 8.5 8.2 59.1 51.3 21.3 5.5 
 
 Lowest 0.0 0.5 2.8 27.7 20.6 13.7 2.9 
 
 Average 0.4 2.8 4.7 39.3 31.5 16.4 3.8 
 
 Soils that contain less than twenty per cent of silt and clay are 
 called fine sand, if they contain more than fifty per cent of fine sands, 
 or less than twenty-five per cent of fine gravel, coarse and medium 
 sand. These soils are generally micaceous, light, smooth, open, porous, 
 friable, incoherent and well drained, unless the water table is locally 
 high. They are not retentive of moisture, and are easily cultivated. 
 FRESNO FINE SAND. Mapped in the Modesto-Turlock and Stock- 
 ton areas. That mapped as Fresno fine sand in the Los Angeles and 
 Bakersfield areas has been reclassified as Hanford fine sand. That 
 mapped as Fresno fine sand in the Indio area has been reclassified as 
 Indio fine sandy loam. That classified as Fresno fine sand in the Sac- 
 ramento area has been reclassified as Hanford fine sandy loam. Light 
 yellow, light brown, gray brown, three to six feet. SUBSOIL: Similar, 
 heavier, tenacious when wet. OCCURS: In long narrow areas, gen- 
 erally level. ORIGIN: Micaceous granitic material predominates. 
 CROPS: When irrigated, adapted to alfalfa, forage, hard fruits, vines, 
 etc., requiring a loose, well drained soil. The alkali in the subsoil is 
 not injurious when the land is well drained. 
 
 HANFORD FINE SAND. Mapped in the Hanford, Lower Salinas 
 Valley and Madera areas. Mapped as Fresno fine sand in the Bakers- 
 field and Los Angeles areas. Yellowish, well drained, three to six feet. 
 SUBSOIL: Fine sand, loam, sandy loam. OCCURS: On delta plains, 
 slightly elevated ridges, lower valley floors, river terraces, along for- 
 mer stream channels, level, in irregular shaped bodies. ORIGIN: 
 Sedimentary deposits, originally derived from the disintegration of 
 granitic rocks, deposited by local streams, carried by currents of mod- 
 erate velocity and deposited in slack waters. CROPS: Truck, alfalfa, 
 fruit. Some alkali in the surface foot where the land has not been 
 cultivated or irrigated. 
 
152 Soils of Califobnia 
 
 INDIO FINE SAND. Mapped as Fresno sandy loam in the Indio 
 area. Grayish, poorly drained, high water table, three to six feet. 
 SUBSOIL: Coarse sand. OCCURS: On the slopes below the Indio 
 sand, full of blowouts, small dunes, and shallow depressions. ORIGIN: 
 Derived from the wash from the mountains and deposited under the 
 waters of the basin when it was an arm of the sea. CROPS: Where it 
 is not too alkaline will produce any crops adapted to the climate. 
 ORLAND FINE SAND. Mapped in the Colusa area. Dark drab, six- 
 inches to three feet. SUBSOIL: River sands and gravel. OCCURS: 
 In small bodies in bottom lands, a little above stream channels. 
 ORIGIN: Recent stream deposits. CROPS: Dry farming, grain, hay, 
 pasture. Generally free from alkali. Not analyzed. 
 SACRAMENTO FINE SAND. Mapped in the Marysville and Wood- 
 land areas. Brown, yellow, buff, variable in texture, six to eighteen 
 inches. SUBSOIL: Silty, loamy or coarser sand material. OCCURS: 
 On higher elevations approaching the river. ORIGIN: Alluvial. 
 CROPS: Garden truck, small fruits. 
 
 SAND 
 
 Fine Coarse Medium Fine Very fine 
 
 gravel sand sand sand sand Silt Clay 
 
 Fresno 2.1 16.8 22.0 25.8 18.7 11.1 ^.0 
 
 Hanford 5.1 14.6 15.5 32.5 16.6 7.9 3.7 
 
 Imperial 0.0 18.0 21.9 34.1 24.1 0.2 1.7 
 
 Madera 1.5 21.4 25.7 27.6 9.5 9.4 4.2 
 
 Maricopa 2.4 13.5 26.6 33.9 15.8 4.9 2.8 
 
 Oakdale 0.0 11.3 25.8 45.5 5.3 8.9 2.2 
 
 Oxnard 0.7 8.6 22.5 32.4 16.2 11.3 6.2 
 
 Sacramento 0.0 3.1 30.5 60.0 2.3 2.2 1.0 
 
 San Joaquin 3.6 15.6 23.3 27.9 12.3 8.9 4.8 
 
 Santa Clara 0.0 3.7 22.0 58.0 5.1 4.8 7.0 
 
 Highest 5.1 21.4 30.5 60.0 24.1 11.3 7.0 
 
 Lowest 0.0 3.1 15.5 25.8 2.3 0.2 1.0 
 
 Average 1.5 12.7 23.6 37.8 12.6 7.6 3.7 
 
 The sand soils in the arid regions are as rich as the other soils, 
 and when irrigated are recognized as one of the most important soil 
 types of the west. They are leachy if the soil grain is large. The finer 
 the sand the more valuable the soil as a rule. They are quickly parched 
 in dry weather, absorbing little if any moisture from the air. They dry 
 out quickly after rain, or irrigation, and can be worked quickly. Thcj' 
 are warm and hold heat well, and are best adapted to quick growing 
 crops. Soils that contain less than twenty per cent of silt and clay are 
 called sand, if they contain more than twenty-five per cent of fine 
 gravel and medium sand, and less than fifty per cent of fine sand. 
 They vary from fine to medium texture, and are generally micaceous 
 and smooth. Light, open, loose, or only slightly coherent, they are 
 very porous and friable. They are not retentive of moisture, generally 
 well drained and are easily culutivated, as they never clod or bake, 
 and there is no danger of puddling. 
 
 FRESNO SAND. Mapped in the Fresno, Hanford. Madera, Modesto- 
 Turlock, and Stockton areas. That mapped as Fresno sand in the 
 Bakersfield, Sacramento, San Bernardino, San Gabriel, and Santa .Ana 
 
Fine Sands 153 
 
 areas has been reclassified as Hanford sand. That mapped as Fresno 
 sand in the Indio area has been reclassified as Indio sand. White, gray, 
 brown, six feet. SUBSOIL: White sandy loam. OCCURS; In strips, 
 on uniform sloping plains, in dune-like ridges. ORIGIN: From I he 
 "White formation," consisting of interstratified sands, sandy loams, 
 and volcanic ash deposits. CROPS: Wherever well drained, peaches, 
 grapes, almonds, nectarines, apricots, cherries, olives, alfalfa, sweet 
 potatoes, cantaloupes, berries, early truck. Free from harmful quan- 
 tities of alkali, and when well drained none need rise from the subsoil. 
 HANFORD SAND. Mapped in the Portersville area. Mapped as 
 Fresno sand in the Bakersfield, Los Angeles, Lower Salinas Valley, 
 Sacramento, San Bernardino, San Gabriel, and Santa Ana areas. Light 
 gray to brown, slightly yellowish, medium to coarse, four to twenty 
 feet. SUBSOIL: Sand, gravel, local hardpan. OCCURS: On lower 
 terraces, level plains, gentle slopes, lower edge of mountain aprons, 
 along streams, in slightly depressed areas representing former streams, 
 in strips, smooth, level, locally slightly wind-blown. ORIGIN: Recent 
 sedimentary deposits, from original granitic material, deposited by 
 shifting currents and flood waters of adjacent and former streams. 
 CROPS: Adapted to any crop suited to the local climatic conditions; 
 to fruits that require well drained soils that can be irrigated during the 
 dry season. Planted to truck crops, grains, alfalfa, deciduous fruits, 
 raisin grapes, potatoes in the north, wine grapes, peaches, citrons, 
 apricots, in the south; the walnut groves of Rivera, Anaheim, Fuller- 
 ton, Elmonte and Santa Ana; the oranges and lemons of Covina, and 
 Santa Ana; celery of Santa Ana, etc. Generally free from alkali, a few 
 spots the exception. 
 
 IMPERIAL SAND. Mapped in the Imperial area. Mapped as Gila 
 fine sand, Yuma area. Fine to coarse, organic matter small per cent. 
 SUBSOIL: Loam, clay loam, sandy clay, clay. OCCURS: Smooth, 
 level, near sandunes. ORIGIN: Same material as sandunes. CROPS: 
 One of the best soils in Imperial Valley, suitable for any crops adapted 
 to the climate. Practically free from alkali except where underlaid by 
 heavy subsoil. 
 
 INDIO SAND. Mapped as Fresno sand in the Indio area. Whitisli 
 gray, six feet. SUBSOIL: Same but coarser. OCCURS: Skirting the 
 mountains, above present water supply. ORIGIN: Old beach sand 
 with material washed down from the mountain. CROPS: Would make 
 good soil for fruits, grains and alfalfa. Free from alkali. Not analyzed. 
 GRAVELLY PHASE: Grayish white, coarse hard material, six feet or 
 more, above the old beach line, alluvial fans and cone deltas, caused by 
 storm waters. 
 
 MADERA SAND. Mapped in the Madera area. Brown, three to six 
 feet. SUBSOIL: Red hardpan. OCCURS in long narrow bodies 
 parallel to shallow water courses on rolling land, marked by hog- 
 wallows. ORIGIN: Doubtful — possibly from blowing out of material 
 from dry stream courses. CROP: Grain; adapted to alfalfa, grapes, 
 figs, olives, stone fruits. 
 
 MARICOPA SAND. Mapped as Fresno sand, gravelly phase, in the 
 Ventura area. Light brown to white, gravelly, six feet. SUBSOIL: 
 Variable. OCCURS: As long, gentle sloping valleys, floor of small 
 
154 Soils of California 
 
 washes, next terrace above bottom lands, smooth to steep sloping. 
 ORIGIN: Coarsest wash from the hills, by small streams and heavy 
 downpours. CROPS: Fruits suited to the climate, lima beans. Free 
 from alkali. 
 
 OAKDALE SAND. Mapped in the Modesto-Turlock area. Light 
 brown, micaceous, carries silt and clay, six feet. SUBSOIL: Same, 
 heavier. OCCLTRS: Along the lower slopes of terraces, smooth, gently 
 sloping. ORIGIN: Working over of the Oakdale coarse sandy loam 
 by the wind, the finer particles collecting along the lower sides of the 
 terraces. CROPS: Almonds; adapted to many crops where irrigated. 
 OXNARD SAND. Mapped in the Los Angeles, San Bernardino and 
 Ventura areas. Gray to yellowish gray, dark gray, gray brown; may 
 grade into indurated sand; number of local phases; six to ten feet. 
 SUBSOIL: Same. OCCURS: At the edge of mesas, rolling, undulat- 
 ing, in ridges or as dunes, wind-blown, in hills, on deltas. ORIGIN: 
 Blown out of the adjacent soils, largely aeolian, beach sand driven 
 inland. CROPS: Olives, grains, corn, barley, peas, sugar beets, grapes, 
 citrus fruits, berries, truck, flowers. Free from alkali. 
 PAJARO SAND. Mapped in the Pajaro area. Light brown, six 
 feet. SUBSOIL: Same, heavier. OCCURS: At the junction of streams 
 by a rapid rush of large bodies of water. ORIGIN: Alluvial and sedi- 
 mentary. CROPS: Fruits, vegetables and grains, when not too wet. 
 Not analyzed. 
 
 SACRAMENTO SAND. Mapped in the Red Bluff and Woodland 
 areas. Light to dark gray, two to four feet. SUBSOII>: Sand heavier 
 texture. OCCURS: Ridges and mounds subject to overflow. ORIGIN: 
 Wash from the rivers deposited by rapidly moving waters. CROPS: 
 Requires leveling, and protection from floods before using for truck- 
 crops. 
 
 SAN JOAQUIN SAND. Mapped as Fresno sand in the Fresno area. 
 Mapped as Fresno red sand, Sacramento area. Gray to dark brown, 
 six feet. SUBSOIL: Red sandy loam, red sandy adobe, red sandy 
 hardpan. OCCURS in irregular shaped bodies, summits of higher 
 ridges, undulations and upper valley margins. ORIGIN: From adja- 
 cent granitic rocks, intermingled with the wash from diabase, amphib- 
 olite and volcanic rocks, ancient Pleistocene lake deposits, weathering 
 nf red sandstone formation. CROPS: One of the most important soils 
 of the Sacramento area; citrus and stone fruits, figs, peaches, plums, 
 prunes, cherries, apricots, olives, nectarines, raisin grapes. Alkali 
 not present in harmful quantities. 
 
 SANTA CRUZ SAND. Mapped in the Pajaro area. Light to dark 
 red, reddish brown, three to six feet. SUBSOIL: Disintegrated red 
 sandstone. OCCURS: Occupies spurs of the mountains. ORIGIN: 
 Weathering of red sandstone in place. CROPS: Oats and Indian 
 corn, eucalyptus trees. 
 
 DUNESAND. Mapped in the Indio, Imperial. Los Angeles, Pajaro, 
 and Ventura areas. Also called coastal sand, beach sand, etc. The 
 name "dune" is given to the rounded hills and ridges of wind-blown 
 sand common in arid regions and along windy shores. They are nat- 
 
Fine Sands 155 
 
 urally of moderately fine and uniformly assorted materials as shown 
 by an analysis: Fine gravel 0.0, coarse sand 24.7, medium sand 46.3, 
 fine sand 25.2, very fine sand 0.8, silt 1.7, and clay 1.6. They are usually 
 considered undesirable for agricultural purposes, but they are not infer- 
 tile in the sense that they lack the mineral elements of plant food, as 
 they contain the ordinary soil minerals and wherever reclaimed have 
 proven perfectly capable of supporting agriculturally valuable vegeta- 
 tion. The barrenness of the dunesand is due to lack of water and 
 instability of surface rather than to any deficiency of mineral plant 
 nutrients. Although very absorptive, these sands have very little 
 power to retain moisture, and it is generally too expensive to level 
 them for irrigating. They are free from alkali or contain only harm- 
 less amounts. They are well drained and have a texture favorable for 
 cultivation. Many of the choice orchards of Southern California were 
 considered a couple of decades ago as worthless sandhills, and now 
 serve to show what many so-called dune wastes could become if prop- 
 erly handled. The first step is stopping the sand movement and estab- 
 lishing a stable and permanent surface. This is done by planting 
 grasses which will bind the surface and protect it from attack by the 
 wind. Marram or beach grass (Ammophila areparia) has been found 
 particularly useful on coastal dunes. Many reclaimed areas are then 
 put into forest. The reclamation work at Golden Gate Park, San 
 Francisco, shows what may be accomplished with these sands. 
 
 RIVERWASH AND ROCK OUTCROP. Mapped in the Colusa. 
 Red Bluff, Redding, Livermore, San Bernardino, Bakersfield, Modesto- 
 Turlock, Madera, Sacramento, Los Angeles, Portersville, San Jose, San 
 Gabriel, Ventura, Lower Salinas Valley, Fresno, and Woodland areas. 
 SOIL: Consists of a mixture of rounded and flattened gravel, cobble- 
 stones, sand and finer sediments, the coarser material greatly predom- 
 inating, merges into adjacent fine sands and gravelly loams, leachy 
 character, six inches to six feet. OCCURS: Occupies beds of portions 
 of the flood plains, lower terraces, abandoned and present creek and 
 river channels, subject to overflow, low flat sandbars and spits. 
 ORIGIN: Recent alluvial, from a great variety of rocks, CROPS: 
 Generally barren and of no value except for grazing. 
 ROUGH STONY LAND. Mapped in the Colusa. Redding, Porters- 
 ville, Sacramento and Yuma-California areas. SOIL: Light red. graj'. 
 drab, yellow red, loam or clay loam, friable, carries relatively large 
 amount of cobbles, small boulders and gravel, six inches to six feet, 
 from bare rock outcrops to sand. SUBSOIL: Yellow, red, clays, 
 indurated clay hardpan. volcanic ash, breccias. OCCURS: In narrow 
 elongated bodies, bordering stream valleys, higher hilly portions or 
 knolls of uplands, rugged hills. ORIGIN: From ancient alluvial 
 deposits, from volcanic muds and breccias, residues. CROPS: Grazing. 
 PEAT. Mapped in the Los Angeles, San Bernardino, Santa Ana and 
 Stockton areas. Dark brown to black; smooth, pasty consistency when 
 wet, depth variable, no tendency to puddle, friable, easily cultivated 
 when once broken, light weight, poorly drained. SUBSOIL: Sand, 
 silts, or sandy clay. OCCUR at river deltas, shallow fresh water lakes, 
 former lake beds, near springs. ORIGIN: Formed by the decay of 
 
156 Soils of Califobnia 
 
 vegetation in shallow lakes, ponds, or swamps; some clay and silt arc 
 blown in by the winds or carried in by streams; they contain from 
 thirty to ninety per cent of humus; from aquatic plants in various 
 stages of decomposition, fine alluvial river or tidal silt intimately 
 mixed with partially decayed vegetation, plant routs, stems, and fibres 
 in great profusion, or vegetable matter grown and more or less pre- 
 served in standing water, growing and decaying tules. CROPS: If the 
 vegetable matter is sufficiently decayed and mingled with some minertl 
 matter, and the soil is well drained, they yield enormously under favor- 
 able conditions, but successive croppings decrease production. Aspara- 
 gus, beans, celery, onions, timothy, redtop, rye grass, clover, grains, 
 corn, potatoes. Naturally free from alkali. 
 
 MUCK. Muck soils represent the advanced state of change in peat 
 areas. They are of limited extent and poorly drained. They are highly 
 valued for their adaptation to special crops, such as celery, onions, 
 peppermint, etc. 
 
 LAKE AND MARSH SOILS. Mapped in the Bntte Lake area. 
 Formed in shallow lakes such as favor the growth of aquatic plants, 
 as the tules (Scirpus) and cat-tails (Typha) which form great masses 
 of decaying matter, giving to the loamy and sandy soils a friable mucky 
 or peaty character. When properly drained they are extremely fertile 
 and produce immense crops of timothy, clover, red top, potatoes, cel- 
 ery, asparagus, etc. 
 
 MEADOW SOIL. Mapped in the Fresno area. Fine gravel 0.0, 
 coarse sand 0.3. medium sand 1.9, fine sand 10.1, very fine sand 45.9, 
 silt 31.5, clay 5.3. These soils consist mainly of very fine sand and silt 
 with a little clay. They are fine micaceous sandy loams with little true 
 clayey matter, and very little coarse sand or gravel, variable in texture, 
 color and depth. OCCUR: They comprise lowlying, flat, and poorly 
 drained land of variable texture, on the "Meadows" along Kings River, 
 along river bottoms. ORIGIN: Sediments dropped by rivers in flood, 
 in part material cut from the banks, sorted over, and laid down. 
 CROPS: Much of it can be reclaimed by draining, and it is then 
 adapted to a variety of crops, pasture, truck, orchards, corn. Alkali is 
 occasionally found in a few spots. 
 
CHAPTER XXI 
 HARDPAN. ALKALI. 
 
 Hardpan in the true sense of the word is not bedrock, nor a 
 material formed under the water as sedimentary rocks are formed, but 
 is a secondary product formed in the soil through local conditions. All 
 water which percolates through the soil soon dissolves from it soluble 
 materials of dift'erent kinds. A change of temperature, a checking of 
 the water movement, or a rapid loss of the contained gases, or other 
 causes may precipitate hardpan near the zone of change. It is impene- 
 trable to plant roots and limits the root zone of crops; cultivation is 
 interrupted, movement of the soil water is arrested, drainage retarded, 
 and the power to retain and to deliver water is decreased. Hardpan is 
 subject to much variation, even in short distances. It may be exposed 
 on the surface where the soil has been subject to erosion, or it may 
 occur at any depth below the surface. Where it is thin, easily disin- 
 tegrated, low in alkali contents, and easily penetrated by plant roots, it 
 is not harmful and may even be beneficial in holding the moisture 
 within reach of the plants. 
 
 Where it occurs near the surface or where it is very hard it is 
 harmful in several ways. It prevents the deep penetration necessary 
 for trees, vines and alfalfa. It restricts drainage, often forming shal- 
 low basins of water-saturated soil fatal to plant roots. The excess of 
 lime occurring in hardpan is especially injurious to citrus fruits, as 
 indicated by the yellowing of the leaves. Indications of hardpan are 
 usually seen in hummocky, uneven surface, and small shallow depres- 
 sions, the result of deficient drainage. When the hardpan is three or 
 four feet below the surface the land may be adapted to vines and other 
 shallow rooted growths. Trees require deep soils and hardpan must 
 be broken up by blasting where the trees are to be planted. 
 
 ALKALI SOILS 
 
 Lands may carry alkali salts in sufficient quantities to become more 
 or less a menace to irrigated crops. These salts are sodium chloride, 
 magnesium chloride, calcium chloride, sodium sulfate, magnesium 
 sulfate, calcium sulfate, and sodium carbonate. When sodium carbon- 
 ate is present, the salt mixture is commonly known as "black alkali," 
 because the charring effect of this salt upon organic matter gives a 
 characteristic black color to the soil. When sodium carbonate is 
 absent, the salts effloresce on the surface as a white powder, or crust, 
 called "white alkali." The white alkali is not so injurious to crops, and 
 is much more soluble than the black alkali. The greater part of the 
 alkalies originate from alkali-bearing shales and other sedimentary 
 rocks, especially from those of marine origin. Alkali is confined 
 chiefly to the heavier soil types, and normally is more apt to be dis- 
 tributed through the subsoils. There is no evidence that there are 
 deep seated accumulations of alkali. 
 
158 Soils of California 
 
 CLASSIFICATION OF ALKALI SOILS. The percent of alkali in 
 the soils is determined in the field when the soil maps are made by 
 means of the electric resistance of the soil solution, each foot section 
 being determined separately, and are also determined volumetrically 
 in the field from the total of soluble salts. 
 
 The alkali contents of the soils are graded according to the aver- 
 age salt contents to the depth of six feet, as follows: 
 
 No. 1 0. to 0.20 per cent 
 
 " 2 0.20 to 0.40 per cent 
 
 " 3 0.40 to 0.60 per cent 
 
 " 4 0.60 to 1.00 per cent 
 
 " 5 1.00 to 3.00 per cent 
 
 LIMITS OF ENDURANCE. A number of factors enter into the 
 
 limit of endurance of plants for alkali. With the same amount of alkali, 
 plants will suffer less in heavier soils than in sandy. Crops will stand 
 more alkali with thorough cultivation, and they will stand a consider- 
 able amount of alkali if they are started under favorable conditions. 
 In some districts sugar beets do well on soils containing a large amount 
 of alkali. They are planted when the ground is wet by rains, or irri- 
 gation, which carries the alkali into the depths of the soil. When the 
 soil dries out the alkali is brought to the surface and is left above 
 the area of the active roots. Where the average alkali content is less 
 than 0.20 per cent, no injury to crops may be feared under general 
 conditions. This is, however, considered the minimum limit of dan- 
 ger for ordinary irrigated crops. Many crops can be successfully 
 grown where the average concentration is from 0.20 to 0.40 per cent, 
 but lands ranging from 0.40 to 0.60 per cent are generally devoted to 
 pasture. Over 0.40 by no means takes away the value of the land for 
 some agricultural purposes. Some of the hardier fruits, especially 
 pears, can be grown under intelligent cultivation. Onions, asparagus, 
 and sugar beets, barley, grain or hay, will resist this per cent if the 
 ground is well prepared for the seed bed and the salts kept away from 
 the tender young roots by frequent irrigation and cultivation. Sorg- 
 hum, sugar beets and alfalfa have produced partial to full crops on land 
 ranging from 0.40 to 0.60. With black alkali, 0.05 is the minimum of 
 concentration beyond which crops begin to suffer. 
 
 Some alkali salts are readily carried into solution and their dis- 
 tribution in the soil is determined largely by the movements of soil 
 waters. The concentration in lower valley plains and depressions of 
 deficient drainage has been caused mainly by evaporation from flood 
 waters charged with small quantities of alkali salts leached from the 
 higher adjacent soil bodies and from alkali-bearing rocks. Rapid 
 evaporation, long periods of hot dry weather, compact, uncultivated 
 and unshaded soil surfaces, with water table near the surface tend 
 towards concentration of alkali at or near the surface. While the con- 
 centration and distribution of alkali in the soil and subsoil depends 
 upon a variety of circumstances, it will be found that the main ones 
 are — soil texture and structure, position of the underground water 
 table, and the rapidity, direction and movement of the soil waters. 
 Where soils are subject to overflow and have a high water table there 
 is an accumulation of salts at the intervals between floods. Each over- 
 
Habdpan. Alkali 159 
 
 flow washes the salts out and leaves the soil temporarily free from the 
 salts at the surface. These lands are called "intermittent alkali lands." 
 The alkali salts are readily dissolved and carried downward and out- 
 ward in soils of loose, open texture and structure, by water applied 
 in excess of saturation. In soils of fine texture and compact structure 
 the salts tend to cling to the finer particles, checking the downward 
 movement, hence salts tend to collect near the surface and within the 
 root zone of crops. Heavy rains, as well as surface irrigation, soaking 
 downward into the soil dissolve and carry the salts downward by grav- 
 ity to the limits of penetration. If the surface flooding be copious and 
 gravitation movement aided by natural or artificial underdrainage, 
 large amounts of the alkali may be permanently removed. As soon as 
 the downward movement of flood waters ceases, an upward movement 
 begins through capillary action caused by the surface evaporation, 
 causing a surface crust of alkali as the waters evaporate. The surface 
 should be kept, between the periods of flooding, in a condition of fine 
 tilth by cultivation, the mulch of loose earth retarding evaporation and 
 the upward movement by capillarity. As soon as the soil is free from 
 excess, by underdrainage and occasional flooding, thorough cultivation 
 should begin, using alkali-resisting crops which can be cultivated fre- 
 quently or which shade the surface, as sorghum, sugar beets or alfalfa. 
 In the case of black alkali, the application of gypsum to the surface is 
 beneficial, changing the sodium carbonate into the more soluble sodium 
 sulfate. 
 
APPENDIX 
 
 CHANGED SOIL NAMES 
 
 The following list gives the soil names in published reports 
 of the U. S. Bureau of Soils that as a result of correlation have 
 been changed or dropped. In the first column is given the name 
 at present used, in the second column is given the original name. 
 
 Present Name Name as published 
 
 BAKERSFIELD AREA 
 
 Hanf ord sand Fresno sand 
 
 Hanf ord fine sand Fresno fine sand 
 
 Hanford fine sandy loam Fresno fine sandy loam 
 
 Fresno loam Maricopa loam 
 
 Placentia sandy adobe Maricopa sandy adobe 
 
 Hanford clay loam Oxnard silt loam 
 
 Placentia sandy loam Placentia sandy loam 
 
 Riverwasli Riverwash 
 
 Gravelly areas Gravelly areas 
 
 COLUSA AREA 
 (No changes in Colusa area yet.) 
 
 Norman clay adobe 
 
 Orland fine sandy loam. 
 
 Orland fine sand. 
 
 Riverwash. 
 
 Rough stony lands. 
 
 Sacramento gravelly sandy loam. 
 
 Sacramento fine sandy loam. 
 
 Sacramento loam. 
 
 Sacramento silt loam. 
 
 Sacramento silty clay loam. 
 
 Sacramento silty clay. 
 
 San Joaquin gravelly loam. 
 
 San Joaquin loam. 
 
 Sites sandy loam. 
 
 Sites loam. 
 
 Sites clay loam adobe. 
 
 Willows loam. 
 
 Willows silty clay loam. 
 
 Willows clay loam. 
 
 Willows clay. 
 
 Willows clay adobe. 
 
 FRESNO AREA 
 
 Stockton fine sandy loam Fancher sandy loam 
 
 San Joaquin sand Fresno red sand 
 
 Fresno fine sandy loam Fresno sandy loam 
 
 San Joaquin sandy loam San Joaquin red adobe 
 
 San Joaquin sandy loam San Joaquin sandy loam 
 
 Stockton clay loam adobe San Joaquin black adobe 
 
 Placentia clay loam adobe Sierra adobe 
 
 Riverwash Riverwash 
 
 Meadow Meadow 
 
Changed Soil Names 161 
 
 Present Name Name as published 
 
 HANFORD AREA 
 
 Hanford sandy loam Fancher sandy loam 
 
 Fresno sand Fresno sand 
 
 Fresno sandy loam Fresno sandy loam 
 
 Hanford fine sand Hanford fine sand 
 
 Hanford fine sandy loam Hanford fine sandy loam 
 
 Stockton clay loam adobe San Joaquin black adobe 
 
 IMPERIAL AREA 
 
 Gi'a fina sandy loam Gila fine sandy loam 
 
 Dunesand Dunesand 
 
 Imperial sand Imperial sand 
 
 Imperial sandy loam Imperial sandy loam 
 
 Gila loam Imperial fine sandy loam 
 
 Indio gravelly loam Imperial gravelly loam 
 
 Imperial clay loam Imperial loam 
 
 Imperial clay Imperial clay 
 
 Gila silt loam Imperial silt loam 
 
 INDIO AREA 
 
 Dunesand Dunesand 
 
 Tndio sand Fresno sand 
 
 Indio fine sandy loam Fresno fine sandy loam 
 
 Indio fine sand Fresno sandy loam 
 
 Imperial clay Imperial clay 
 
 LOS ANGELES AREA 
 
 Hanford fine sand Fresno fine sand 
 
 Hanford fine sandy loam Fresno fine sandy loam 
 
 Placentia loam adobe Fullerton sandy adobe 
 
 Hanford sand Fresno sand 
 
 Galveston clay Galveston clay 
 
 Placentia loam Los Angeles sandy loam 
 
 Maricopa fine sandy loam Maricopa gravelly loam 
 
 Maricopa sandy loam Maricopa sandy loam 
 
 Oxnard sand Oxnard sand 
 
 Oxnard clay loam Oxnard loam 
 
 Peat . t Peat 
 
 Placentia fine sandy loam Placentia sandy loam 
 
 Hanford loam Santiago silt loam 
 
 Hanford clay loam Santiago silt loam 
 
 Oxnard clay loam adobe San Joaquin black adobe 
 
 Sierra sandy adobe Sierra adobe 
 
 Rlverwash Riverwash 
 
 REDDING AREA 
 (No changes in the Redding area.) 
 Anderson gravelly loam. 
 Anderson fine sandy loam. 
 Bellavlsta sandy loam. 
 Redding gravelly loam. 
 
 Redding loam. ' 
 
 Riverwash. 
 Rough stony land. 
 Sacramento gravelly sandy loam. 
 Sacramento fine sandy loam. 
 Sacramento loam. 
 Sacramento silt loam. 
 
 SACRAMENTO AREA 
 
 Hanford sand Fresno sand 
 
 Hanford fine sandy loam Fresno fine sand 
 
 Hanford gravel Fresno gravel 
 
 San Joaquin sand Fresno red sand 
 
 Riverwash Riverwash 
 
 Rock outcrop Rock outcrop 
 
 Rough stony land Rough stony land 
 
162 Soils of Caui-ornia 
 
 Present Name Name as published 
 
 Hanford silt loam Sacramento silt loam 
 
 Hanford clay adobe Salinas gray adobe 
 
 San Joaquin sandy loam San Joaquin sandy loam 
 
 ban Joaquin fine sandy loam San Joaquin fine sandy loam 
 
 San Joaquin clay loam adobe San Joaquin red adobe 
 
 Sheridan sandy loam Sheridan sandy loam 
 
 blerra stony loam Sierra stony loam 
 
 Sierra sandy loam Sierra sandy loam 
 
 Sierra loam adobe Sierra loam 
 
 Sierra clay loam Sierra clay loam 
 
 SALINAS AREA 
 
 Maricopa gravelly loam Arroyo seco sandv loam 
 
 Hanford fine sandy loam Fresno fine sandy loam 
 
 Hanford sand Fresno sand 
 
 Hanford fine sand Hanford fine sand 
 
 Placentia fine sandy loam Placentia sandy loam 
 
 Riverwash Riverwash 
 
 Salinas gray adobe Salinas gray adobe 
 
 Oxnard gravelly loam Salinas shale loam 
 
 Hanford silt loam Santiago silt loam 
 
 Hanford clay loam Santiago silt loam 
 
 Oxnard clay loam adobe San Joaquin black adobe 
 
 Maricopa gravelly .sand Soledad gravelly sand 
 
 SAN BERNARDINO AREA 
 
 Hanford fine sandy loam Fresno fine sandy loam 
 
 Placentia sandy adobe Fullerton sandy adobe 
 
 Hanford sand Fresno sand 
 
 Maricopa gravelly sand Maricopa gravelly sand 
 
 Maricopa loam Maricopa sandy loam 
 
 Oxnard sand Oxnard sand 
 
 Oxnard .sandy loam Oxnard sandy loam 
 
 Oxnard fine sandy loam Oxnard fine sandy loam 
 
 Oxnard loam Oxnard loam 
 
 Peat Peat 
 
 Placentia fine sandy loam Placentia sandy loam 
 
 Placentia clay loam Placentia loam 
 
 Placentia coarse sandy loam Placentia coarse sandy loam 
 
 Riverwash Riverwash 
 
 Salinas gray adolie Salinas gray adobe 
 
 Hanford clay loam Santiago silt loam 
 
 Maricopa sandy loam San Gabriel sandy loatn 
 
 Maricopa gravelly loam San Gabriel gravelly loam 
 
 Maricopa gravelly sand San Gabriel gravelly sand 
 
 Oxnard clay loam adobe San Joaquin black adobe 
 
 SAN GABRIEL AREA 
 
 Hanford sand Fresno sand 
 
 Hanford fine sandy loam Fresno fine sandy loam 
 
 Placentia fine sandy loam Placentia sandy loam 
 
 Riverwash Riverwash 
 
 Hanford clay loam Santiago silt loam 
 
 Maricopa gravelly loam San Gabriel gravelly loam 
 
 San Gabriel gravelly sand San Gabriel gravelly sand 
 
 Oxnard clay loam adobe San Joaquin black adobe 
 
 SAN JOSE AREA 
 
 Maricopa gravelly loam Arroyo Seco sandy loam 
 
 Hanford silt loam Fresno fine sandy loam 
 
 Galveston clay Galveston clay 
 
 Oxnard clay loam Oxnard loam 
 
 Oxnard silt loam Oxnard silt loam 
 
 Placentia fine sandy loam Placentia sandy loam 
 
 Riverwash o •,•.•• • Riverwash 
 
 Salinas gray adobe • • • • • -Salinas gray adobe 
 
 Stockton clay loam adobe San Joaquin black adobe 
 
Changed Soil Names 168 
 
 Present Name Name as published 
 
 SANTA ANA AREA 
 
 Hanf ord sand Fresno sand 
 
 Hanford fine sandy loam Fresno fine sandy loam 
 
 Palcentia loam adobe Fullerton sandy adobe 
 
 Peat Peat 
 
 Placentia fine sandy loam Placentia sandy loam 
 
 Oxnard clay loam adobe San Joaquin black adobe 
 
 Santiago fine sandy loam Santiago sandy loam 
 
 Santiago loam Santiago loam 
 
 Hanford clay loam Santiago silt loam 
 
 SOLEDAD AREA 
 
 Placentia sandy loam Placentia sandy loam 
 
 Fresno sand Fresno sand 
 
 Maricopa gravelly sand Soledad gravelly sand 
 
 Maricopa gravelly loam Arroyo Seco sandy loam 
 
 Oxnard gravelly loam Salinas siiale loam 
 
 Salinas gray adobe Salinas gray adobe 
 
 Rivervsrash Riverwash 
 
 Hanford fine sand Hanford fine sand 
 
 Fresno fine sandy loam Fresno fine sandy loam 
 
 Hanford clay loam Santiago silt loam 
 
 STOCKTON AREA 
 
 Stockton fine sandy loam Fancher sandy loam 
 
 Fresno sand Fresno sand 
 
 Fresno fine sand Fresno fine sand 
 
 Fresno sandy loam Fresno sandy loam 
 
 Fresno fine sandy loam Fresno fine sandy loam 
 
 Peat Peat 
 
 Sacramento clay loam Sacramento clay loam 
 
 San Joaquin sandy loam San Joaquin sandy loam 
 
 San Joaquin loam San Joaquin loam 
 
 Stockton loam Stockton loam 
 
 Stockton loam adobe Stockton loam adobe 
 
 Stockton silt loam Stockton silt loam 
 
 Stockton clay loam adobe Stockton clay loam adobe 
 
 Stockton clay adobe Stockton clay adobe 
 
 VENTURA AREA 
 
 Dunesand Dunesand 
 
 Maricopa sand Fresno sand (gravelly phase) 
 
 Oxnard loam Fresno fine sandy loam 
 
 Placentia sandy adobe Fullerton sandy adobe 
 
 Oxnard sand Oxnard sand 
 
 Oxnard sandy loam Oxnard sandy loam 
 
 Oxnard clay loam Oxnard loam 
 
 Oxnard silt loam Oxnard silt loam 
 
 Placentia loam Placentia sandy loam 
 
 Riverwash Riverwash 
 
 Oxnard gravelly loam Salinas shale loam 
 
 Oxnard clay loam adobe San Joaquin black adobe 
 
 Maricopa gravelly loam San Gabriel gravelly loam 
 
 TUMA-CALIFORNIA AREA 
 
 Maricopa sand Fresno gravelly sand 
 
 Gila fine sandy loam Imperial sandy loam 
 
 Gila loam Imperial fine sandy loam 
 
 Gila silt loam. .Santiago silt loam in 1902 map: changed to Imperial 
 silt loam 1904. 
 
 Gila clay loam Imperial loam 
 
 Rough stony land Rough stony land 
 
 Imperial sand Imperial sand 
 
INDEX 
 
 INDEX TO SOIL NAMES 
 
 COMMON NAMES. 
 
 Acid. soil. 47, 81, 83. 
 Aeolian, 47. 
 Arid. 48, 76. 
 Ashy flat, 47. 
 
 Baybusli pocoson, 4S. 
 Beecli land. 47. 48. 
 Beach sand, 154. 
 Beeswax, 48, 52. 
 Black alkali land, 53. 
 Black gum. 48. 
 Black jack, 48. 
 Black land, 48, 63, 125. 
 Black waxy land, 47. 
 Black post oak, 48. 
 Black prairie, 48. 
 Black walnut, 48. 
 Blue grass, 48. 
 Boggy land, 47. 
 Brier pocoson, 48. 
 Buckleberry, 48. 
 Buckshot. 48. 
 Bugleland, 52. 
 Bullnettle, 48. 
 
 Canebrake, 48. 
 
 Cap. 48. 
 
 Cedar, 49. 
 
 Chaffy, 52. 
 
 Chalk, 48. 
 
 Chestnut. 49. 
 
 Chinquapin. 48. 
 
 Chocolate, 48. 
 
 Clay upland, 47. 
 
 Coarse, 47. 
 
 Coastal sand. 154. 
 
 Cold. 48. 
 
 Conowingo barrens, 49. 
 
 Crawfish. 49, 73. 
 
 Crayfish. 49. 
 
 Cumulose,49. 
 
 Cypress, 49. 
 
 Deadland, 49. 
 Dead, 87. 
 Dilluvial, 49. 
 Drybog, 52, 124. 
 Drybog adobe. 52. 124. 
 Drybog land, 52, 113. 
 Dust, 49. 
 
 Endogenous, 49. 
 Eolian, 47. 
 Exogenous, 49. 
 
 Fine, 49, 63. 
 First bottom land, 49. 
 Flat pine wood, 49. 
 Flat woods, 49. 
 Foothill, 52. 122. 
 
 Galled, 49. 
 Garden, 49. 
 Glacial, 39, 49. 
 Glade, 49. 
 Glady, 50. 
 Granite. 49. 
 Grass peat, 49. 
 Gray, 49. 
 Gray lands, 49. 
 Gray prairie, 49. 
 Gumbo. 50. 
 
 Hardpan, 104. 
 Heavy bottom, 50. 
 Hemlock, 50. 
 Highland, 47. 
 Hogwallow, 60, 110. 
 Hogwallow land, 52. 
 Humus, 60. 
 
 Isinglass, 50. 
 
 Jack pine, 50. 
 
 Lake front, 60. 
 Laterite, 50. 
 Limestone. 47. 50. 
 Limestone land, 50. 
 Loess, 13, 60. 
 Looseland, 60. 
 Lumpy, 71. 
 
 Marine, 50. 
 Marl, 13, 35, 51. 
 Marly peat, 50. 
 Medium peat, 60. 
 Mesquite, 60. 
 Moor earth. 60. 
 Moss peat, 50. 
 Mottled, 51. 
 Mountain. 60. 
 Mulatto. 51. 
 
 Niggerhead, 61. 
 
 Oak, 51. 
 
 Park, 132. 
 Peaty alkali, 51. 
 Peaty loam, 60. 
 Pine flat, 51. 
 
Index to Soil Names 
 
 1«S 
 
 Pine barrens. 51. 
 Pine woods, 61. 
 Plney woods 51. 
 Pipe clay, 51. 
 Pocoson, 48. 
 Post oak flats, 51. 
 Post oak prairie, 51. 
 Post oak swagrs. 61. 
 Prairie, 51. 
 
 Red clay, 47, 51. 
 Redlands. 51, 104. 
 Redwood, 53. 
 Regur, 51. 
 Rich black. 73. 
 Rough pimply, 50. 
 
 Salt marsh, 51. 
 Scrub oak, 51. 
 Sedentary. 51, 96. 
 Shoepeg, 51. 
 Sour, 81. 
 Spouty, 52. 
 Sterile, 51. 
 Stiff, 51. 
 Strong-. 51. 
 Sugar tree, 47. 
 
 Tallow, 52. 
 Tamarack, 52. 
 The barrens, 48. 
 Tidal., 52. 
 Tight, 47, 52. 
 Till, 13, 52. 
 Transported, 52. 
 Tuff. 13, 52. 
 Tule land, 53, 110. 
 
 Vegetables, 52. 
 Vegetable loam, 52. 
 Vegetable muck, 52. 
 
 Wacke, 52. 
 
 Wax, 52. 
 
 Warm, 52. 
 
 Wash, 52. 
 
 White alkali, 53. 
 
 White ash land. 53, 140, 145. 
 
 White clay, 47. 
 
 White gum slash, 50. 
 
 White land, 52. 
 
 White oak, 52. 
 
 Wildgoose land, 53. 
 
 Wornout, 52, 87. 
 
 Yellow prairie, 52. 
 
 SCIENTIFIC NAMES. 
 
 Adobe, 12. 58, 108, 112. 
 Alamo clay adobe, 111. 112. 
 
 " clay loam adobe, 122, 123. 
 Alkali, 83. 157. 
 Alluvial. 94, 100. 
 Altamont clay adobe. Ill, 112. 
 Alvlso clay, 105, 109, 110. 
 Anderson fine sandy loam, 139. 
 161. 
 
 Anderson gravelly loam, 135, 161. 
 Arbuckle clay loam, 117. 
 
 fine sandy loam, 139, 140. 
 " gravelly loam, 135. 
 
 " gravelly sandy loam, 137, 
 
 138. 
 loam, 127, 128. 
 Arnold clay adobe. 111, 112. 
 
 fine sandy ioam, 139, 140. 
 loam. 127, 128. 
 " sandy loam, 144. 
 Arroyo Seco sandy loam, 136, 162, 
 163. 
 
 Bear loam, 127, 128. 
 Bellavista sandy loam, 144, 161. 
 
 • Capay clay, 110. 
 
 clay adobe. Ill, 112. 
 clay loam. 117. 118. 
 Clay, 28, 29, 55, 56, 58, 60, 63, 64, 66, 
 68, 70, 71, 72, 76, 80. 82, 84, 89. 
 90, 96, 107. 109. 
 Clay adobe. 107. 
 Clay_loam, 56, 58. 63. 89. 90. 107. 
 Clay loam adobe. 107. 
 Coarse sand, 55. 56. 58. 66. 71, 89, 107. 
 Coarse sandy loam, 107. 
 Coastal beech, 106. 
 Colluvial, 94, 98. 
 Colluvial and alluvial, 54, 100. 
 Contra Costa sandy loam, 144. 146. 
 Corning gravelly loam. 135. 
 
 loam, 128. 
 Corralltos loam, 127, 128. 
 
 Danville clay loam adobe, 122, 123. 
 Daulton clay adobe, 111. 112. 
 clay loam, 117. 118. 
 " sandy loam. 145. 
 
 Diablo clay adobe. 111. 112. 
 Dublin clay adobe. Ill, 113. 
 clay loam, 117, 118. 
 clay loam adobe. 122, 123. 
 loam. 127. 129. 
 Dunesand. 66, 106. 107. 149, 154, 161. 
 
 163. 
 Dunnlgan clay, 52, 109. 110. 
 
 Elder gravelly fine sandy loam. 137. 
 silt loam. 125. 
 sllty clay loam. 120. 121. 
 Enclnal sandy loam. 97. 144, 145. 
 Esparto clay, 109, 110. 
 
 clay loam, 117. 118. 
 loam. 127. 129. 
 Exeter sandy loam. 144, 145. 
 
 Fancher sandy loam, 143. 145. 160, 
 
 161, 163. 
 Feather loam, 127. 129. 
 
 silt loam, 53. 125. 
 Fine gravel, 55. 
 Fine sand. 55. 63, 71. 89. 107. 
 140. Fine sandy loam. 56, 58, 66, 71, 89, 
 107. 
 
166 Soils of Califobnia 
 
 Fresno clay loam. 117, 118. Kirkwood .sllty clay abode, 1 H. 
 
 coarse sand, IBO, 151. 
 fine sand, 108, 149. 160, 161,, 
 
 163. Lake and marsh, 106, 149, 156. 
 
 " fine sandy loam, 53, 108, 126, Lewie, 117, 119. 
 
 Ill: III' ul- '"'■ '''• ''"'L'^^t- «»• 
 
 gravel, 14^, 161. Llvermore clay, 109, 110. 
 
 gravelly sand, 153, 163. " clay loam, 117, 119. 
 
 " loam, 127, 129, 160. fine sandy loam, 141. 
 
 loamy coarse sand, 151. " gravelly sandy loam. 137, 
 
 red sand, 154, 160, 161. 138. 
 
 sand, 108, 152, 153, 154, 160. loam, 127. 130. 
 
 161, 162, 163. ' silty fine sandy loam. 148. 
 
 sandy loam, 53, 140, 144, 145, I^oam, 63, 81, 89, 91, 107. 
 152, 160, 161, 163. Loam adobe, 107, 121. 
 
 Fullerton sandy adobe, 122, 134, lei, 1^°^"^^ coarse sand, 107. 
 
 162, 163. Los Angeles sandy loam, 130. 161. 
 
 Galveston clay, 106, 109, 110, 161, 162. 
 
 Gila clay loam, 117, 118, 163. Madera clay loam, 117, 119. 
 
 " fine sand, 153. " coarse sand, 150, 151. 
 
 fine sandy loam, 139, 140, 161. " fine sandy loam, 139, 141. 
 
 163. " sand, 152, 153. 
 
 loam, 127, 129, 161, 163. " sandy loam, 144. 146. 
 
 silt loam, 125, 161, 163. Marcuse clay loam, 117, 119. 
 
 Gravelly clay loam. 107.^^ ^^^ j^,,,,,p, ^-^/f ",7, '--• 1^6, 139. 
 
 " l^n"?' 7n^ ^"'- " gravelly loam, 109. 135. 
 
 136, 141, 161, 162. 163. 
 
 sand, 107. 
 
 " sandy loam, 107. 
 Grldley loam, 127, 129 . 
 
 " sandy loam, 144, 145. 
 
 sllty clay loam. 120. 121 
 
 gravelly sand, 148. 162.163. 
 loam. 129. 160. 162. 
 sand. 152. 153, 163. 
 sandy adobe, 134, 160. 
 sandy loam, 144, 146, 161, 
 
 Hanford clay adobe. 111, 113, 162. 
 
 clay loam, 117, 118. 126. 160.,, ' 162. 
 
 161, 162, 163. Marsh. See Lake and Marsh, 
 
 coarse sand, 150, 151. Marysvllle silt loam, 125, 126. 
 
 " Tn^e'slnri^l^l^'?: Ill" .162.Maywood gravelly sandy loan.. 137 
 
 IftQ i.oo. 
 
 fir,o oonH^f i^or,^ 1QQ iAn " fine sandy loam, 139. 141 
 
 nne sandy loam, 139, 140, •• ir>Qm 197 iQn 
 
 " graVel' US' Wl '''' '''' " slfTiolV.: lit; 126. 
 
 loim i?7 i?q ifii Silty Clay loam, 120. 121 
 
 " sS," 152,' ill: III: 161, 162,M«^^°^- 91. 106. 149, 156, 160. 
 
 163. Media clay adobe. Ill, 113. 
 
 sandy loam, 144, 145, 161. " coarse sandy loam, 151. 
 
 silt loam, 125, 126, 140, 162. " fine sandy loam, 139, 141. 
 Hardpan. 68, 157. sandy loam, 144. 146. 
 
 Heavy, 90. Medium sand, 55, 56, 58, 71. 
 
 Honicut loam. 127, 129. Mocho fine sandy loam, 139, 141. 
 
 " gravelly fine sandy loam, 137, 
 Imperial clay, 109, 110, 161. " loam, 127, 130. 
 
 clay loam, 117, 118, 161. " sandy loam, 146. 
 
 fine sandy loam, 129, 161. Modesto loam. 127. 130. 
 
 '■ grallny loam. 136, 161. TT^'^l «a"«iy l^^"!' l^*. 146. 
 
 loam, 118, 161, 163. Muck. See Peat. 156. 
 
 sand, 152, 153, 161, 163. 
 " sandy loam, 140, 144, 145,.. , , , ,,.,,,,-„ 
 
 161, 163. Norman clay adobe. 111, 113. 160. 
 
 silt loam, i25, 161, 163. 
 Indio gravelly loam, 135, 136, 161. Oakdale coarse sandy loam, 151. 
 fine sandy loam, 139, 140, 149, " sand. 152. 154. 
 
 161. " sandy loam, 144, 146. 
 
 fine sand, 145, 149, 161. Orland fine sand, 152, 160. 
 
 .sand, 153. 161. " fine sandy loam. 139. 141, 160. 
 
Index to Soil Names 167 
 
 Oxnard clay loam, 117, 119, 130, 161, Sacramento heavy clay, 111. 
 
 162. " loam,' 127, 131, 160. 161. 
 " clay loam adobe. 123, 161, 162. " sand, 152, 154. 
 
 163. '• sandy loam. 144, 147. 
 
 " fine sandy loam, 139, 142, 162. " silt loam, 125, 126, 160, 
 
 gravelly loam, 135, 136, 162, 161, 162. 
 
 163 " sllty clay, 116. 160. 
 
 loam, 119, 127, 130, 140, 161, " silty clay loam, 120, 121, 
 
 162, 163. 160. 
 
 sand, 152, 154, 161, 162. 163. Salinas gray adobe, 111, 113, 162, 163. 
 " sandy loam, 144, 146, 162. 163, " shale loam, 136, 162. 163. 
 
 " silt loam, 118, 125, 126, 160,Salslpuedes loam ,128, 131. 
 
 162, 163. Sand, 51, 58, 64, 68, 76, 81, 84, 89, 107. 
 
 •D„,.„^ , , J u 100 San Gabriel gravelly loam, 136, 162. 
 
 Pajaro clay loam adobe. 123 .< gravelly sand 148 162. 
 
 fine sandy loam, 139, 142. .. sandy loam, 146, 162. 163. 
 
 light silt loam. Sandhill. See Dunesand. 
 
 loam, 127, 130. c!„„^„ „/i„u^ m-? 
 
 sand 154 Sandy adobe, 10(. 
 
 sandy loam, 144, 146. Sandy clay, 89. 
 
 silt loam, 125, 126. Sandy loam, 56, 70, 71, 89. 107. 
 
 T>«a't ^7^"?^ ^Ina' }Iq IKK 1K« i«iSan Joaquin black adobe, 123. 124. 
 ^^^^'J^nJq- ^^^' ^^^' ^^^' ^^^- ^^^' 160. 161. 162. 163. 
 
 IDZ, IDO. •• finv nrlf>hf> 111 114 
 
 Placentia clay loam, 90, 117, 119, 180, « ^j|^ loamf 117 119 ' 
 
 11 ™ ^ ., nn ,oo " Clay loam adobe, 123, 
 
 clay loam adobe, 90, 123, 124 162. 
 
 124, 160. „„,.., " fine sandy loam. 139, 
 
 coarse sandy loam, 90, 147, I43 ig2. 
 
 « 1^2- " gravelly loam, 135, 136, 
 
 fine sandy loam, 90, 139, IgO 
 
 iJl^'qn^ii^<f^97^^iq^rf^ifi? " gravelly sandy loam, 
 
 loam, 90, 119, 127, laO, 163. J37 j3g 
 
 ^o^"], t^o^e^ 52 90 121. .. loam,' 128,"l31, 160,163. 
 
 ^ • ^i'u ^•^•oA ,'o. ,<,« " red adobe, 124, 134, 160, 
 sandy adobe, 90, 134, 160, 162. 
 
 l^- , „„ .on 1^0 " sand,'l52, 154, 160, 161. 
 
 r.i^„o„ i.^ 144, 147,160, 161 162,163. - ^andy loam. 144. 147, 
 
 Pleasanton clay adobe. 111, 113. 160 162 163 
 
 ;; gravelly clay loam, 120 ganta Clara sand, 152. ' 
 
 gravelly sandy loam, 137,santa Cruz loam. 128. 131. 
 
 • " sand 154 
 
 l^^^' \^'''J^^^'aa i^.7 " sandy loam, 52, 144, 147. 
 
 fi^^ L J^ 1^1 '^^ ^^^- Santa Rita clay adobe. 111, 114. 
 
 fine sandy loam. « innm 19S 1^1 
 
 Poplar fine sandy loam, 139. 142. .. siltv clav loam 1^0 121 
 
 124. Santiago silt loam, 118, 125, 161, 162, 
 
 " coarse sandy loam, 151. ,, ^ 1^3. ,„„ ,^„ 
 
 " loam 127 131 fin® sandy loam, 139, 143, 
 
 163. 
 
 Redding gravelly loam, 135, 136. lei.gheridan sTndv loa^i^'99''^l'4ri47 162 
 gravelly sandy loam, i38.»ne"aan sanay 10am »» i44, 14/. ibz. 
 
 " loam 127 131 161 Sierra adobe, 124, 134, 160, 161. 
 
 Residual, 54, 94, 96.' ' ' " clay loam, 117, 119, 162. 
 
 Riverwash, 106, 155, 160, 161,162,163. " loam, 122, 128, 131. 
 
 Rock outcrop, 155. loam adobe. 121, 122, 131, 162. 
 
 Rough stony land, 106, 155, 161, 163. " sandy adobe, 134, 161. 
 
 " sandy loam, 144, 147, 162. 
 
 Sacramento clay, 53, 109, 110. <,„/' ,, ^V'^J^'^T' ^^^' ^^^• 
 
 clay adobe. 111, 113. f ! *' ^\' ^^'^^^ V;. 
 
 clay loam, 117, 119, 163. Silty clay. 107, 106. 
 
 fine sand, 149, 152. Silty clay adobe, 107. 
 ""^60^161 ^°''™' ^^^' ^*^' Silty clay loam, 90, 107. 
 
 gravelly sandy loam, Silty fine sandy loam, 107. 
 
 137, 138, 160, 161. Silt loam, 56, 58, 66, 71, 89, 107. 
 
168 
 
 Sou^ OF California 
 
 Sites clay adobe, 111. 114. 
 
 " clay loam adobe. 123, 124. 160. 
 gravelly sandy loam, 137, 138. 
 •' loam, 128, 131. 160. 
 " sandy loam, 144, 148, 160. 
 silt loam. 125. 127. 
 Soledad gravelly sand. 148. 162. 163 
 Stockton clay adobe. 111. 114. 163. 
 clay loam. 117. 120. 
 "^ clay loam adobe, 52, 123 
 
 124, 161. 162. 163. 
 " fine sandy loam. 139, 143 
 
 160. 163. 
 loam 128, 132, 163. 
 loam adobe, 121, 122. 163. 
 silt loam. 125. 127, 163. 
 Stony clay loam. 107, 
 Stony loam, 107. 
 Stony sandy loam, 107. 
 Sunol loam, 128. 132. 
 Sutter clay. 109, 111. 
 
 clay loam adobe, 123, 124. 
 loam, 128, 132. 
 sandy loam, 144, 148. 
 
 Tehama clay. 109. 111. 
 
 " gravelly loam, 136. 
 silt loam, 127. 
 Tassajero clay loam, 117, 120. 
 Tuscan stony loam, 122. 
 
 " stony sandy loam, 137. 
 
 Ulmar fine sandy loam, 139, 143. 
 loam. 128. 132. 
 
 Vallecltos clay adobe. 111. 114. 
 loam, 128, 132. 
 " stony clay loam, 122. 
 
 Very fine sand, 55, 89. 
 Vina clay adobe. 111. 114. 
 clay loam. 117. 120. 
 fine sandy loam, 137, 139. 143. 
 loam. 128. 132. 
 " gravelly fine sandy loam, 137. 
 silt loam, 127. 
 
 Watsonvllle clay loam adobe, 123, 124. 
 loam, 128, 132. 
 " sandy loam. 144, 148. 
 
 Willows clay. 109, 111. 160. 
 
 clay adobe, 111, 114, 160. 
 clay loam, 117, 120, 160. 
 loam, 128, 132, 160. 
 silty clay loam. 120, 121, 160. 
 
 Yolo clay, 109, 111. 
 
 " clay loam, 117, 120. 
 
 fine sandy loam, 139, 143. 
 " loam, 128, 133. 
 " silt loam, 125. 127. 
 " sllty clay, 116. 
 
 GENERAL INDEX 
 
 Absorption, 60. 
 Abused soils. 17. 
 Acid rocks. 11. 
 Adaptability to crops, 92. 
 Adobes, the, 108. 
 Adsorption, 60. 
 Aggradation, 31. 
 Agricultural geology, 7. 
 Air retained. 30. 
 Alkali, black. 53, 157. 
 Alkali, limit.s of endurance, 158. 
 Alkali soils. !)2. 1^7 
 Alkali, wliite, 53, 157. 
 Aluminum. 15, 17. 
 Alluvial cone, 33. 
 Alluvial, plain, 21. 33. 
 Ammonia, 76, 78. 
 Amphibole, 14. 
 Animal life in tlie soil. 82. 
 Ants. 83, 85. 
 Atmosphere. 9, 25. 
 Apatite. 15. 
 Aqueous rocks, 11. 
 Argillaceous material. 11. 
 Arid regions, 34, 35, 74, 76, 84, 90. 
 
 Bacterial. 18. 74, 76, 77, 81, 82. 85. 
 aerobic, 78. 
 anaerobic, 78. 
 " bacillus, 78. 
 
 Bacterial, bacillus mycoldes, 78. 
 
 baggiatoa, 78. 
 
 effect of moisture. 80. 
 
 favorable conditions. 80. 
 
 effect of temperature, 80. 
 " micrococcus, 78. 
 
 number of, 28, 80. 
 
 splrllli, 78. 
 " unfavorable conditions. 80. 
 
 vibrio. 78. 
 Base, level, 22, 34. 
 Base leveled plain, 23. 
 Basic rocks, 11. 
 Basin, 22. 
 Bedrock, 11. 
 Beetles. 83, 85. 
 Bergmeal, 35. 
 Blotite. 14. 
 Boulder clay, 35, 73. 
 Broken block lands, 23. 
 
 Calcareous material, 11. 
 
 Calclte. 14. 
 
 Calcium, 15. 
 
 California, area, 37. 
 
 Canyon, 32. 
 
 Capillary water, 62. 63. 
 
 Carbonation. 26. 
 
 Carbonic dioxide, 19, 28, 69. 78. 
 
 Cascade Province, 42. 46. 
 
Qenebal IND£X 
 
 169 
 
 Case harden, 68. 
 
 Changres In names, 109. 
 
 Channel, 32. 
 
 Checkingr. 68. 
 
 Chemical analysis. 74. 
 
 Chemical work of atmosphere, 26. 
 
 Chlorite, 15. 
 
 Chlorine. 15, 17, 60. 
 
 Classification, 47. 158. 
 
 Coarse sands, the, 139, 150, 151. 
 
 Coarse sandy loams, the, 139. 151. 
 
 Coastal plains, 20, 24. 
 
 Coast Provinces, 38, 45. 
 
 Coast Range^ northern, 39. 
 
 Coast Range, southern, 39. 
 
 Cohesion, 69. 
 
 Colloidal rocks, 12. 
 
 Colusa Area. 102. 
 
 Conglomerate, 12. 
 
 Correlation, 108. 
 
 Critical moisture, 65. 
 
 Crumb structure, 68. 
 
 Crystalline rocks, 11. 
 
 Degradation, 31. 
 Degraded plains. 21. 
 Delta, 21, 33. 
 Deposition, 33. 
 Desert, 40. 
 Dikes, 33. 
 Distributaries. 33. 
 Dolomites. 12. 
 Drainage. 30, 62. 70. 
 Drift, 12. 
 Drift plains, 21. 
 Drumlins. 36. 
 Dunes, 26. 
 
 Dunesands, the, 149. 
 Dust. 26. 
 
 Earth, the. 8. 
 Earth worms. 82, 85. 
 Electricity. 71. 
 Elements, 15. 
 
 " atmospheric. 17. 
 
 Enzymes. 81. 
 Eollan plains, 21, 24. 
 Eolian rocks, 12. 
 Eollan soils, 47. 
 Eskers, 35. 
 Evaporation. 66. 
 
 Factors, 10. 
 Pan. 33. 
 Feldspar, 14. 
 Ferns. 81. 
 Ferruginous. 11. 
 Fertilizers, mineral, 59, 74. 
 " organic, 59, 74. 
 
 Film water. 62. 64, 68. 
 Fine sandy loams, the, 134. 
 Flocculation, 16. 
 Flood plain, 21. 32. 
 Fragmental rocks, 12. 
 Fungi, higher, 81. 
 
 Geologic provinces. 43. 
 Geomorphogeny, 25. 
 Geomorphology, 205. 
 
 Glacial drift, 35. 
 
 plains, 21. 
 Glaciers, 8, 35. 
 Gneiss, 12. 
 Gradation. 31. 
 Granite, 11. 12, 
 Granular structure. 65, 68. 
 Gravel, 139. 
 
 Gravelly fine sandy loams, the, 137. 
 Gravelly loams, the, 134, 135. 
 Gravelly sands, the. 139, 148. 
 Gravelly sandy loams, the, 134. 
 Gravity, 69. 
 
 Great Basin, 23, 40, 45, 46. 
 Great Valley, 22, 39, 44, 96. 105. 
 Greenstone. 12. 
 Ground water level. 66. 
 Ground water surface, 66. 
 Gravitational water, 62. 
 Gyppum. 14, 64. 
 
 Hardpan, 68. 157. 
 Hematite, 15. 
 Highlands. 22. 
 Hills, 22, 
 
 Hills of accumulation, 22. 
 Hills of erosion, 22. 
 Humus, 66, 82, 83. 84. 
 Hydration, 26. 
 Hydrosphere, 9. 
 Hygroscopic water, 63. 
 
 Ice, 30. 
 
 Igneous rocks, 12. 
 Imperial area, 102. 
 Indurated, 11. 
 Interment valleys, 22. 
 Intrusive rocks, 12. 
 Iron. 15. 17. 72, 73. 
 Isolated mountain. 22. 
 
 Karnes, 35. 
 Kaolin. 14. 
 Klamath province, 42, 46. 
 
 Lacustrine plain. 21. 
 Lake, plain, 20. 21. 
 Lakes, 34. 
 Lakes, glacial, 35. 
 
 " intermittent, 35. 
 
 " volcanic, 35. 
 Land forms, 20. 
 Lassen Peak, 23. 
 Lava, 12. 
 Lichens, 81. 
 Life in soil. 78. 
 Lime, 14. 16. 60. 78, 81, 83. 
 Limestone, 12, 83. 
 Lithosphere. 9. 
 
 Livermore area, 97, 99. 103. 105. 
 Lepidollte, 14. 
 Levee, 34. 
 
 Loam adobes, the, 120. 
 Loamy coarse sand, 139. 
 Loess, 13, 50. 
 
 Magnesia, 17. 
 Magnesium. 15, 59. 
 Mantle rock, 11. 13. 
 Marble. 13. 
 
170 
 
 Soils of California 
 
 Marginal moraines, 8S. 
 Marl, 13, 35. 
 Mature valley, 34. 
 Maximum moisture, 66. 
 
 Minerals, 11. 13, 88. 
 
 Modesto-Turlock area, 102. 
 
 Molds. 82. 
 
 Mosses, 81. 
 
 Mountain, 22. 24. 
 
 Mt. Lyell, 41. 
 
 Mt. Shasta, 23, 27. 
 
 Mt. Wliitney, 38. 41. 
 
 Muscovite, 14. 
 
 Names, changed, 160, 161. 162, 163. 
 
 Names, common, 51. 
 
 Nitric acid, 78. 
 
 Nitrogen, 15, 18, 60, 69, 76. 78. 82. 
 
 Nitrogen from air, 80. 
 
 Ooze, 13. 
 
 Optimum moisture, 63, 65, 66. 
 
 matter, 72. 76, 77. 
 Outcrop, 11. 
 Outer valley, 32. 
 Oxidation, 26. 
 
 Pajaro area, 110. 
 
 Paragonite, 14. 
 
 Peat. 149. 
 
 Peneplain, 23, 31. 
 
 Phosphorous, 15, 16, 60. 74. 78, 81. 
 
 Piedmont alluvial plain, 33, 
 
 Plains, 20. 
 
 of degradation, 20. 
 Plasticity, 68. 
 Plateaus, 21, 24. 
 Poisoned soils, 17. 
 Potash, 16, 58, 60, 78, 81. 
 Potassium, 15, 59, 60. 
 Pyroxene. 15. 
 
 Quartz, 13. 
 Quartzite, 13. 
 
 Recent stream deposits, 33. 
 
 Red Bluff area, 98. 103. 
 
 Regolith, 13. 
 
 Riverwash, 149. 
 
 Rocks, 11. 
 
 Rough, stony lands, the, 149. 
 
 Run off, 28. 
 
 Saccharomycetes, 78. 
 Sacramento area, 99, 100. 
 Sandstone. 13. 
 Sandunes. 26. 
 Santa Ana area, 104. 
 Seasons, 8. 
 
 Sedimentary rocks, 11. 
 Sediment, 32. 
 Seepage, 31. 
 
 Series, 88, 90. 
 Alamo, 95, 105. 
 Altamont, 94. 97. 
 Alviso, 95. 
 Anderson, 95, 103. 
 Arbuckle, 95, 103. 
 
 Arnold, 94, 96. 
 Capay, 95, 104. 
 Contra Costa, 94, 97. 
 Corning. 95, 104. 
 Diablo, 94, 98. 
 Danville, 95, 99. 
 Daulton, 94, 96. 
 Dublin, 95, 100. 
 Elder, 95, 103. 
 Encinaz, 94, 97. 
 Esparto. 95, 102. 
 Feather, 95, 105. 
 Fresno, 95, 103. 
 Galveston, 95. 
 Gila, 95. 101. 102. 
 Grldley, 95, 104. 
 Hanford, 40. 95, 103. 
 Imperial, 88, 95, 102. 
 Indio. 95. 100. 
 Klrkwood. 95, 104. 
 Livermore, 95, 100. 
 Madera, 96. 
 Maricopa, 95. 99. 
 Maywood, 95, 103. 
 Media, 94, 97. 
 Mocho, 103. 
 Oakdale. 95, 102. 
 Orland, 95, 102. 
 Oxnard, 95, 99. 
 Pajaro. 95, 102. 
 Placentia, 90, 95, 99. 
 Pleasanton, 94, 97. 
 Portersville, 94, 96. 
 Redding, 95, 104. 
 Sacramento, 88, 95, 105. 
 Salsipuedes. 95, 99. 
 Sand, 139. 
 
 San Joaquin, 88, 96, 106. 
 Santa Cruz, 94, 98. 
 Santiago, 95, 104. 
 Santa Rita, 96, 105. 
 Sheridan, 95. 99. 
 Sierra, 94, 97. 
 Sites, 95, 100. 
 Stockton, 96. 105. 
 Sunol, 95, 100. 
 Sutter, 95, 99. 
 Tehama, 94. 98. 
 Tuscan, 94, 98. 
 Ulmar ,95, 100. 
 Vallecitos, 94, 98. 
 Watsonville, 94, 98. 
 Yolo, 95, 102. 
 
 Shale. 13. 
 
 Sierra Madre Range. 33. 
 
 Sierra Nevada province, 37, 43. 
 
 Sierra Nevada Range, 23, 33, 43, 47. 
 
 Silicon. 15. 60. 
 
 Silty fine .«!andy loams, the. 139. 148. 
 
GENsaAL Index 
 
 171 
 
 Slate, 13. 
 Sodium. 15, 59. 
 Soils, adaptation of, 75, 92. 
 atmosphere, 68, 69. 
 classes, 88, 105. 
 color of, 72, 76. 
 creep, 28. 
 dark, 70, 73. 
 deep, 70. 
 " deterioration. 86. 
 fertility, 74, 87. 
 fine, 71. 
 " forming materials, 70. 
 " forming processes, 10. 
 heavy, 72. 
 light, 72, 73. 
 " minerals, 11. 
 " moisture, 62, 70, 80, 91. 
 " movement, 85. 
 
 names, 47, 89, 108. 109. 
 odors, 74. 
 
 particles, 54, 55, 56, 60. 88. 
 " permanence. 86. 
 " processes, 10. 
 " provinces, 58. 
 
 self purifying, 78. 
 series, 54. 
 " solution, 59. 
 " temperature, 69, 80. 
 " temperature ,69. 80. 
 texture, 57, 62, 70, 72. 
 types, 7, 88. 
 Special soils, 106. 
 Stony clay loams, the, 122. 
 Stony loams, the, 122. 
 Stony sandy loams, the, 134, 137. 
 Strata, 11. 
 
 Stream, overloaded, 32. 
 Streams, 31. 
 Structural plains, 20. 
 Structural valleys, 22. 
 
 SubBOil, 84. 
 
 " calcareous, 85. 
 Sulphur, 15. 17. 
 
 Temperature, 26. 
 
 Terminal moraine, 35. 
 
 Till, 13. 
 
 Tilth, 65. 
 
 Topographic provinces, Zl. 
 
 Toxic bodies. 77. 
 
 Tufa. 13. 
 
 Tuff, 13. 
 
 Valley forms, 34. 
 Valleys, 22. 
 Valley trains, 36. 
 Virgin soil. 25. 
 Vitreous rocks, 11. 
 Volcanic lands, 23. 
 
 Water, 28. 
 
 absorbed, 61. 
 
 capillary, 62. 
 
 film, 62, 64. 
 
 gravity, 62. 
 
 hygroscopic, 62, 63. 
 
 hydration, 62, 64. 
 
 work of. 28, 86. 
 " solvent action of, 29. 
 " storage, 29. 
 
 table, 66. 
 
 undergound, 30. 
 " vapor, 63. 
 Weathering, 27. 
 Wind erosion, 26, 86. 
 Wind worn rocks, 21. 
 Woodland, area, 100, 102. 110. 
 Worn down plains, 21. 
 
 Young valley, 34. 
 
OCT 29 1313