S^fek^^ 1 |F|^ Class _S531_ Book_ ^_a_ Gopyri^htN^ COPYRIGHT DEPOSIT. SOILS Their Properties, Improvement, Management, and the Problems of Crop Growing and Crop Feeding By CHARLES WILLIAM BURKETT Director of the Agricultural Experiment Station, Kansas State Agricultural College Where grows ? — Where grows it not ? If vain our toil. We ought to blame the culture, not the soil. Pope. ILLUSTRATED NEW YORK ORANGE JUDD COMPANY LONDON Kegan Paul, Trench, Trubner & Co., Limited 1907 LtSRARY of CONGRESS Two Cooles Received SEP 6 I90r .CooyricW Bntry CLASS 'A XXc, N6. COPY B. CorYRIGHT, 1907, BY ORANGE JUDD COMPANY All Rights Reserved [entered at stationers' hall, LONDON, ENGLAND] ACKNOWLEDGMENTS The author is under obligations to many friends for helpful suggestions and illustrations. Especial credit is due the following for illustrations used on the pages indicated : Professor E. O. Pippin, of Cornell University, 29, 31, 34, 36, 65, 91, 94, 113, 173, 174, 192. 195, 198, 204, 218, 236, 266, 280, 283, etc. ; Professor A. M. Ten Eyck, of the Kansas Experiment Station, 2, 13, 20, 47, 197, 270; Professor Oscar Erf, of Kansas Experiment Station, 207, 209, 211, 259; Professor Charles E. Thorne, Director of the Ohio Experiment Station, 100, 105 ; Dr. C. G. Hopkins, of the Illinois Experiment Station, 268; George K. Helder, 177, 178, 180, 182, 183, 194, 202. Thanks are also due the Orange Judd Company for many photo- graphs and B. F. Williamson for the line drawings. CONTENTS CHAPTER PAGE Introduction i I. The Soil Makers 7 II. The Soils that Living Things Have Made ... 17 III. What We Find in Soils 2^ IV. Concerning the Texture of the Soil 34 V. How Plants Feed 44 VI. The Elements that Plants Use 52 VII. How Plant Food is Preserved 62 VIII. Getting Acquainted with Plant Food 71 IX. The Potential Plant Food : Its Stores and Nature 79 X. The Role that Tillage Plays 88 XL Liming the Land : A Corrective for Acidity . . 90 XII. The Quest of Nitrogen 108 XIII. The Release of Soil Nitrogen: The Return to the Air 117 XIV. Nitrification : Nitrogen Made Ready for Plants . . 124 XV. Reclaiming Lost Nitrogen : the Call to the Air . . 132 XVI. Soil Inoculation : How Done 143 XVII. Draining the Land 152 XVIII. Soil Water: How it is Lost; how it May be Held 164 XIX. Dry Farming: A Problem in Water Conservation 176 XX. Tillage Tools : What They are for ; how to Use Them 185 XXI. The Cultivation of Crops: The Tools and Purposes 197 XXII. Stable Manure : Its Composition and its Preservation 206 XXIII. Handling Manure on the Farm 216 XXIV. Buying Plant Food for the Soil 227 XXV. Using Chemical Manure Intelligently 238 XXVI. Mixing Fertilizers at Home 246 XXVII. Dairying: .A.n Example in Soil Building .... 255 XXVIII. Rotation of Crops 266 XXIX. The Old, Worn-out Soils : What we May do for Them 282 XXX. Conclusion : A Bit of Philosophy 291 ILLUSTRATIONS PAGE Only the Roots Remain Behind 2 A Bit of Earth's Clothing 5 Gradually Changing from Rock to Soil 8 Cover Crop for the Orchard I2 A Field of Corn Carried Away by a Raging Flood .... 13 Just after a Flood 15 Soil Builders at Work 18 Alfalfa Roots Go Deep into the Soil 20 A Crop that is Hard on the Soil 24 Section of Soil Showing Air Spaces and Particles .... 26 On Two Types of Soil 2Q Crop Adaptation 31 A Case of Bad Texture 34 Taking Soil Samples 36 The Pore-space of the Soil 2>7 A Soil that Needs Humus 39 Circulation of Water in the Soil 40 Vegetable Matter Aids the Soil in Holding Water .... 42 Trees in the Prairie Region 43 How Plant Food Gets into the Soil 44 The Underside of a Leaf with a jNIicroscope 46 Oats 47 Cross-section of Root Hair 48 Root Hairs 48 How the Sap Current Moves 49 The Greater Part of this Wonderful Crop Comes from the Air 55 Getting Humus into the Soil 59 Cotton Plant Above and Below the Ground 62 A Root Hair with Soil Attached 64 Making Plant Food Available 65 At Work in the Corn-field 67 Getting Ready for Cotton 68 Poor Grass, Poor Cattle 7Z Vlll ILLUSTRATIONS Corn Growing in Surface and Subsoil 76 A Crop that Calls for Much Nitrogen 79 A Crop that Gets Nitrogen from the Air 82 A Sure Way to Improve the Soil 84 Increasing the Nitrogen with Legumes 86 Alfalfa Roots : Vegetable Tillage Tools 89 A Good Job of Plowing 91 Plowed for the First Time 93 Effect of Plowing Wet Land 94 Limed and Unlimed Land 100 Using the Lime Spreader 105 A Magnificent Crop of Beans 113 Two Kinds of Bacteria Found in Decaying Vegetable Matter . 120 Bacteria Usually Found in Decaying Organic Matter . . . 121 Some Bacteria that Cause the Fermentation of Urine . . . 123 Nitrifying Bacteria 127 Losing Nitrogen and Humus 132 Root Tubercle Bacteria 139 Back of Good Tillage is the Well-bred Farm Horse . . . 142 Some Legume Roots Showing Root Tubercles 145 Growing Bacteria in the Laboratory 149 Alfalfa: the Best All-round Crop in America 150 Red Clover Roots i53 Soil Temperature i55 A Way to Help the Drainage 156 Losing Soils by Heavy Rains 158 The Result when Water was Secured and Held 164 Efifect of Cultivation of Corn Crop 165 Cultivation Checks Evaporation 166 A Home-made Roller 169 Disking the Ground before Plowing 171 A Stone Mulch i73 A Good Mulch I74 Kaffir Corn I77 Corn Planted with Disk Furrow-opener Attached .... 178 Double Disking the Land 180 "Out There in Kansas" 181 Sub-surface Packing 182 Dry Land Farming 183 Ideal Plowing 186 Furrow Slices that are too Flat 186 ILLUSTRATIONS IX Plowing Levees for Rice i88 Everything is Done at One Operation 190 Where Rolling Does Little Good 192 The Acme Harrow 194 A Step in Soil Preparation 195 Corn Roots 197 Cultivating the Orchard 198 The Gentle Art of Cultivation 200 Catalpa Tree with One Season's Growth 202 Losing Water from Soil 204 The Erf Stabling System 207 Losing Fertility 209 A Covered Barnyard 211 Letting the Manure Get Away 216 A Common Way but Poor Practice 218 Hauling Manure to the Field 220 Manure Spreader at Work 221 Crimson Clover in the South 224 Cow-peas and Fertilizers and a Poor Soil 227 A Case where All Three Elements Are Needed 228 Our Common Fertilizing Materials 230 Where Acid Phosphate Pays 233 A Muck Soil that Profitably Uses Potassium 236 Plant Food in a Bag of Fertilizer 241 The Bag and the Plant Food in It 243 Fertilizers Pay Best when Good Plowing Has Been Done . . 247 The Soil that Tells Its Own Story 251 Where Alfalfa Prospers Dairying Prospers 256 Complete Irrigating System with Dairy House and Residence Attached 259 A Balance Wheel in Farming 260 Two Kinds of Farming 262 Relative Amounts of Plant Food when a Ton of Each is Sold 263 Crop Rotation 266 Corn in Growing Stage 267 Corn at Harvest Time 268 Cow-pea Roots 270 Crop of Corn and Cow-peas the Same Year 272 Close Rotation of Crops 278 Crop Rotation and Mixed Farming Go Hand in Hand . . . 277 Timothy May Go in Rotation 280 X ILLUSTRATIONS In Perfect Condition 283 What Humus Does in the Soil 285 Grow Legumes Constantly 288 One Kind of Farming that Improves the Land 291 A Sure Way to Ruin the Farm 293 Seven of Our Leading Products 295 Intensive Farming 296 A Department of the Farm Factory 298 "Thro' Wood and Mead" 299 THE PLOW By V. F. BoYSON [By courtesy Everybody's Maga::inc.] I am a worker. Sleep on and take your rest Though my sharp coulter shows white in the dawn: Beating through wind and rain, Furrowing hill and plain Till twilight dims the west And I stand darkly against the night sky. I am a worker, I, the plow. I feed the peoples. Eagerly wait on me High-born and low-born, pale children of want: Kingdoms may rise and wane, War claim her tithe of slain, Hands are outstretched to me. Master of men am I, seeming a slave, I feed the peoples, I, the plow. I prove God's word true — Toiling that earth may give Fruit men shall gather with songs in the sun. Where sleeps the hidden grain Corn-fields shall wave again; Showing that while inen live Nor seed nor harvest time ever will cease. I prove God's words true, I, the plow. INTRODUCTION THE EARTH'S CLOTHING It has been calculated that if the earth were tunneled direct to the other side, 7,918 miles would be traveled in making the journey. But a difficulty would be met in this endeavor : After going a few miles, the heat would be so intense that further progress would be impossible. For as we descend into the earth, after going a very little way, the temperature rises at the rate of i degree for every 50 feet, a rate that is universal over the earth's surface, and for the greatest depth attained. From the known laws of the conduction of heat the conclusion follows that at a depth of 15 to 20 miles below the surface the earth is red hot, while the heat 100 miles deeper, if applied at the surface, would liquefy all mate- rials at the surface crust. These known facts have led to an hypothesis that the interior of the earth is more or less fluid, and that the crust is only a thin shell floating on the molten globe. However, the earth as a body is very rigid and sub- jected to a pressure so great that despite the high tem- perature, the interior is locked into a solid mass as rigid as steel itself. But after all, we are coiicerned less with the interior of the earth and with the surface more. Our aim is to know the outer covering — the clothing that encloses this hidden interior — and to use its history to our profit and good. Every science has lajjored with the secret that is hidden in this clothing of the earth that the world might know some of the stories it has to tell : of the 2 INTRODUCTION strange forms of vegetation that once visited here ; of the bizarre creatures that peopled it in old days — before man came and before the myriads of present-day friends and foes had sprung into existence ; of the monsters that throve and multiplied and brought fear and death to weaker kind ; of the hideous reptiles that crawled over the slimy domain, battling with each other or with the ONLY THE ROOTS REMAIN BEHIND This picture is an example of the power of water in soil making denizens of the forest; of primitive man — weak, dull, savage, and yet endowed with more cunning of brain — fulfilling his mission and preparing the way for better and higher tribes ; of all the agencies that have been at work in the making of the garment that covers this great body ; of the soil, the real covering, and all it means : these many stories have been told in rock and stone and INTRODUCTION 3 in slowly perishable materials, and so clearly told that man reads and reflects and profits in the lessons that are learned. And of some of these we want to learn in the pa,2^es that follow. The soil: the clothing of the earth. — The real cloth- ing" of the earth is the soil — and we are to study it: the good, kind soil that brings us so many useful and beau- tiful and wholesome things. For with the soil is the real beginning of all material things, of all things of worth ; of all things that secure contentment ; of all things that lead to comfort and happiness ; of all things that have to do with food and raiment and shelter; of all things that advance mankind and promote civilization. All of these things spring from the soil — from the simple, inanimate, material thing we call dirt. The earth's clothing includes the soil in all its varia- tions ; includes the dirt in which plants root and feed and grow ; includes the rock and stony structures of sea and mountain ; includes the waters of the soil and of the deep; includes the minerals in the mines that man seeks, often losing his life in the search ; includes the insect, the worm, the bacterium, and every form of life that labors for its usefulness and grandeur ; includes the fruits of field and soil — the life that grows therein and makes food for man and beast; includes the tree that grows and fructifies in forest or orchard ; includes the cultivated crop of every variety and species, of every form and description ; includes every vegetable type that provides raiment, or covering in the open, or when re- moved from its place of growth, becomes house and shelter that protects and guards and comforts; includes everything that has use and that supplies a want in every part of the world and for every purpose. All these things come from the soil, from the magnificent garment 4 INTRODUCTION that clothes the earth. "Before Hterature existed, before governments were known, agriculture was the calling of man. And all the fruits of social progress since then grew from the brown soil." The soil changes its clothing. — The clothing of the earth is a changing one. It is of as many colors as the coat of Joseph. And this clothing changes not in color only, but in texture, in wearing ability, in usefulness. For are there not many soils that had poverty as their inheritance and still others that had only the fullest riches? Yet both kinds meet at a common point so often — the rich have become poor, the poor have become rich. All over our land this change is observed. To man's credit, however, we are now at a point in farming where this may be corrected, for we realize that the soil is capable of change and of improvement : it offers a great opportunity for thought and study. Applied here, knowl- edge brings abundant returns. The soil and the subsoil. — There are two layers of this clothing : the soil and the subsoil, and of course we must give due weight to both with any discussion of crop pro- duction or in any method of land management. In both soil and subsoil are found organic and inorganic mate- rials, although the subsoil contains a greater portion of the latter substances than the soil immediately over it. It is in both of these layers that the roots of plants grow, and now that we know more about roots than we did a few years ago, we ought to be able to handle lands with greater certainty and to grow crops with more profit. We know where roots grow ; we know the places in which they feed and just how they do their work. Is this not a practical turn? Roots grow from their tips, and at these points they gather food and drink. With the passing of INTRODUCTION 5 a little time the tip end is sent further on in the search; it grows longer ; it finds a new place to take nourishment. The roots grow on and on and new root hairs form, taking their nutriment from the new and fresh pastures. So all about in the soil they go, just below the surface, a little deeper in the soil top; even in the subsoil (if they can enter it), and all the while they search and seek for plant food that the great body above may be supplied. Fertility is more than soil. — And we should bear in mind that fertility is more than a mere abundance of plant food in the soil (we have learned more about the soil). Fertility is plant food, of course, but in part, only. It is water — just the right amount and served when needed. It is climate — neither too cold nor too hot for the particular plant. It is texture — soil grains of proper size and in ])roper relation to control heat, moisture, and air. It is humus — a goodly amount to supply nitrogen as required, and to help in makmg pleasant and comfort- able the home of the roots. It is tillage — the real, true sort of tillage that provides tilth and mellowness. It is A BIT OF THE KAKTIl's Cl.UTHlNti 6 INTRODUCTION the plant — the right kind for the particular soil. Fer- tility is these and all other requirements that secure a soil environment to the liking" of the growing plant. Hence, the plant food of the soil is an incident, but a necessary incident, just as heat and air and water and tillage and texture are incidents and prerequisites of high production. SOILS CHAPTER I THE SOIL MAKERS Do not think, gentle reader, that I am going to weary you with a long discussion about the history of the ground. The only misgivings the author has had in the preparation of this volume has been the necessity of say- ing these few words that follow about the soil makers, the agencies that have been at work making the soil. Important? Yes, in a way; but if you see the matter as I do, you are more interested in having the soil dem- onstrate what it can do now, rather than to inquire into its line of descent; to be familiar with its ability to do work and to perform to-day, rather than to know its ancestral life of long years ago. First effort in soil making. — To find the first eflfort in soil making we shall have to go back to a time far into the past ; back before man had appeared ; farther back yet than the time when plants had begun their existence. For is it not true that plants must have raiment for their roots — earth in which they may grow and out of which they may get food and drink? We shall have to go back — very far back in the past — when the surface was cooling and forming its crust, when the entire surface of the earth was rock — no ani- mals, no cultivated crops, no trees, no grass — not even the tiniest form of bug or i)lant or beast. For at this time the earth was void and without form, 8 SOILS although surrounded by an atmosphere of mist and vapor. When this rocky and molten mass of earth began to cool, its crust became broken and uneven. But no soil was there, only hard, fire-burned rock. Then centuries passed — thousands and thousands of them. The molten mass had cooled. The darkness that was on the face of the deep gave way to light and change. For the light came from the sun and these rays the rocks absorbed. They felt the refining influence, also, of the air as it played over the wrinkled faces of rock and clifT. At first these two agencies made but little, if any, impression. So hard was the rock, what might air and sunshine do? GkAULJAl.LY CHANGING FROM ROCK TU SUlL But busy bodies, that are at work always and ever, gradu- ally gain their ends, and so these first rocks, now cold, now warm but yet so hard and strong — and so brutal — slowly gave up their determined tenacity and lost some of their strength and hidden power. A little softening, and they were changed, just as the refining influence of good air and much sunshine refines the plant or beast or man that comes under their spell and change. TlIK SOIL MAKERS 9 How the atmosphere assists. — Just as soon as the first rocks were exposed to the weather, remarkable chang-cs then resulted. The rocks, after long exposure, crumbled somewhat; just a few particles, a few tiny grains from time to time fell apart from the whole and dropped to a lower level to be carried away by water ; or they were picked up and carried away by the wind when it rose in sufficient force to defy the mighty giants of rock forma- tion. Of course the wind accomplished but little with each attack. But the wind is ever young; it never grows old, and a thousand years of trial weaken it not. These tiny particles — the first released from rock — represent the beginnings in soil making. And ever since the time, who shall say how long.'' that these first particles were given to the wind, the weather has been at work making soil. The atmosphere assists in soil making because of the chemical action of the gases that compose the air and of the moisture or vapor it holds. The two important gases that are so powerful in making soil are oxygen and car- bonic acid. They are always at work ; they have been at work from the very beginning of time ; and so long as life exists, from the tiniest plant up to the finest devel- oped type of man, oxygen will be required for the work of the world. Oxygen forms oxides by combining with nearly all sorts of materials that are found in the earth. You know how quickly iron rusts when exposed to the air, especially if moist — an oxide of iron has resulted ; not that the iron has been destroyed nor the oxygen of the air that com- bined with it, but the two have united and formed a new chemical compound, powdery in texture and now in a form to be easily combined with acid so as to become food which plants may use. 10 SOILS The carbonic acid of the air serves its part, also, but in another way. It works with water and in this manner: the two substances — carbonic acid and water — readily commingle and produce a liquid that is strong as a sol- vent, effective as a dissolving agent, so as to weaken the rocks, and active as a selective power which seeks the soft minerals of earthy formations and quarries them for plant builders to use. Oxygen and carbonic acid work whether man would have them or not ; they ask not his permit when they shall work nor where ; and neither do they ask on what materials they shall satisfy their desires. They work for Nature and to her they belong, and in this case they re- fuse to bow or to conform to man's wishes. But air and water are usually most effective as soil makers when they are working together, for they accom- plish more and do it more quickly. You have seen per- haps some iron tool that for years has remained in the bottom of a well, the water having made no perceptible headway against it. Because no air was there, rust did not result. And again, you have seen another iron tool kept in an atmosphere that was dry. You note no per- ceptible disintegration because moisture is highly essen- tial for iron to change into its own powdery dust. In dry climates rocks last longer than in moist climates for the reasons explained in reference to the dissolving action of air, carbonic acid, and moisture. Changes in temperature play a part. — In the early days the earth had a larger garment to clothe it than it now possesses. It was very hot — a boiling mass, at first. As time went on, the outer crust became cool, and at the same time this crust hardened and became fixed in char- acter, but only temporarily ; only long enough for the cooled crust to deepen its thickness, when the entire body THE SOIL MAKERS II must contract ; because, you know all matter expands when heated and becomes smaller when cooled. With the cooling of the earth its outer clothing was drawn in, with the result that it was wrinkled — hills here and high mountains there — which continued so long as the con- tractive force was greater than the holding force of the crust. In all this work changes were taking place. Huge beds of rock were thrown up and exposed in an hundred places to air and moisture, where before they were so snugly covered that neither could enter. The earth continued to cool and in some places ice formed. Vapor condensed and dropped as rain. For cen- turies rain had fallen, but as it struck the hard earth it was flung back into the air again as vapor and mist. As the earth gradually cooled, water was thrown back with less vengeance and force. Some of it was left for a consider- able time on the earth, where it had collected in basins, or in crevices in the rock. It was caught here at times by wind-storms that were cold enough to freeze this gathered water. As the water froze, it expanded, forcing many crevices wider, breaking many rocks asunder — and doing what we are pleased to call its share in soil making. It is this change in temperature that assists in soil making — that weakens the original rocks that were ages ago forced from the very bowels of the earth. Rocks such as the granite type — when alternately heated and cooled for a long time — gradually weaken and break. Sudden changes in temperature produce similar results. Temperature is more active when moisture is present. Even in the modern world we see stone buildings, that frequently drop a corner or a slab, due to sudden freezing when saturated with water. You recall with what ease the same may be done with a hammer on a cold day. Since nearly all rocks, even those deeply imbedded in 12 SOILS the soil, contain not a small amount of water, cold be- comes a most potent as well as a most active agent in breaking and pulverizing them and in preparing them for the soil itself. Water wears away the rock. — But water is a soil maker in another way than as a solvent. By simple fric- tion it wears the hardest rock and makes for itself a track in which it may flow with greater ease. This action of the water has been so constant, and so regular, through so many summers and winters, and at work for so many, many centuries, that it has widened and deepened its f'f 'T'.-- ■MM ||£^yd£| t *■ . ■'^"-kA.ia 1 itt P ^ 1 1 ■ m 11 ^g m ^^^2 1^1 m sggg^^ U^i?' i P P H 1 ■ COVER CROP FUR THK ORCHARD Oats are used here, and do good service for protection against water and wind channels in all parts of the earth so that millions and millions of tons of solid rock have been washed from higher to lower levels, the dissolved part being left in lower regions or carried out into the sea, where the ac- cumulations for centuries have made new lands, some of which are now and for long times have been used for the growing of many of the necessities of man. Every time you see moving water in a stream, you see a soil maker at work. With even a light shower the water deepens its color, since the stream, the road and the field THE SOIL MAKERS 13 give up their finest dust, and send real soil downward to a lower level. It is beyond our power to estimate the enor- mous quantity of soil that is moved during a single year. A single illustration will show how great this quantity is: The Mississippi River as it pours into the Gulf of Mexico each year deposits soil sufficient in quantity to cover an area of 100 square miles nearly three feet in depth. Add to this the outpourings of all river systems and you have land areas made each year that equal many a state in size. Whenever a river outflows its banks it leaves deposited on the submerged territory tons and tons of mud — and this mud is valuable soil — often as much as an inch in thickness. In all mountainous regions we have the results of the wearing power of water. Huge caiions, hundreds of feet deep — the Colorado Canon is 2,000 feet in depth — mark the track of the leaps and pourings of water from the mountain summits. When considered in the aggregate, the amount of soil made by water-washing of our thou- A FIELD ui- COKX ( ARKIED AWAY EV A KA(,I.\r. FLOOD 14 SOILS sands of hills and mountains is large. Here we see a mighty force and a powerful agent at work in soil making. The sorting power of water. — In this connection we should not forget the work of water as it moves silt, clay, pebbles, and stone that have been caught in its channels and then moved downward toward its emptyings. Silt and clay are readily held in suspension even if the water is slow going. It requires rapid currents to move the heavier, coarser stones and pebbles. As these are carried along, their rough edges are worn off, their sides are scraped and scratched, and many particles are pulverized and ground — all contributing to soil making. To be sure, this soil will be deposited in lower regions, yet it is now soil, the same as that in the cultivated field or garden. The role that ice has played. — In the northern part of the United States we have a class of soils formed by giant masses of ice called glaciers, that moved in a southward course many, many centuries ago. Our ideas of the cause of this vast body of moving ice are not clear and we have only the evidence that once it was so. We are told that all the northern part of our country was covered with a frozen mass of ice and snow, and that for some reason this whole mass assumed a moving character, creeping over plain and stream, attacking every hill top and mountain range, and without further ado, concjuering them as if play mounds made by children's hands were the confront- ing power. As this huge mass moved onward in its course it gathered up huge rocks that once were free, quarried other giants from the bosoms of the mountains, and played with them as it went along — rolling them, forcing them together, dragging them, rubbing their rough faces until they were smooth (if perchance they were not com- pletely ground into powder) — until finally the rays of the THE SOIL MAKERS 15 more southern sun robbed the glacier of its power by melting- snow and ice, which freed, rushed on into river channels to be lost at last in the seas of the East and the South. Soils that were formed by this moving mass of ice are known as drift soils. Such soils vary greatly in composi- tion and in physical nature. The area formed by these glacier or drift soils is altogether lacking in uniformity, its surface is broken often abrupt, its elevation is some- times considerable, often but slight and its producing power is modified by the nature of the deposits. While it is true that these soils are fairly well supplied with necessary mineral constituents essential to plant growth JUST AFTER A FLOOD they are often deficient in organic matter — the source of nitrogen supply. Wind made soils. — While the wind is often most vigor- ous in its activity, it is a reasonably slow agent in soil making, when considered by its daily work ; it must be studied only in its aggregate in respect to all the geolog- 1 6 SOILS ical ages past. You will find the wind most actively at work in arid regions and in those sections where sand and dust most abound. A single experience in a wind storm must convince you of the power as well as of the quantity of earth that is moved throughout the world. Dust or particles of the earth are in the air at all times, and with every drop of rain, every flake of snow, and every movement in the air these particles are carried elsewhere than to the spot at which they were originally gathered up. You will find in some sections of our country huge mounds or drifts of sand that have been deposited by the constant and more vigorous action of the wind. CHAPTER II THE SOILS THAT LIVING THINGS HAVE MADE No one knows just when the first, plant came into the world, nor the kind : it was too far back in the dim ages of the past ; long before any history was ever written ; long even before man or bird or beast had yet appeared. We may be sure, however, that it was a very tiny plant, so small that the little roots did not need to go deep into the earth, for the soil was just beginning its growth. We may be safe even in saying that these early forms of plants had only the rock itself for their homes, and on this rock they established themselves, sending their small roots just the tiniest bit into the crevices and into the opened particles that had been loosed by air and water, by heat and cold. The beginning of plant growth. — But doubtless the earliest forms of plant life were aquatic in character: they lived in the water. Wc have learned of the solvent power of water. Many of the early stagnant pools became de- positories of water holding in solution the dissolved min- eral materials of the kinfl forming the rock structures. This was just the sort of food that these pioneer plants fancied, for they and all of their kind since have secured their feeding materials in this manner. As years and cen- turies passed, these beginning forms of plant life became stronger, more steady and some became quite venture- some, clinging to the rocks that held fast the waters of the pool ; and still others, flinging the experience of their parental tribes to the winds, ascended beyond the limits i8 SOILS of the pond, where flowing water was uncommon, there to become adjusted to their new homes and to their new environment — at last to be stationary in their rules of living. It is likely the first stationary forms found lodgment in the crevices of the rock, where perhaps had accumulated small quantities of soil that had been made long before by air and water working in unison. These plants, no doubt, set their fibrous roots firmly against the rock sur- faces and worked in their own way in securing the coveted elements locked in the storehouse of the rocks. Just as the ivy of to-day creeps over stone and brick, so did these first forms secure their food substances for their life and growth. But with this difiference : those were small, insignificant plants and of low order; the ivy has culture, good breeding and pedigree as its inheritance. Real soil was made and left. — You must not think SOIL BUILDERS AT WORK Leaves, roots stems and grass find their way back to the soil and enrich it THE SOILS THAT LIVING THINGS HAVE MADE I9 these pioneer plants lived forever. They grew old in time : they died. But at their death they left a valuable contribution to the world. They left the riches they had accumulated : the elements they had secured from the rocks, the substances of their growth, the wee beds of soil they had secured from their forefathers, from the donations of the wind, and from the gifts of air and moisture. With this wealth available, there was no longer so great a struggle. The decayed plant life in the crevices and the deteriorated rock afiforded better feeding grounds for plants, more soil for support, more food for the needs of maintenance and of growth. Consequently, this better- ing of material necessities afforded increased opportuni- ties for growth. A higher order of plants might now come. So the small struggling plants, through a long course of years, changed, now gradually, now suddenly, into stronger varieties and species — onward and upward in the scale, until the time when soil was present in abundance, when the higher plants, useful for food and raiment, might be secure and safe, thoroughly fitted and abundantly adapted to all the environmental conditions needed for their complete development and growth. The work of plants in soil building. — It follows, then, that every kind of plant is a soil builder. The decay of the plant at once produces a change in the texture of the soil-making material. It is this addition of the organic matter — the dead plant — that produces this constantly performed miracle : for as the plant decays in the soil, the particles of soil in contact with it likewise decay. In other words, soil rotting is soil making. Decay of any material in the soil — organic or not — favors and induces the breaking down of the various complex compounds forming the rock, or the raw or the untamed soils. 20 SOILS The addition of vegetable matter to the soil has assisted in soil making- from the time that plants came first to the planet; it has increased the efficiency of all other agencies ever since the early days ; and at the very present time it is the soil builder's best friend, — its decay is essential to the feeding of plants. The roots of plants have done their work in soil making. A great work it has been ! For they have gone down deep into the soil making tiny channels for air and water ; creeping into the crevices of rocks, they have continued their growth and their enlargement, in the end, breaking many rocks asunder, dis- lodging others from their beds, — exposing all to the disintegrating influences of air and moisture, of heat and cold. And roots — especially the small, fibrous ones — have a solvent action as well. The juice they exude at the tips, and the moisture with which they surround themselves, work a change in the soil particles between which they grow ; limestone or granite or feldspar or mica slowly but surely suc- cumbs to the deteriorating action of root life. Animals the modern soil makers. — Soil making ALFALFA ROOTS GO DEEP INTO was considerablv THE SOIL ^^.- w'jjjTj^, -^T THE SOILS THAT LIVING THINGS HAVE MADE 21 advanced when animals first made their appearance. But animals of all sorts have been potent workers in soil making, the higher animals largely by the manurial re- turn to the land and the lower forms through the manurial effect, but also in directly affecting the physical conforma- tion of earth. For does not the ant seek the earth for its home and shelter, to construct there its house of many rooms, with the many tunnels connecting the dwellings of the nation? What are these homes and these tunnels but underground traps for air and moisture — soil builders? Besides the work done in this direction, a tremendous quantity of earth is annually turned over and exposed to sunshine and rain, to heat and cold, to every influence concerned with soil making and soil improvement. Every sort of insect or animal that burrows into the soil, that opens it, or tunnels it, or loosens it, contributes not a little to soil making: the ant that builds there, the mole that tunnels, the prairie dog or hedgehog that bur- rows, the earthworm that glides and crawls, and even eats and digests — all are man's good friends in having had a hand in preparing the surface of the earth for the luxuri- ant growth of vegetable life. The task of the earthworm. — The task that has been the earthworm's is a most important one. So simple are these creatures, so faithful are they in their labors, so undemonstrative in their duties, we scarcely give them a thought save the time when we seek them for bait for our fishing traps. But the earthworm has for ages been busy opening the soil to air and water, and even more : it eats the raw soil underground and plows its way upwards and downwards, casting at the surface the unused por- tions of its eatings. In doing this, the muscular gizzard of the worm is ever busy rubbing and grinding stony 22 SOILS particles, mixing with these the organic matter taken into the body system ; with these go the secreted slime that has a dissolving effect — useful in making subsoil and un- tamed earthy constituents available as food for plants. As proof of the great good of these indefatigable workers, we have the evidence of Charles Darwin, who after long study and observation declared that in many parts of England as much as ten tons a day of dry earth annually were passed through the bodies of these common worms of the field. He also calculated that as much as ten inches of the upper surface of the soil passed through their bodies every fifty years. You can gather from this evi- dence what worthy workers these insignificant animals have been in preparing the earth for the habitation of man. The increased production of all products of the garden, of the orchard, and of the field has been due, in not a small measure, to these underground helpers and to these wonderful workers in soil making. CHAPTER III WHAT WE FIND IN SOILS Having come now to the point where soils are made, we may with all propriety consider their physical nature, and then the treasures they hold fast secured in their earthy storehouses. Not that soil making has ended, for this process goes on forever. Only this : a time has been reached in their development when, with the aid of tillage tools, the most productive and useful of plants might now be grown for the highest profit of man. Let us go out into the field itself. Of what is this soil made? was at one time the' first incjuiry. Naturally, it was said that soils were derived from the original rock formations. We have discussed already the agencies that have made our soils. No single one is responsible for yours or mine. That we possess these soils, there is no doubt. What brought them to us, what placed particular soils within the limits of our possessions, what influence or agency made them rough or level, good producing or poor producing, is not the problem now. Four kinds of soil materials. — Our present inquiry is in reference to their physical conformation, to their com- ponent parts, to the minerals composing them. These ma- terials are : sand, silt, clay, and humus or organic matter. All productive soils contain these materials, but not in the same proportions. There is a wide difference in the quantities of each in our many varieties of soil. A pre- ponderance of one of these materials over the normal 24 SOILS average gives rise to a grade distinguished by the name of the material there present in excess of that normal aver- age. Hence, we get names that stand for the particular type, as sand soils, where much sand is present ; clay soils, where much clay or silt is present; and humus soils, where much organic matter is present. Plants show preference for certain soils. — And there is a very great problem unfolded here, for the most of our field crops do not do equally well on each of these soil types. Not a little partiality is shown. While some crops are not so very choice of their soil homes, others are par- A CROP THAT IS HARD ON THE SOIL Tobacco is usually a profitable crop, but one that quickly exhausts the soil of its fertility ticularly mindful ; in fact, some, like the grape or tobacco plant, permit their fancy to extend even as far as the manufactured product. Size of soil particles. — It is due to the size of the parti- cles of which soils are made that we have our various classes of sand and silt and clay — rock descendants. When these particles are separated mechanically, we find WHAT WE FIND IN SOILS 25 that they can be classified into various groups, as follows : fine gravel, coarse sand, medium sand, fine sand, very fine sand, silt, fine silt and clay. To these components let us add humus, moisture, the sol- uble plant food elements, and we shall have the soils of our fields. The size of these particles and their mechanical ar- rangement have much to do in way of influencing soil productivity, of influencing heat, moisture, and plant food factors, of governing the type of soil that each crop fancies. Thus it is that a sand soil — where the coarser particles predominate — is a most favorable medium when reenforced with humus, in which certain crops, like the vegetables, are most at home. On the other hand, you will find the opposite extreme — where the finest soil grains predominate — most favorable to wheat and grass. In the first case — the sand type — water is freely received and as freely given to the subsoil, while with the clay type water enters with difiiculty but remains longer with its host. Between these extremes we find all sorts of modified types : light sand loams, sand loams, loams, clay loams, and heavy clay loams. We should add, also, humus to these combinations, for it must be understood that humus is positively a necessity for remunerative crops, regardless of type or of ancestry. What mechanical analysis shows. — To illustrate this point, let us take the meclianical analysis of barren sand soils : examples of the sand type that are found in many sections of the country — along the seashore, in the sand hills of the arid West, and throughout the desert regions. Using the plan now generally approved by soil investi- gators, we get the following — the average of ii barren sand soils : 26 SOILS BARREN SAND SOILS Material Per cent Organic Matter 3.75 Fine Gravel, 2-1 mm 1.40 Coarse Sand, 1-5 mm 27.92 Medium Sand, .5-. 25 mm 31.64 Fine Sand, .25-. i mm 17.48 Very Fine Sand, .1-.05 mm 12.66 Silt, .05-.01 mm 1.90 Fme Silt, .01-. 005 mm 0.86 Clay, .005-.0001 mm l.il The above percentages tell their own story : they show the classes in which these soil particles fall. In other words, as much as 84 per cent, of these barren soils is com- posed of sand. You can note readily the small percentage of silt, humus, and the clay components. Were plant food to be added, it would be lost as quickly as the water that falls as rain. Soils containing so high a per- centage of sand may be used for a limited number of crops, and then only when reen forced with or- ganic matter, chemical fertilizers, and water at frequent intervals (by irrigation, if possible). What special soil types show. — To develop this idea further, let us take the analyses of a few soils where certain standard crops grow to their fullest perfection, not for a single year, but for a time of sufficient duration to give these soils the right to the name of model examples of their type or class. SECTION OF THE SOIL SHOWING AIR SPACES AND PARTICLES WHAT WE FIND IN SOILS 27 MECHANICAL ANALYSES* OF TYPICAL AGRICULTURAL SOILS Material Corn Wheat Soil Grass Truck Barren Clay Bright To- bacco Heavy To- bacco Fine Gravel, 2-1 mm Coarse Sand, 1-5 mm Medium Sand, .$-.2$ mm 0.00 0.15 2.65 16.25 26.81 25-30 15.60 10.10 0.00 0.23 :.72 6.08 36.82 20.92 II. 21 2.3.78 0.00 0.08 0.13 0-53 10.94 19.02 4.67 5I-7S 0.00 0.30 6.04 49.63 32.29 6.24 1.93 2.80 0.00 0.00 0.29 1.27 8-93 20.16 16.72 50.02 3.09 7.16 21.74 22.92 16.76 13-17 8.24 4.80 1. 12 1.82 '•37 0.39 4-34 34.40 10.58 35-24 Fine Sand, .25-. i mm... Very Fine Sand, .1-.05 mm Fine Silt, .01-.005 mm.. Clay, .005-.0001 mm What does this table show? This — in a most striking way : that wheat soils, handled under certain conditions, possess a moderate quantity of their soil grains in the form of very fine sand, silt, fine silt, and clay ; that truck-crop soils possess but a small quantity of the finest grains, their characteristic lying in the great quantity of fine and \ery fine sand ; that the bright tobacco soils possess a limited quantity of the finer grains and most of the coarser grains, while the heavy tobacco soils are largely composed of the finer grains with a much lesser quantity of the coarser materials ; that the grass lands possess a very great quantity of clay and silt, but a relatively small amount of the coarser sand grains. In this table two types of grass lands are shown : the productive and the barren. The former is in good physi- cal condition, that is, its texture is in good form : the soil grains are reasonably well arranged, the humus content ♦ United States Department of Agriculture. 28 SOILS (while not given here) is probably sufficient to insure a healthy influence on plant growth. The barren clay here discussed is just as rich in plant food, but the soil grains — largely clay — are so arranged that the soil is puddled ; it offers extreme resistance to rain in its passage through, so that when plants are grown in this type of soil they quickly use the water about their roots — and much to their hurt. Wise farming plans will be in the line of drainage by tiles, thorough aeration by good tillage, and much organic matter supplied through stable manure and the legumes. How soil type affects plant growth. — The explana- tion of this is here : soils of a sandy nature maintain less moisture — only 5 to 7 per cent. — than those of a clay nature, and they are more open, the soil grains are larger, and the water resistance small. Hence, they dry out more quickly after rains and become sufficiently warm early in the spring and soon after rains, so that maturity is hastened. Grass lands, on the other hand, because of the large amount of small grains — silt and clay, — maintain from 18 to 20 per cent, of water, or nearly four times that of the truck lands. Consequently, these soils are colder by nature and therefore less active in maturing their crops. A longer time is needed, and this is favorable to the heavy leaf growth of grass, — a thing altogether undesirable for vegetable crops. Wheat lands, since the season of growth is long, are influenced favorably by this same fact of size and ar- rangement of the grains. It sometimes happens that seasons are extremely favor- able — sufficient water, Avarm weather in early fall and spring, and good covering of snow for winter protection — and wheat on the very stiff lands does moderately well, WHAT WE FIND IN SOILS 29 •**» CfflKMga 1^ - '3£ ^(^ ^ " '> *y^M m^^ B^ i 'i 1 ■ 1 1 1 ^^.iL;:^',>-' ^^^^ 1 1 ON TWO TYPES OF SOIL The upper picture shows well-grown apple trees in good loam soil, lower picture poor apple trees in light gravel loam. About 40 years is the age of the trees in both cases The 30 SOILS provided these stiff soils have been well aerated by tillage tools, for a time sufficient to put the soil in good physical condition. The best types of wheat land carry less moisture — from 12 to 15 per cent. — than the best grass types. Many secondary types are found. — \\hile the me- chanical analysis of soils recognizes but eight divisions, classified from the size of soil grains, the direct applica- tion to the field will show a great many more factors, since other considerations are in effect here, as the humus content, the arrangement of soil grains, the lay of the land, the ancestry of the soil, and the climatic help or hurt. The force of this is shown where humus is added to a soil. You find two soils alike in every way. Add humus to one — the texture is changed, the water-holding capac- ity is increased, the productivity is made greater. You have not changed the size of the soil grains, the basal principle of type remains the same. Another example : Take two sand soils, of the same basal type precisely, the components in both instances being the same. One is located in a section where the rainfall is abundant and where it is frequent. The other soil in a section where just the opposite extremes exist. It follows, without discussion, that other conditions being present — food, warmth, seed, and culture — the moist soil will generally produce a satisfactory crop and the dry soil an unremunerative crop. Mechanical analysis a help and guide. — We receive assistance when we know soil types, for we have a most helpful guide here at hand. But we have no posi- tive rule to follow in the selection of crops we shall grow. With more study, with more investigation, we may in future years predict with greater safety the behavior of WHAT WE FIND IN SOILS 3I soil under cultivation antl when j^iven certain crops that •seem to fancy these special types best. Bear these things in mind : 1. That sand areas, when properly rcenforced with humus, water, and plant food, are peculiarly adapted to all kinds of truck crops. 2. That early truck crops are more safely produced when a maxinuini of sand and a minimum (piantity of clay prevail. 3. That general or laLc truck crops are most safely pro- duced when the sand type carries the mininnim of the coarser and the maximum of the finer sand grades. CHOP ADAI'TATiON An apple orchard extending from loam to clay 4. That fruit growing calls for considerable clay as a part of the sand type. 5. That the best corn crops are produced where neither sand nor clay predominates — the silt materials producing the best results. 6. That the general grain crops are best suited when furnished a silt type of soil. 32 SOILS 7. That wheat is most at home in soils where fine silt and clay predominate. 8. That grass fancies most those soils that carry a high percentage of clay. 9. That potatoes prefer a sand type where medium sand prevails, where silt is present in a medium quantity, and where clay is present only in moderate quantities. 10. That with these special types must be included good tillage, humus, air, moisture, and plant food. Soil type standards. — It is out of the range of possi- bilities to give definite standards of soil type for specific crops : too many conditions prevail, such as previous treatment of the land, climate, plant food, humus content, soil drainage, tillage methods, etc. The following stand- ards are suggested in the light of known conditions — in a very general way : 1. Early truck and potatoes: Not more than 15 per cent, of water. As much as 60 per cent, of medium sand. Not more than 10 per cent, of clay. About 20 per cent, of silt. 2. Late truck and fruit: Not more than 20 per cent, of water. As much as 50 per cent, of medium and fine sand. Not more than 25 per cent, of clay. From 10 to 30 per cent, of silt. 3. Corn : An average of 20 per cent, of water. Not more than 50 per cent, of medium fine and very fine sand. Not more than 20 per cent, of clay. From 15 to 25 per cent, of silt. WHAT WE FIND IN SOILS 33 4. General grain : About 20 per cent, of water. From 40 to 60 per cent, of silt. From 20 to 30 per cent, of fine sand. From 15 to 20 per cent, of clay. 5. Wheat: From 15 to 20 per cent, of water. From 20 to 30 per cent, of clay. From 30 to 70 per cent, of fine silt. Not more than 15 per cent, of sand. 6. Grass: From 20 to 25 per cent, of water. From 40 to 70 per cent, of clay. From 20 to 30 per cent, of silt and fine silt. Not more than 10 per cent, of sand. CHAPTER IV CONCERNING THE TEXTURE OF THE SOIL Some soils are worked with ease, others with difficulty : plows are drawn with little resistance or with much, water enters freely or very slowly, plant food accumu- lates in quantities to meet the needs of plants, or so slowly pi^: ---■i -" --*^\''<^\:^^ OGCQQC / i^ ^t^ ^Y ^v I OqQOCXI 3 \ yv y\ -A. jAv J CQQOQC "j /^^""^^ /"^ /^'"^ /""x /"x wC