<L 
 
 JULY, 1875. 
 
 No. t7. 
 
 BULLETIN 
 
 OF THE 
 
 UNIVERSITY of CALIFORNIA 
 
 THESIS 
 
 ON UTILITY AND METHODS OP SOIL ANALYSIS. 
 BY L. S. BURCHAED, 
 
 Candidate for the Degree of Bachelor of Philosophy. 
 
 It is the object of Agriculture to supply to the world the 
 crude materials of what we eat and wear ; or, as more common- 
 ly known, Agriculture is the art which pertains to the cultiva- 
 tion of the soil, and to the rearing, feeding, and management 
 of live stock. There is no art more important than Agricul- 
 ture, nor noite which presents so many subjects of scientific 
 inquiry- and vital interest. And yet, but few subjects of simi- 
 lar moment, but what have received far more thorough and 
 scientific research. I fancy this is because agricultural science 
 is as yet in its infancy. Other sciences must first be developed 
 before this could make any satisfactory advancement: — Chem- 
 istry to give methods of analysis, and Geology to tell of soil 
 formation. Botany and Zoology must also make their contri- 
 butions, while years of experience, and practical testing of the- 
 ories should add their corroboratory testimony. 
 
 Agriculture takes rank among the highest sciences, but sin- 
 ularly enough, is but lightly appreciated, even by the class of 
 ’i who should give it the most attention. The farmers, as a 
 s, are not sufficiently informed, and among most of the edi- 
 ted, other subjects are given greater prominence, while 
 riculture receives only a casual consideration. The decay 
 old empires, and the decline in national vigor of the people 
 f those governments, clearly indicate that the farmer must 
 y 139 
 
 University Press, Berkeley 
 
2 
 
 BULLETIN OF THE 
 
 have regard to the manner in which he treats the soil from 
 whence comes his bread; while the statesman should not be 
 ignoranf of one of the grandest elements of national prosperity, 
 viz : soil fertility. 
 
 The farmers of every age and country have first planted one 
 crop after another, without any regard for the soil’s treatment. 
 And quite naturally enough, for they did not know what com- 
 posed the soil or the plants growing upon it. They did not 
 know how to care for their land, and consequently it soon be- 
 gan to exhibit signs of infertility. The difficulties they could 
 not remedy, but other countries were fertile and to them many 
 of the people emigrated. Men, however, cannot easily migrate, 
 nor are such migrations conducive to national prosperity; hence 
 the leading men of the nation, perceiving the evil, began to 
 give attention to the soil’s cultivation. Among the Hebrews 
 the land had its periods of rest. Other and later generations 
 thought of adding something to the soil. But what should be 
 added, and should the same fertilizer be added to all soils? 
 
 China and Japan solved the problem quite satisfactorily for 
 themselves. But they shut themselves up from the rest of 
 mankind, and we Indo-Europeans remained in ignorance as 
 the rolling centuries passed along. 
 
 A host of fertilizers have been tried and many of them found 
 to improve the soil’s fertility. But as the same fertilizer would 
 not answer on different soils, it was with much reason presum- 
 ed, that a chemical analysis of the soil and of its vegetation, 
 and of the substances to be added would give all the required 
 information for maintaining the soil’s productiveness. 
 
 If we knew what to add to the soil, there seemed to be no 
 question, but that the soil which yielded one bale of cotton to 
 the acre, and which now yields but one-fourth of a bale, would 
 yield, by this new and really marked advance in agricultural 
 knowledge, from two to three bales per acre. Our expecta- 
 tions were high, but our two or three bales of cotton to the acre 
 were rarely realized. What was the difficulty? We certainly 
 are in possession of an important factor in crop culture. 
 
 Not every analysis was correct, and no thought was tak 
 as to whether the important soil constituents were in an a" 
 able or unavailable condition. A mechanical analysis mus^ 
 made in addition to the chemical. The physical properties 
 the soil, whether open, light, porous, heavy, dark, deep, or sin 
 low; its dryness, warmth, division; whether in a rainy or rai. 
 
 140 
 
UNIVERSITY OF CALIFORNIA. 
 
 3 
 
 less region; climate, high or low land; kinds of crops raised 
 on the soils; how long under cultivation; drainage, etc.; all 
 these factors, and more, are to he taken into consideration. 
 Hence a single chemical analysis, while giving valuable infor- 
 mation to the agriculturist, is only one of .many things which 
 determine the value of the soil and its adaptation to particular 
 crops. 
 
 This fact, however, is generally lost sight of ; many giving 
 undue prominence to the soil’s chemical analysis, while others, 
 among the number Professor Johnson, consider it as compara- r 
 tively useless, and urge such objections as the following: Two 
 soils may be of quite similar composition, and yet be very un- 
 like in fertility. The least productive one, is so because of 
 some physical condition: as a want of under-drainage, lack of 
 rain, depth of soil, etc. 
 
 To correct the soil’s physical defects often improves at once 
 its chemical condition. A correct chemical analysis of the soil 
 requires much time and is expensive; and when made, one is 
 not able to tell whether his soil is just now fertile or barren. 
 Some soils, naturally sterile, by adding four hundred pounds 
 of guano to the acre, manifest a wonderful productiveness. 
 The analysis represents but a small part of the field, and does 
 not indicate the soil’s openness, heaviness, etc. Johnson sug- 
 gests, instead of chemical analysis, experiments on different 
 plots of land with those fertilizers most likely to cause the par- 
 ticular soil to become fertile. These are strong objections 
 against the chemical analyses of soils, if such analyses were 
 one’s only source of information respecting the soil’s composi- 
 tion, condition, and value. But, when we know that chemical 
 analysis is only one factor of our knowledge of the soil and its 
 intelligent cultivation, the above objections appear a little 
 specious, and thus lose most of their force. Is it not rational 
 to suppose that a soil rich in certain ingredients would be bet- 
 ter adapted to a particular class of plants demanding those par- 
 ticular ingredients, than it would be for any other class of 
 plants ? To determine by experiment alone what a soil is good 
 for, is, to say the least, a lengthy, tedious, and costly process. 
 In the case of *• poison soils,” which to all appearances are fer- 
 tile, and yet contain substances which are injurious to crops, 
 experiment is almost folly. Take this example: some soil of 
 Bae’s Island, Beaufort county, South Carolina, appeared to be 
 good soil, but would not grow cotton. The planters did not 
 
 145 
 
4 
 
 BULLETIN OF THE 
 
 know how to obviate the difficulty. They had tried Professor 
 Johnson’s blind experiments to their entire satisfaction. The 
 soil was analyzed, and found to contain some proto-sulphate of 
 iron, a substance which is poisonous to plants. The chemist 
 gave the remedy also, viz: under-drainage, aeration, and the 
 addition of some lime. 
 
 Comparative Chemical Analysis of Soils not only tells one 
 what is the soil’s composition, but also the ratio of its plant in- 
 gredients to each other and to those found in other soils. 
 
 If a soil is found to be rich in the nutritive plant ingredients, 
 viz: K"Q, P 2 0 5 , CaO, N and C, we know what crops would, in all 
 probability, grow most successfully upon it; and if deficient in 
 any one of these elements of plant foods, what particular fer- 
 tilizer could be most advantageously applied. For example : 
 in a soil containing a small proportion of lime and sulphuric 
 acid, let leguminous plants as peas, beans, etc., be planted; this 
 soil would soon give out; but, by the addition of an occasional 
 coat of gypsum, its fertility is maintained. Again, if in a soil, 
 which is poor in phosphates, cereals are planted, we know it 
 will soon become exhausted, and that our remedy is to add to 
 the soil super-phosphates. 
 
 These remedies are not infallible ones by any means, and the 
 soil which is rich in K 2 0, CaO, P 2 0 5 , N. and C., may have these 
 compounds in an unavailable form; but we have much light 
 thrown upon the soil’s permanent value, and probable adapta- 
 tion. A soil which is rich in this plant food, will undoubtedly 
 contain much of it in an available form. 
 
 By the Mechanical Analysis, and the observations and in- 
 quiries made in connection with it, we obtain very much addi- 
 tional knowledge of the soils condition and value. A soil com- 
 posed mostly of fine silicious silts, and a small per centage of 
 clay, we know is very heavy, will clog to the plough, and cakes 
 when drying. Coarse ingredients make the soil more porous 
 and light. We find that the clay in the soils is the richest in 
 mineral ingredients, holds the most moisture, ammonia and 
 other soluble salts, and its insoluble residue is comparatively 
 small. A soil of coarse sand is infertile, subject to drought, 
 and will not allow plant food to accumulate. A soil of fine 
 sand with some clay is a good one, especially if derived frorft eas- 
 ily decomposed rocks. 
 
 Thus we find, that a chemical and physical analysis of the 
 soils lies at the foundation of a proper estimate of its capacity, 
 
 142 
 
UNIVERSITY OF CALIFORNIA. 
 
 5 
 
 adaptation, and future value. The soil contains the ances- 
 tral remains vof past ages, and is the great store-house from 
 which we draw most of life’s supplies; consequently, a scientific 
 inquiry into its composition and value, is a matter of prime im- 
 portance: not alone to the farmer, but to the statesman also. 
 Such an inquiry tells us what is in the soil, in what condition, 
 the physical structure of the soil, what crops are best to plant, 
 and what fertilizers to add. Let us- now consider the methods 
 of conducting this inquiry. 
 
 SELECTING SPECIMENS. 
 
 Before commencing the analysis, and at the place of gather- 
 ing the soil, it is necessary to make note of a few important par- 
 ticulars. 1st. As to the locality; whether hillside or valley 
 land, how near to mountains — in a word, something of the top- 
 ography of that section. 2d. Underlying geological formation, 
 as well as that from which the soil has been derived. 3d. Depth 
 of soil, surface, and the obvious physical characteristics of the 
 soil. 4th. Local vegetation, natural and cultivated; how long 
 under cultivation, and what crops grown; whether manured, 
 and what manures used; color of soil taken; average rainfall;, 
 and any other points of special importance pertaining to that 
 particular locality. To the above information is added the 
 farmer’s experience in cultivation of that particular soil. 
 
 Sub-soil is preferably taken for analysis, because in surface 
 soils the organic ingredients materially interfere with the opera- 
 tion of the analysis, as well as with the interpretation of its results. 
 The investigation of sub-soils is better calculated to furnish 
 reliable indications of the agricultural peculiarities of extended 
 regions than that of surface soils, which are more liable to local va- 
 riations, and usually differ from the corresponding subsoils, in 
 about the same general points. The surface soil generally has 
 the largest amount of immediately available plant ingredients, 
 while the sub-soil has the largest supplies for future use. 
 The following table from Prof. Hilgard’s Keport on the Agri- 
 culture of Mississippi, further illustrates their chemical differ- 
 ence. 
 
 143 
 
6 
 
 BULLETIN OF THE 
 
 Analysis of Upland Soil and Sub-soil from Claiborne County , 
 
 Mississippi. 
 
 Surface soil. 
 Sub-soil .... 
 
 Insolu. 
 
 part. 
 
 87.6 
 
 79.5 
 
 K 2 0. 
 
 .458 
 
 .741 
 
 Na 2 0. 
 
 .124 
 
 .248 
 
 CaO. 
 
 .244 
 
 .238 
 
 MgO. 
 
 .545 
 
 .830' 
 
 Mn 3 0 4 . 
 
 .205 
 
 .346 
 
 
 Surface soil . 
 Sub-soil .... 
 
 Fe 2 0 3 . 
 
 3.231 
 
 5.634 
 
 A1 2 0 3 . 
 
 4.84 
 
 8.849 
 
 PA. 
 
 .105 
 
 .092 
 
 so 3 . 
 
 .028 
 
 trace. 
 
 Volatile 
 
 matter. 
 
 3.073 
 
 3.476 
 
 
 The specimen for analysis should, whenever possible, be 'of 
 virgin soil, taken from some one or several spots, carefully se- 
 lected as correctly representing the average character, undis- 
 turbed by local accidents, such as cultivation, roads, gullies, 
 cattle, etc. Make vertical cuts showing distinctly the depth of 
 surface soil and sub-soil, and of each take a specimen of at 
 least 10 pounds, after thoroughly breaking the clods and mix- 
 ing, with a spade, on a cloth spread on the ground, the pile 
 thrown out of each — the larger the better. A pound or two of 
 the specimen is then air-dried, carefully triturated in a porcelain 
 mortar with a wooden pestle, and sifted through a sieve 
 whose meshes are .8 mm (=.03) diameter. We now have 
 the dry “ fine earth from this point the two analyses 
 branch. 
 
 MECHANICAL ANALYSIS. 
 
 We shall first take up the mechanical or silt anal- 
 ysis. Take 15-20 grammes of the steam-dried “fine earth” 
 and boil for twenty-four to thirty hours in distilled water. 
 This is done to completely disintegrate the soil particles. 
 The second process is to separate the clay from the silt 
 and sand, as the presence of clay in the elutriator would ma- 
 terially interfere with the proper separation of the sediments. 
 The clay is thus separated : thoroughly stir the boiled liquid and 
 sediments in a quantity of distilled water, and allow to settle 
 for such a length of time as will allow sediments of .25 mm hy- 
 draulic value to subside; the process is repeated with smaller 
 quantities of fresh water until no sensible turbidity remains 
 after allowing due time for subsidence. As some fine silt sedi- 
 ment is poured out with the clay water, and this separation must 
 be repeated, unite the clay waters (4-8 litres), stir them up, allow 
 to settle for eight minutes if the liquid stands at the height of 
 
 144 
 
UNIVERSITY OF CALIFORNIA. 
 
 7 
 
 200 mm and then pour off the clay water. The sediments are now 
 ready for the elntriator. The clay water, however, still contains 
 silt of <0.25 mm h. v. which is separated by putting the clay water 
 in a cylindrical vessel to the height of 200 mm , allowing to sub- 
 side for twenty-four hours, then decanting the clay water and 
 kneading the silt with a rubber pestle. Fresh distilled water 
 is again added, the whole agitated and allowed to subside for 
 another twenty-four hours. Kepeat the operation until the 
 decanted liquid is clear, or fails to become so by the addition 
 of salt water. 
 
 The clay is precipitated from the clay water by adding 50 c. c. 
 of saturated brine to each litre of clay water. 
 
 Collect the precipitate on a weighed filter, wash with weak 
 brine, dry at 100°C and weigh. The salt in the clay is then washed 
 out with (NH 4 ) 2 C1, and the weight of the salt in the filtrate is 
 determined by Evaporation, ignition and weighing. Knowing 
 this weight we can easily determine that of the clay. The 
 amount of clay in the purest natural clays rarely reaches 75 
 per cent; 40 — 47 in the heaviest clay soils, and 10 — 20 in 
 ordinary loams. 
 
 Separation of the silt and sand sediments . 
 
 These sediments are transferred to the Elutriator, a cylindri- 
 cal vessel through which water is made to pass, carrying along 
 with it sediments corresponding' to the different velocities of 
 water passing through the tube. 
 
 The different velocities of the water are determined by means 
 of the graduated arc along which the long arm of the stop-cock 
 moves. 
 
 The cylindrical vessel and churner at its base are designed to 
 prevent the aggregation of flocculent masses of sediment which 
 tend to form in the ascending current. 
 
 Several other devices intended to accomplish the same result 
 have been resorted to by different persons, as Nobel’s appara- 
 tus with its four vessels of ever varying capacity, slope of sides 
 and variable head of pressure. This apparatus gives five differ- 
 ent sediments of a character not approaching uniformity. In 
 the same instrument with the same kind of soil, one gets widely 
 different results. 
 
 Yet this apparatus is the one recommended by Caldwell in 
 his work on Agricultural Chemistry, and the one used by Emil 
 Wolff of Germany. 
 
 141 
 
8 
 
 BULLETIN OF THE 
 
 Schultze’s apparatus as modified by Fresenius, is a tall, con- 
 ical champagne glass with an adjustable stream of water de- 
 scending through a tube in the axis. This apparatus is better 
 than Nobel’s but has the defect that heavy sediments collect 
 around the mouth of the tube, thus affecting the velocity of the 
 stream, and allowing a portion of the fine sediments to escape 
 the elutriating action. Dietrich’s apparatus is a device for car- 
 rying the sediments in a stream of water, under constant pres- 
 sure, flowing through four tubes of different sizes and inclined 
 at different angles. This apparatus will not give like results 
 with similar soils. The later and more improved methods of 
 Mueller and Schoene give more satisfactory results but have 
 the same defect in common with all the others; viz: no agita- 
 tion of the sediments by outside power. Prof. Hilgard uses a 
 Mariotte bottle (10 gal.) to get a constant pressure for the dif- 
 ferent velocities of water; a cylindrical vessel through which 
 the sediments are borne; and a rotary churn by which the sedi- 
 ments are constantly agitated. 
 
 From this digression in regard to the various methods em- 
 ployed in making silt analyses, we come back to our mixed sed- 
 iments. These are cautiously put into the elutriator, and the 
 current adjusted to the lowest velocity to be used; the flow con- 
 tinuing until all sediment of that hydraulic value has passed off, 
 when the higher velocities are successively turned on. 
 
 Decant and filter the water from the respective sediments, 
 except those below .25 awa -, which after subsiding to 25 — 
 50 c. c. m. are evaporated in a platinum crucible. The sedi- 
 ments are dried at 100°C and weighed. 
 
 Character of the Sediments. 
 
 As a standard of size measurement we take the round 
 quartz grain of tFo m. m. diameter. None of the sediments 
 are entirely free from particles of the one next below, owing 
 both to the progressive disintegration of conglomerated parti- 
 cles by the stirrer, and to the inevitable formation of the floc- 
 culent aggregates of the finer sediments. 
 
 By measuring the sediments and comparing them with our 
 standard we have the following; 
 
 146 
 
UNIVERSITY OF CALIFORNIA. 
 
 9 
 
 Table of diameters and hydraulic values of the different Sediments. 
 
 Name. Diameters. Velocity per second or 
 
 Hydraulic value. 
 
 1, Coarse Grits . . 1 
 
 — 3 
 
 mm. 
 
 ? 
 
 
 2, Finer Grits. . . .5 
 
 — 1 
 
 do. 
 
 ? 
 
 
 3, Coarse Sand. .80 
 
 -90(rb) 
 
 do. 
 
 64 
 
 mm. 
 
 4, Medium Sand. 50 
 
 —55 “ 
 
 do. 
 
 32 
 
 do. 
 
 5, Fine Sand. . . .25 
 
 —30 “ 
 
 do. 
 
 16 
 
 do. 
 
 6, Finest Sand . . 20 
 
 —22 “ 
 
 do. 
 
 8 
 
 do. 
 
 7, Dust Sand. . . .12 
 
 —14 “ 
 
 do. 
 
 4 
 
 do. 
 
 8, Coarsest Silt . . 9 
 
 — 9 " 
 
 do. 
 
 2 
 
 do. 
 
 9, Coarse Silt. . . 6 
 
 — 7 “ 
 
 do. 
 
 1 
 
 do. 
 
 10, Medium Silt. . 4 
 
 — 5 “ 
 
 do. 
 
 .5 
 
 do. 
 
 11, Fine Silt 2.5— 3 “ 
 
 do. 
 
 .25 
 
 do. 
 
 12, Finest Silt 
 
 1— 2 “ 
 
 do. 
 
 <.25 
 
 do. 
 
 13, Clay 
 
 ? 
 
 
 <.0023 
 
 do. 
 
 Strictly speaking, none of the sediments actually correspond 
 to the velocities calculated from the cross section of the tube 
 and the water delivered in a given time, but to higher ones. 
 Still these sediments show at once even to the naked eye, that 
 the assorting process has been quite successful, and that the 
 prominent characteristics of soils in these respects may thus lie 
 determined and exhibited to the eye with a very satisfactory 
 degree of accuracy. 
 
 I here recall to mind the object of silt analysis: It is to 
 convey to any intelligent mind, anywhere in the world a defin- 
 ite idea of the agricultural qualities of the soil; of its tillability, 
 perviousness, and behaviour in wet and dry seasons; its liability 
 to washing etc. ; which will be accomplished as soon as all the 
 physical coefficients belonging to each of these sediments shall 
 be understood. 
 
 CHEMICAL ANALYSIS. 
 
 Our attention shall now be directed to the chemical analysis. 
 In this part of my analysis, as in the mechanical, I have 
 followed the method employed by Prof. Hilgard: 
 
 First: To determine the Hygroscopic Moisture of the soil, a 
 quantity of the fine dry earth is exposed in a thin layer to a 
 saturated atmosphere for twelve hours; weigh and dry at 200°C. 
 and weigh again. The difference in weight gives the percent- 
 age of hygroscopic moisture. The object of this determin- 
 ation is to ascertain the soil’s power to resist drought. 
 
 147 
 
 z 
 
10 
 
 BULLETIN OF THE 
 
 For the general analysis, take 2 to 2.5 grammes of 
 the dry soil, and digest in HC1 of strength 1.115 over 
 a water bath for five days; evaporate, moisten with HC1, 
 redissolve in distilled water, and filter. The filtrate con- 
 tains the substances for which we are looking, viz: K 2 0, Na 2 0, 
 CaO, MgO, Fe 2 0 3 A1 2 0 3 and S0 3 . The author of an article in 
 the New American Cyclopedia and Dr. McMurtrie in Agricul- 
 tural report for 1873 (also Mr. Grandeau) object to the use of 
 HC1 to dissolve out the available plant ingredients, saying that 
 we go farther than the forces of nature. They would digest the 
 soil with (NH 4 ) 2 C0 3 . 
 
 NH 4 and C0 2 act to set free the alkalies in soils. Lime 
 has a similar property. In the soil we find humic, ulmic, 
 crenic, apocrenic, sulphuric, and oxalic acids. Different plants 
 have different acids to exert their solvent action on the soil in- 
 gredients. So one finds that (NH 4 ) 2 C0 3 is only one of several 
 soil solvents — a strong one to be sure, yet it does not give us in 
 solution all the available plant ingredients of the soil. 
 HC1 does, being the best single acid for dissolving inorganic 
 substances. Should one get much more of the plant ingredi- 
 ents by using HC1 than is at once available to the plant, he is 
 sajp, at least for comparative analyses, and also knows what may 
 be useful in future to the plant. 
 
 So far as we know at this time, no one solvent is adequate to 
 make the distinction between available and unavailable soil in- 
 gredients for all crops. The comparison of soils of similar ori- 
 gin, analyzed in a similar manner, is the best we can do at pre- 
 sent. When we thus ascertain that a soil is rich in nutritive 
 ingredients, we know that for durability, it is preferable to oth- 
 ers of its kind containing a smaller proportion of the same in- 
 gredients. 
 
 In the insoluble residue the soluble silica is determined by 
 boiling in Na 2 C0 3 . The Fe 2 0 3 and A1 2 0 3 are precipitated accord- 
 ing to Rose’s method of boiling with (NH 4 )HO and (NH 4 ) Cl. 
 The mixed precipitate is treated with KHO. Precitatethe CaO 
 by (NH 4 ) 2 0 4 and destroy the ammoniacal salts by Lawrence 
 Smith’s method with aqua regia : and the residue is converted 
 into nitrates, from which S0 3 is precipitated by Ba(N0 3 ) 2 The 
 alkalies are then separated by treatment with oxalic acid; ignite, 
 dissolve in water and filter. In the residue, Ba, Mn, and Mg 
 are separated as usual. The alkaline carbonates are converted 
 into chlorides and K precipitated by PtCl 4 ; evaporate and dis- 
 
 148 
 
UNIVERSITY OF CALIFORNIA. 
 
 11 
 
 solve the Na 2 salt by the alcohol-ether mixture, filter, ignite, and 
 weigh. The Na 2 0 is determined by difference. 
 
 Phosphoric acid determination . 
 
 Take 3 to 3.5 grms. of dry fine earth, ignite and digest for five 
 days in HN0 3 over a water bath, evaporate to dryness, moisten 
 with HN0 3 , add water and filter; precipitate by ammonium mol- 
 ybdate, filter and dissolve by (NH 4 )HO ; reprecipitate by MgSO 4 , 
 dry, ignite and weigh as Mg 2 P 2 0 7 ,from which the P 2 0 5 is easily 
 calculated. 
 
 The usual mineral ingredients in the soil are, K, Na, Ca, 
 Mg, Mn, Fe, A1 and Si, as metallic elements; and P, F, C, S, 
 and Cl as non-me tallies. Preeminently the most important of 
 these, and the ones requiring replacement in future by fertilizers, 
 are K 2 0, CaO, P 2 0 5 ,N and C. 
 
 The phosphates are found chiefly in the seeds, especially of 
 cereals; while root crops draw more upon the K 2 0 of the soil, 
 and leguminous plants draw largely upon N, and the phos- 
 phates. CaO and MgO are preeminently stem ingredients. Na, 
 Si, Mn, Mg, Fe, S, and Cl are generally found in sufficient quan- 
 tities, and need no replacement. N and C are contained in hu- 
 mus, which may be supplied by green-manuring. Ca, by adding 
 lime, which <also sets free unavailable K 2 0 and other alkaiies. 
 P 2 0 5 is supplied, when needed, by bone phosphates. 
 
 The grand law of soil preservation is to return to the soil as far 
 as possible all that you take from it. Other expedients may be 
 resorted to with great advantage, and in some instances are 
 absolutely necessary to insure a good crop; as subsoiling, green- 
 manuring, underdrainage, mulching, and rotation of crops. 
 
 Briefly adverting to my analysis, I give below a succint state- 
 ment of its 
 
 RESULTS. 
 
 First : observations made at the place of procuring soil speci- 
 men. The sample which I selected for analysis, was some sub- 
 soil near the propagating house.* I find it to be a hillside soil 
 of adobe character — surface soil one foot deep — subsoil is of 
 light, yellow color, and has the appearance of containing much 
 clay; natural growth — oaks. The soil is derived from the de- 
 composition of coarse and soft clayey sandstone, together with 
 washings from the hill. 
 
 Second, I give in a tabular form the results of the mechanical 
 and chemical analyses. 
 
 *0n the University Grounds. 
 
12 
 
 BULLETIN OF THE 
 
 Table of Mechanical Analysis. 
 
 GRAMMES. 
 
 Amount taken for Analysis 19.34 
 
 PER CENT. 
 
 (Hygroscopic Moisture 9.07) 
 
 Clay 24.7 
 
 Sediment of <0.25 m. m., i. e. finest silt .24.5 
 
 ££ .25 m. m. — 2 m.m., i. e. remaining silt. 11.0 
 
 ££ 4 m. m. i. e. Dust Sand 6.3 
 
 t£ 8 ££ <c Finest sand 5.3 
 
 ££ 16 “ ££ Fine sand. . 6.2 
 
 ££ 24 ££ ££ Medium sand 6.0 
 
 ££ >24 ££ ££ Coarse and medium sand. . 8.9 
 
 Table of Chemical Analysis. 
 
 GRAMMES- 
 
 Amount taken for Analysis 2.467 
 
 PER CENT.. 
 
 Insoluble Residue 80.79 
 
 (Si0 2 soluble 5.01) 
 
 K 2 0 65 
 
 Na 2 0 05 
 
 CaO 35 
 
 ]#gO 50 
 
 Mn 3 0 4 22 
 
 Fe 2 0 3 5.50 
 
 A1 2 0 3 (By diff.) 6.43 
 
 P 2 0 5 09 
 
 S0 3 .10 
 
 Water and volatile matter 5.32 
 
 My analysis may simply be regarded as a preliminary one. 
 The first analysis is generally considered as one giving valuable 
 suggestions only, to be made use of in a second analysis of the 
 soil, and also indicating much real information as to the soil's 
 chemical and physical composition. 
 
 I could not have hoped to have obtained more than ap- 
 proximate results; since in the mechanical analysis, the 
 elutriator which I used is the one designed for coarse sed- 
 iments only, and in consequence of its conical form, it ad- 
 mits of the formation of return currents, which cause the 
 single grains of sediment to aggregate into heavy masses. 
 
 And in the chemical analysis, the chemicals which I used 
 
 150 
 
UNIVERSITY OF CALIFORNIA. 
 
 13 
 
 were not as pure as they should have been, nor was I as suc- 
 cessful in the use of them as I might have desired. However, 
 uniting the observations made at the locality where I obtained 
 my specimen, with the results of the physical and chemical anal- 
 yses, one may arrive at satisfactory conclusions for an approxi- 
 mate analysis. 
 
 Making use of my results, then, as the basis of my observa- 
 tions in reference to this soil, I should say, from the chemical 
 analysis, that the soil contains, as most clay soils do, a large 
 amount of K 2 0, but a small amount of lime; which indicates 
 that much of the K is in an unavailable form. Hence in all pro- 
 bability the productiveness would be greatly increased by the 
 application of lime. 
 
 The consideration of the mechanical analysis shows, more- 
 over that even a small addition of lime would be of advantage 
 in improving the tillable qualities of this soil, since the clay 
 percentage is not very large. Hence in this double point of 
 view, the application of lime is indicated as likely to be of espec- 
 ial advantage to this soil. 
 
 We may confidently say that by properly combining th^exa- 
 mination of the physical and chemical properties of soil and 
 clays we shall be able to fulfill in great measure the high expecta- 
 tions entertained in the early days of agricultural chemistry. 
 
 As furnishing knowledge of the soil, soil analysis is of prime 
 importance and is at the foundation of all agricultural opera- 
 tions. One cannot have a satisfactory or sufficient knowledge 
 of his soil until he has had it carefully analyzed. Uniting the 
 information so derived with that obtained by his own or other’s 
 observations, experiments, and experiences, the farmer can then, 
 and only then, intelligently cultivate his soil. 
 
 151