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Title: Report on the Agriculture Experiment Stations of the University of California (PH 4-16)(1890) Collection Type: Directories and Documents Collection Name: Pamphlets Catalog #: PH 4-16 Author: E.W. Hillgard Published: 1890 # of Pages: 211 Download PDF: User Login Required Download OCR Text: User Login Required

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APPENDIX. 163 Presentation and Interpretation of Soil Analyses. _ Aconvenient and uniform mode of presenting soil analyses is certainly important, since comparison is rendered extremely laborious by an indiscriminate arrangement of the items. In the scheme I have definitely adopted for use in this laboratory and in the publications of the:station, two points of view are observed. One is that the “insoluble residue” should be the first item to strike the eye, because it gives at a glance a certain insight into the general character of the soil—as sandy or clayey— which it is desirable to have in mind before passing to the inspection of the active ingredients. The other is, that in the arrangement of elements, instead of each one’s sweet will, the natural sequence of the electrolytic series should be followed; whereby, of the elements coming under consideration, potassium comes first and carbon last, the rest standing between in the well known order. The adoption of this simple and natural arrangement will obviate an immense amount of trouble and eye work in the extended comparisons, without which soil composition cannot be studied. Beneath the column of results of the general analysis, but separated so as to involve no misinterpretation, I place the results of the process of Grandeau; and last, the coefficient of absorption of aqueous vapor, which, with the ‘‘insoluble residue,” goes far to indicate the physical character of the soil. Interpretation of Analytical Results for Practical Purposes.—In forming a judgment regarding the practical import of the data resulting from a soil analysis, the simple question must be: “ WHAT DOES THE COMPARISON OF SUCH DATA WITH ACTUAL AGRICULTURAL PRACTICE TEACH US?” I have from the beginning of my soil studies—for thirty-five years past— kept this question constantly in view, and have systematically selected soils for detailed examination and analysis with that definite object. In stating hereinafter the conclusions reached, I premise that of course they can be proved only by a discussion of the data, most of which have been published and are accessible to any one desiring to review them. I freely admit that this is a laborious task; but no one who does not take the trouble to undertake it, or a corresponding course of investigation, can justly consider himself a competent witness in the premises, either for or against the views here presented. A comprehensive comparative inyestigation of virgin soils has not been undertaken outside of the United States, nor within them outside of the work conducted by Dr. D, D. Owen and the writer. The first broad statement that may be made is that in no case has any natural virgin soil * showing high plant-food percentages (by the analytical processes outlined above) been found otherwise than highly productive, under Javorable physical conditions. This being true, the practical value of soil analysis is thus far established: that it can teach the settler, @ priori, that Certain goils, new to him and to every one, are a safe investment. ut the reverse is not true, viz., that low plant-food percentages eer rily indicate low productiveness. That it cannot be true is evident rae e simple fact that heavy clay soils rich in plant food may adv age e diluted with arid sand, several times over, thereby sore peta oO diminishing their productiveness, because of improved physica ei ai. is fact is abundantly exemplified in the daily experience and practic , Javs of coal beds; nor to a soil that * Thi i ot, therefore, apply to the floor clays of coal t ss te a i a number of years; nor ) parley igh, “sted beneath eo ewe Schneider's dbjections to soil analysis (Am, Jour. guch 4s formed the basis 0 Clence), é