Collection: Directories and Documents > Pamphlets

About This Item:

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

Printed or handwritten: All printed text Date Scanned: 2024-10-31 16:19:15 Scanned By: Shelby Figueroa Scanning Equipment: CZUR Book Scanner OCR Software Version #: tesseract 5.4.1 Item Sourced From: JPGs First Created: 2025-03-17 05:48:55 Last Updated: 2025-03-17 05:48:55

Original Held At: Searls Historical Library Location: 161 Nevada City Hwy, Nevada City, CA 95959

Page: of 211  

144 UNIVERSITY OF CALIFORNIA. under varying temperatures; and it is readily intelligible that in i depths of an alluvial deposit the preponderance of carbonic acid should, as in the case of the station well water, give rise to a corresponding preponderance of sodium carbonate, while gypsum is deposited. Hence the importance, if not necessity, of a liberal use of gypsum where such waters are employed in irrigation, in order that under the influence of surface exposure the reverse action may ensue and the noxious carbonate be shee urably transformed into bland sulphate. This reverse action has, as wil be noted, occurred to a greater or less extent in the surface soils of the lake alluvium; while it became complete farther away, in the Smyrna een eG Kern County, where, as stated above, the alkali is throughout ‘white.It is thus apparent that so far as the efficacy of the use of gypsum against alkali is concerned, each region will have to determine for itself whether or not its alkali is of the black or white type; and as this can be generally readily ascertained by a simple inspection of puddles on alkali ground— whether or not tinted by the dissolution of the vegetable mold into an inky liquid, leaving black rings on evaporation—no one need be long in doubt on that point. Wherever the black tint appears, dressings of land plaster, ranging from two hundred to five hundred pounds per acre, will usually effect the change from “black” to “white,” after one or two irrigations followed by cultivation; preventing the killing of seeds in the ground as well as the dwindling of seedlings after sprouting, and greatly improving the tillage of the heavier soils. Thereafter, the chief measure toward the prevention of the rise of the salts to the surface is whatever tends to prevent evaporation from the land surface; and therefore particularly the main tenance of deep and thorough tilth, and the avoidance of the formation of any surface crusts. These means, together with a proper choice of crops and mode of culture, will serve to maintain good production in most cases until the radical cure by drainage alongside of irrigation shall be justified by the increased value of the land. Value of Gypsum (Land Plaster) as a Fertilizer. Since the favorable effects of the use of gypsum on soils tainted with “black alkali” have become known, farmers, as well as others (more pat ticularly those interested in the development of mines of this material), have frequently applied for information as to the value of land plaster as a general fertilizer. To forestall as much as possible the necessity of continuing to answer such queries individually, it is best to present in this place a general statement in the premises. Since gypsum can supply to the goil only two ingredients taken up by plants as nutrients, it cannot have any direct fertilizing effect save in cases where one or both of these two ingredients—lime and sulphuric acid—are deficient. But of over twelve hundred California soils now in the University collection, probably not over a dozen would be at present benefited by an additional supply of lime; that ingredient being, from climatic causes, almost ede abundant in the soils of arid climates. As to sulphuric acid, it has not been found deficient in any soilexamined; and from causes parallel to those tending to render lime abundant, it is not likely to be required as a fertilizer anywhere in California within a century. Gypsum is, therefore, a special fertilizer only, and is not to be compared to such fundamental fertilizers as the phosphates, the nitrates, and, in their proper place, the potash salts, which serve to replace directly what the crops with-