SULFUR FERTILIZATION IN CALIFORNIA AND SOME RELATED FACTORS
- 1 July 1950
- journal article
- research article
- Published by Wolters Kluwer Health in Soil Science
- Vol. 70 (1) , 43-54
- https://doi.org/10.1097/00010694-195007000-00006
Abstract
S and gypsum fertilization of irrigated alfalfa in California starting about 30 yrs. ago resulted in substantial increases, even to a doubling of the yield, in all counties; in other areas, similar fertilization produced no increases. More recently the very desirable range legume., bur clover (Medicago hispida). as well as other dry-land legumes, has been increased materially from S and gypsum applns. The legume growth enhanced by S fertilization the 1st yr. has often augmented the growth of the following non-legumes the 2d yr. Elemental S in general gave yield increases about equal to those from gypsum-S except when the element was applied to the soil surface in areas or in seasons of limited precipitation falling only in the colder months. Under these conditions the gypsum plots outyielded the S plots the 1st yr. The S in many soils is chiefly in the organic matter. The content of S and the rate of decay determine the rate of supply of available S (generally as sulfate) from this source. In the presence of easily decomposable organic matter, such as cereal straws and starches, soil organisms may compete with higher plants for the small amt. of sulfate available in S-deficient soils. Unfertilized soils may contain much less total S than P, but for some crops the S requirements may be greater than the P requirements. Correlations between soil series and S deficiencies may be upset by the usually unnoticed sources of S from outside the soil it-self; namely, unnoticed S-containing gases arising from industry into the air, unnoticed sulfate-S in the irrigation water, unnoticed S in the fertilizers usually applied, and unnoticed S in materials applied to control pests.Keywords
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