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The Fixation of Potash by a Kaolinitic and a Montmorillonitic Soil
Author(s) -
Hoover C. Dale
Publication year - 1945
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1945.036159950009000c0010x
Subject(s) - potash , agricultural experiment station , citation , library science , soil water , history , archaeology , agriculture , geology , computer science , soil science , agronomy , fertilizer , biology
MANY soils in the State of Mississippi are markedly 'deficient in potash, while practically all of them, except some of the black land prairie and most of the central and western part of the YazooMississippi Delta, will produce profitable increases in crop yields from the application of potash. When potash is applied to a soil, the chemical reactions which take place therein depend upon -the equilibrium status of the several forms of potash in that soil. According to Wood and DeTurk (io) the following equilibrium represents the potash situation in any given soil: Primary mineral K -» fixed K (acid insoluble ?=* acid-soluble) ̂ replaceable K ̂ =* water-soluble K. It can be seen that a removal of K from either one of the last three forms of K would cause displacement of the equilibrium to the right with little change in the amount of primary mineral K, except over geologic time. Water-soluble and replaceable K have been considered as synonymous with plant-available forms of K for a number of years. However, according to the equilibrium concept given above, the quantity of fixed K may be as important a factor as the amounts of water-soluble and replaceable K which are present in a given soil at any one time in the potential ability of a soil to supply K for plant growth. It has been established by a number of workers that under most conditions a significant amount of the potash applied to a soil 'enters into a form which is neither water-soluble nor replaceable. This form of potash has been termed fixed K. While adequate proof of the existence of the phe-nomenon of potash fixation has already been furnished by a number of workers, among whom are Wood and DeTurk (io), Bray and DeTurk (i), Hoagland and Martin (4), Volk (9), Page and Baver (5), and Truog and Jones (7), quantitative data on potash fixation by southern soils of known clay mineral type are lacking. It is the object of this paper to obtain some quantitative data on. the fixation of K from KC1 and KoHPOi in two soils whose fine clay mineral fractions were known to be predominantly montmorillonite and kaolinite, respectively.