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POTASSIUM FIXATION IN SOME KENYAN SOILS
Author(s) -
BARBER R. G.
Publication year - 1979
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1979.tb01027.x
Subject(s) - potassium , soil water , chemistry , fixation (population genetics) , kenya , sieve (category theory) , amorphous solid , mineralogy , zoology , geology , soil science , mathematics , crystallography , biochemistry , biology , ecology , organic chemistry , combinatorics , gene
Summary Potassium fixation was measured for 13 Kenyan soils with a range of applied potassium (0 to 1000 mg kg −1 ). The fixed potassium was measured, and hence is defined in this study, by the difference between the amount of applied K and the increase in the extractable K after equilibration, using a single ‘equilibrium’ extraction procedure with 0. 25 M Cad, as the extractant. At application rates of 50 and 1000 mg kg −1 the fixed potassium varied from −52% to 64% and 7% to 39% respectively. A correlation was found between the K fixation and % clay content at the 1000 mg kg 1 application rate. Estimates of the % fixation by the clay fractions gave 53 to 80% for montmorillonites, 48 to 66% for amorphous clays and 19 to 32% for kaolinites. It is suggested that the amorphous clays may fix potassium by a ‘sieve’ mechanism.