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Exchangeability of Soil Potassium in the Sand, Silt, and Clay Fractions as Influenced by the Nature of the Complementary Exchangeable Cation
Author(s) -
Merwin H. D.,
Peech Michael
Publication year - 1951
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/sssaj1951.036159950015000c0026x
Subject(s) - silt , chemistry , citation , library science , geology , computer science , geomorphology
IN A previous study (2) of the potassium-supplying power of several representative New York soils, the exchangeable potassium content of some soils was found to decrease rapidly upon continuous cropping to the point where the plants showed severe symptoms of potassium deficiency whereas in other soils the amount of exchangeable potassium remained constant at a relatively high level despite the large amounts of potassium removed by six consecutive crops. On this latter group of soils, with a high potassium-supplying power, the plants obviously absorbed large amounts of nonexchangeable potassium either directly or after conversion to the exchangeable form. Preliminary leaching experiments carried out with these soils showed that the exchangeable potassium content of some of these soils could be restored to approximately the original level within an hour after leaching the soils with 0.2N acetic acid or IN calcium acetate solution. On the other hand, the release of nonexchangeable potassium was virtually inhibited even upon prolonged moist storage in the ammonium-saturated soils following the leaching with IN ammonium acetate solution and alcohol. It was apparent that only the ammonium acetate solution could effect a clear-cut separation of the exchangeable potassium. In attempt to develop a rapid laboratory method for evaluating the potassium-supplying power of soils based on measuring the amount of potassium released, by the soil upon successive extraction or leaching with an appropriate extracting solution, acetic acid and several salt solutions of monoand divalent cations were investigated. The contribution of the sand, 'silt, and clay fractions to the total amount of potassium released by these soils in the presence of different complementary exchangeable cations was also determined. This paper presents the results obtained on four soils taken from the same stock samples used by Chandler, et al. (2) in their greenhouse studies on the release of potassium upon continuous cropping with Ladino clover.