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pH‐Dependent Bonding of Potassium by a Spodosol
Author(s) -
Bartlett R. J.,
McIntosh J. L.
Publication year - 1969
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/sssaj1969.03615995003300040016x
Subject(s) - chemistry , cation exchange capacity , potassium , podzol , saturation (graph theory) , phosphate , ion exchange , soil ph , fluoride , inorganic chemistry , soil water , ion , environmental chemistry , soil science , biochemistry , geology , organic chemistry , combinatorics , mathematics
A Spodosol Ap high in extractable Al and pH‐dependent CEC was limed to pH 6.3, producing deficiency of K in tomato seedlings. This was evidenced by lowered plant yields and concentrations of K in the tissue, compared with plants grown in acid samples of the soil. Soil chemical studies were undertaken to further examine the magnitude and mechanism of this phenomenon. Treatment of acid soil samples with increasing levels of CaCO 3 , CaSiO 3 , CaHPO 4 , or CaF 2 markedly raised CEC along with pH and lowered activity of K and extractable Al. It was hypothesized that hydroxyl, phosphate, or fluoride ions neutralized positive charges on Al. This freed negatively charged exchange sites, and thereby raised CEC. With increased CEC, the percentage saturation of the exchange complex with K (and, therefore, availability of K) was decreased, compared with the untreated soil.