Aluminum in Soils: VII. Interrelationships of Organic Matter, Liming, and Extractable Aluminum with “Permanent Charge” (KCl) and pH-Dependent Cation-Exchange Capacity of Surface Soils
1965
McLean, E. O. | Reicosky, D. C. | Lakṣmaṇan̲, Ci.
Seven Ohio surface soils which had been incubated with little or no lime and with sufficient quantities to nearly neutralize them were analyzed for “permanent charge” or KCl- and pH-dependent cation-exchange capacity (CEC). The low- and high-lime soils were also analyzed for both of these components of CEC after organic matter was destroyed with hydrogen peroxide. CEC was also determined by extraction with 1n NH₄OAc-pH 7. Changes in both the KCl-CEC and pH-dependent CEC caused by liming and by destruction of organic matter appeared to be the result of activation or inactivation of exchange sites of the organic matter initially occupied by Al. Only in the case of one soil (Venango, A2 horizon) did hydroxy-Al appear to be equal to organic matter in effect on pH-dependent CEC.
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