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Studies on Some Factors Affecting the Quantitative Estimation of the Exchange Capacity of Organic Matter
Author(s) -
Broadfoot Walter M.,
Tyner Edward H.
Publication year - 1940
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/sssaj1940.036159950004000c0029x
Subject(s) - citation , library science , context (archaeology) , computer science , sociology , history , archaeology
WALTER M. BROADFOOT AND EDWARD H. TVNER2 METHODS which are satisfactory for detennining the base-exchange capacity of mineral soils can not be applied indiscriminately for determining the exchange capacity of fresh or decomposed plant residues. Preliminary investigations on undecomposed tree leaves, peat moss, and forest humus layers indicate that: I. The exchange capacity of organic residues varies with the cation used for saturation of the exchange complex, e.g., the exchange capacity in M.E. per 100 grams for sumac leaves saturated with various cations was as follows: NH4 = 16.9; Mg = 67.6; Ba = 76.3; and Ca =101.2. The differences in M.E. of Mg, Ba, and Ca absorbed by the other plant tissues included in these studies were not so striking as for sumac. The absorptive capacity, however, of organic residues for ammonium was found in all cases to be considerably less than that for the divalent cations. The differences noted in the absorptivt capacity of organic matter, particularly fresh tissue, is probably due to the multiplicity of compounds active in the absorption and to differences in the solubility of the various absorp-