Chemical Differentiation of Selected Wisconsin Histosols
1970
Isirimah, N. O. | Keeney, D. R. | Lee, G. B.
Samples of 16 Wisconsin Histosols representing a wide range in botanical composition and in various stages of decomposition were used to evaluate selected chemical criteria which may be useful in classification of histic materials. Chemical parameters which related closely with the relative degree of humification were the organic matter cation exchange capacity, total N content of the organic matter, and C/N ratio. The forms of N soluble in 6N HCl varied widely, and no marked trends existed in the N distribution data with respect to the degree of decomposition of the samples. The amounts of C and N extracted from the samples by NaDowex A-1 chelating resin bore no relationship to their degree of decomposition. Hot water soluble C and N decreased with increasing degree of decomposition. The absorbance of 0.025M Na-pyrophosphate extracts of the soils at 340 or 550 mµ was related highly to the amount of organic C in the extracts. Samples were biologically degraded by incubating them under aerobic or waterlogged conditions for 1 year. On the average, Na-resin and hot water extracted less and Na-pyrophosphate more of the organic C from the incubated than from the original samples. The results of this investigation indicate that Na-pyrophosphate solubility is useful in characterizing histic materials and that this extraction procedure can be adapted readily to routine analysis of samples in the laboratory.
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