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Chemical Distribution of Added Nitrogen in Soils
Author(s) -
Cheng H. H.,
Kurtz L. T.
Publication year - 1963
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/sssaj1963.03615995002700030029x
Subject(s) - chemistry , humin , alkali metal , soil water , hydrolysis , amino sugar , nitrogen , alkali soil , organic matter , sugar , organic chemistry , humic acid , soil science , fertilizer , environmental science
The distribution of added nitrogen (N) among the various components of soil N was determined, using isotopic tracing techniques. Three lysimeter soils, previously fertilized with N 15 ‐enriched N, were studied. Methods of fractionating soil N were modified to permit estimation of the isotopic ratio as well as the N content of the different fractions. Soil N was fractionated into: exchangeable NH 4 + plus NO 3 ‐ , fixed NH 4 + , N in acid hydrolyzate, and acid‐insoluble humin N. The N in acid hydrolyzate was further separated into the alkali‐labile N and the alkali‐stable N. The alkali‐labile N consisted of hydrolyzed NH 4 + and amino sugar N. The alkali‐stable N was divided into soluble N, which included the amino acid N, and acid‐soluble but alkali‐insoluble humin N. Validity of the classification was discussed. Usefulness of N 15 data was also evaluated. Estimation of the distribution of added N showed that over 90% of added N in soils was found in the hydrolytic products of soil organic matter, mainly as amino acid N, amino sugar N, and other soluble N.