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A Steady‐State Model of Isotopic Fractionation Accompanying Nitrogen Transformations in Soil
Author(s) -
Shearer G.,
Duffy J.,
Kohl D. H.,
Commoner B.
Publication year - 1974
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/sssaj1974.03615995003800020030x
Subject(s) - nitrification , nitrate , nitrogen , soil water , fractionation , chemistry , ammonium , environmental chemistry , nitrogen cycle , steady state (chemistry) , incubation , ammonium nitrate , soil science , environmental science , chromatography , biochemistry , organic chemistry
A steady‐state mathematical model of isotopic fractionation accompanying certain nitrogen transformations in soils is developed. The model takes into account ammonification, nitrification, and immobilization; and predicts that the 15 N/ 14 N ratios of nitrate and ammonium ion depend in part upon the ratio of the rates of immobilization and ammonification. The ratio of the rates of immobilization to nitrification under field conditions is unlikely to be the same as under the conditions of laboratory incubation experiments. Therefore, this prediction provides a possible explanation for differences observed between the 15 N/ 14 N ratio of nitrate extracted from soil cores and that of nitrate released during laboratory incubation of the same soils. The model described is ammenable to experimental test. If verified, an expanded version of the model may be a useful aid in the study of nitrogen transformations in the field.