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Nitrification and Denitrification during Miscible Displacement in Unsaturated Soil
Author(s) -
Kirda C.,
Starr J. L.,
Misra C.,
Biggar J. W.,
Nielsen D. R.
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/sssaj1974.03615995003800050024x
Subject(s) - tracer , nitrification , chemistry , leaching (pedology) , effluent , soil science , soil water , nitrogen , environmental engineering , geology , environmental science , physics , organic chemistry , nuclear physics
Nitrification and denitrification during the leaching of a pulse of NH 4 NO 3 applied to the surface of soil columns are analyzed experimentally and theoretically. Experimentally, unsaturated soil columns of two lengths were leached steadily with a tracee solution containing NH 4 NO 3 while the air‐filled portions of the columns were being flushed simultaneously with air. During these steady state conditions, a pulse of tracer solution containing either 15 NH 4 + or 15 NO 3 ‐ was leached through the columns. The words tracee and tracer signify that both solutions were chemically identical with the latter containing a greater proportion of 15 N. Steady‐state tracee concentration distributions within the columns as well as the transient tracer concentration distributions in the effluent were analyzed assuming first‐order kinetics. Values of both the rate coefficients and the concentration distributions stemming from the tracee and tracer measurements were in general agreement. The agreement between the measured and theoretical results are discussed in terms of soil water properties and the kinetics of microbial populations.