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Nitrogen Effects on Conservation of Carbon during Corn Residue Decomposition in Soil
Author(s) -
Green C. J.,
Blackmer A. M.,
Horton R.
Publication year - 1995
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/sssaj1995.03615995005900020026x
Subject(s) - stover , loam , mineralization (soil science) , corn stover , agronomy , human fertilization , soil water , nitrogen , nitrogen cycle , soil organic matter , chemistry , decomposition , environmental science , soil carbon , crop residue , organic matter , environmental chemistry , field experiment , soil science , ecology , biology , biochemistry , organic chemistry , hydrolysis , agriculture
Nitrogen fertilization is widely recognized for its potential to help maintain soil organic matter (SOM) concentrations by increasing plant growth and amounts of plant material decomposed in soils. We studied possible mechanisms by which annual additions of more N than needed to maximize yields of corn ( Zea mays L.) could cause losses of SOM. Various amounts of stover and NO − 3 were added to a Galva silty clay loam (fine‐silty, mixed, mesic Typic Hapludoll), and NO − 3 concentrations and CO 2 evolution were monitored for periods up to 90 d at 24°C in the laboratory. The added NO − 3 suppressed mineralization of C from SOM and stimulated mineralization of C from stover. Adjustment of rates of stover decomposition to temperature regimes normally encountered in Iowa fields after harvest showed that stover decomposition would not be complete within 1 yr and that increases in NO − 3 availability decreased the amount of stover C remaining in the soil. This effect of NO − 3 could explain how additions of unneeded N could decrease concentrations of SOM in long‐term studies in which residues and NO − 3 are added in annual cycles. These observations suggest that practices that reduce unnecessary fertilization could help conserve SOM and reduce net amounts of CO 2 released to the atmosphere.