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Simulation of Nitrogen‐15 Immobilization by the Model NCSOIL
Author(s) -
Hadas Aviva,
Molina J. A. E.,
Feigenbaum Sala,
Clapp C. E.
Publication year - 1987
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/sssaj1987.03615995005100010022x
Subject(s) - mineralization (soil science) , decomposition , chemistry , nitrogen , environmental chemistry , biomass (ecology) , nitrogen cycle , kinetics , soil water , organic matter , soil science , environmental science , agronomy , organic chemistry , biology , physics , quantum mechanics
The computer model NCSOIL computes the dynamics of C and N transformations in soil. In its original version, the microbial biomass assimilated organic N from the decay of organic pools, and inorganic N was immobilized only when decomposed organics were deficient in N with respect to biomass needs for growth (NCSOIL—direct version). A new version was presented in which it was assumed that microbial biomass immobilized N only from the inorganic pool, while the decay of organic N always resulted in N mineralization (NCSOIL‐MIT version). NCSOIL‐MIT was calibrated and tested for the incorporation of inorganic 15 N in the organic soil N against experimental data and compared with the direct version. Net N mineralization was highly sensitive to the microbial efficiency of soil decomposable organic C incorporation. An efficiency of 0.2 gave a good account of net N mineralization for soils unamended with organic substances. NCSOIL‐MIT simulated the incorporation of 15 N, added as NH 4 , into the organic soil pools. The kinetics of 15 N immobilization was sensitive to microbial efficiency as well as to other parameters that control soil N turnover. NCSOIL—direct version required the decomposition of polysaccharide‐like material in order to obtain 15 N incorporation in the soil organic pools, and the kinetics of 15 N immobilization depended on the rate of polysaccharide decomposition.