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Rate of Nitrogen Mineralized from Incorporated Crop Residues as Influenced by Temperature
Author(s) -
Vigil M. F.,
Kissel D. E.
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/sssaj1995.03615995005900060019x
Subject(s) - soil water , mineralization (soil science) , crop residue , residue (chemistry) , chemistry , nitrogen , crop , soil science , agronomy , mathematics , environmental science , agriculture , biology , ecology , biochemistry , organic chemistry
Methods are needed to predict seasonal mineralization of N when crop residues are added to soils in order to assess N availability to crops. The objective of this investigation was to evaluate and develop methods for predicting the effect of temperature on the rate of N mineralization (N min ) from crop‐residue‐amended soils maintained at near‐optimum soil water content. Unamended and crop‐residueamended soils were incubated at temperatures between 5 and 35°C to obtain N min rates for calculation of Q 10 values, defined as the ratio of reaction rates at a temperature interval of 10°C. Measured Q 10 depended on the C/N ratio of the residue and incubation time, indicating that for predictive purposes a single Q 10 value is inadequate for describing the effect of temperature on crop‐residue N min . Temperature functions were developed from N min data collected from unamended soils incubated at four temperatures under laboratory conditions. These functions were then tested in the MINIMO model (a subroutine of CERES‐MAIZE) for residue‐amended soils at four temperatures for up to 160 d. Model‐predicted mineralizations was close to measured N min for most crop‐residue‐soil mixtures tested. The use of the new temperature equations improved the precision of the model, reducing the residual sum of squares (RSS) from 9797 to 5286. However, the modified model was not able to accurately predict N min for crop residues with a C/N ratio of 10 and 28. Inadequate prediction at these C/N ratios may be related to how the model allocates the pool sizes for soluble and insoluble plant N and the cellulose‐hemicellulose pool size of the crop residues.