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Modeling trace gas emissions from agricultural ecosystems

Li, C.S.
Nutrient cycling in agroecosystems 2000 v.58 no.1/3 pp. 259-276
agricultural land, gases, ecosystems, simulation models, prediction, degradation, soil temperature, soil, soil water content, soil pH, vegetation, fermentation, ammonia, nitrous oxide, mathematical models, validity, soil microorganisms, biological activity in soil, soil bacteria, emissions, methane, methane production
A computer simulation model was developed for predicting trace gas emissions from agricultural ecosystems. The denitrification-decomposition (DNDC) model consists of two components. The first component, consisting of the soil climate, crop growth, and decomposition submodels, predicts soil temperature, moisture, pH, Eh, and substrate concentration profiles based on ecological drivers (e.g., climate, soil, vegetation, and anthropogenic activity). The second component, consisting of the nitrification, denitrification, and fermentation submodels, predicts NH3, NO, N2O, and CH4 fluxes based on the soil environmental variables. Classical laws of physics, chemistry, or biology or empirical equations generated from laboratory observations were used in the model to parameterize each specific reaction. The entire model links trace gas emissions to basic ecological drivers. Through validation against data sets of NO, N2O, CH4, and NH3 emissions measured at four agricultural sites, the model showed its ability to capture patterns and magnitudes of trace gas emissions.