Modelling nitrous oxide emissions: comparing algorithms in six widely used agro-ecological models

Agricultural soils are the most important anthropogenic source of nitrous oxide (N2O) emissions. This occurs via two main pathways: (1) from microbial-mediated oxidation ammonium to nitrite and nitrate; (2) denitrification. Most agro-ecological models explicitly deal with these pathways albeit different degrees process understanding empiricism. Models that integrate impact multiple environmental factors on N2O emissions can provide estimates fluxes complex agricultural systems. However, uncertainties in model predictions arise differences algorithms, imperfect quantification nitrification denitrification response edaphic conditions, spatial temporal variability resulting variable soil conditions. study compared responses six models. The comparisons showed differently each model. Reasons include inability apportion total flux specific N transformation rates used validate calibrate simplifications represented incomplete interactions between processes modifying as generally not quantified field experiments. Rather, data is reported or net without attributing gross and/or for processes, considering changes occur production Additional measurements quantify all understand affect needed improve algorithms reduce error associated predicted