Numerical analysis of the source-sink alternation of composite global warming potential of the paddy ecosystem in the Yangtze Delta

By coupling the biogeochemical model with plant ecological model, a model was established to reveal the principle of the composite global warming potential transformation in the paddy ecosystem. Validation of the model with the observed data indicated that the model can simulate both the crop growth processes and emissions of CH4 and N2O accurately. Some nu-merical analyses were made to identify the impacts of different fertilizer application on assimilation of CO2 and emissions of CH4 and N2O, and the transformation principle of the composite global warming potential. Based on the results of the numerical analysis, the source-sink alternation of composite global warming potential in the paddy ecosystem was discovered, and some new con-ceptions of fertilizer index such as maximum-sink fertilizer, zero-emission fertilizer are put forward in this paper. The fertilizer scheme for Yangtze Delta was proposed to provide the important scien-tific basis for a sustainable agriculture in this region.