[Simulating net primary production of rice and wheat crops: model establishment]

On the basis of the principles of plant physiology, agro-meteorology and soil environment, net primary production of rice and wheat crops was modeled. The model includes two main functional modules: photosynthesis and respiration, and nitrogen transport within soil-plant system. The processes of photosynthesis and respiration are driven by environmental variables and plant nitrogen content. The transportation of nitrogen within soil-plant system is determined by simulating the processes of crop nitrogen uptake, soil nitrogen mineralization and synthetic nitrogen release.