Rice Nitrogen Management Using Three Crop Models---a Case Study in Southeast China.

Nitrogen fertilization scenarios were set according to the conventional management. Then three rice growth models (ORYZA2000, RiceGrow, CERES-Rice) were used to simulate rice yield under different nitrogen scenarios. Considering of income and nitrogen fertilizer price and labor cost, we analyzed the impact of nitrogen levels, splits and times on yields and fertilizer-use efficiency. Optimum nitrogen management schemes were proposed, which will improve nitrogen-use efficiency, increase farmers' incomes and reduce the environment pollution. The results showed that the applied amount of nitrogen fertilizer has a great effect on rice yield, the yield increases with the increase of nitrogen application rate but the incomes and nitrogen-use efficiency will reduce. The recommended nitrogen managements were proposed based on yield, incomes, and nitrogen-use efficiency.