中文摘要：

模型为一维模型，其主要框架由土壤水分运动、N素迁移转化以及水稻生长3个模块组成。在土壤水分运动模拟中，考虑了可能存在的饱和流和非饱和流：在N素运移中将土壤中的NH4^＋、NO3^＋和尿素视为土壤溶质，用对流弥散方程模拟其在垂直方向上的运移；在N素转化过程中考虑了尿素水解、有机N矿化、氨挥发、硝化、反硝化以及NH4^＋的吸附这6个过程：对于作物生长的模拟，选用了ORYZA水稻生长模型，并结合田间实验修改了其中一些参数。使用该模型对3年的田间试验进行了模拟验证，对于土壤中矿质态N素以及水稻生长的模拟，都得到了较好的模拟结果，通过与实测值的分析比较，耕作层的NH4^＋-N浓度，水稻各部分的生物量模拟值与实测值的吻合都达到了显著水平。

英文摘要：

A one-dimension model of nitrogen cycling was described in this paper. The model constituted of three modules： soil-water-movement module, nitrogen-transport module and rice-growth module. In simulating soil water movement, potential saturated and unsaturated flow in soil were considered; In simulating nitrogen transport, NO3^＋, NH4^＋, and urea were taken as soil solutes and their vertical movement were simulated by convection-dispersion equation; In simulating nitrogen transformation, urea hydrolysis, mineralization, ammonia volatilization, nitrification, denitrification and ammonium adsorption-desorption were considered together; In simulating crop growth, ORYZA rice-growth model was selected and some parameters were modified by field experiment. The model was validated by a 3-year field experiment, and simulated results of mineral nitrogen in soil and rice-growth were proved well. Comparison analysis showed there were significant correlation between simulated and measured ammonium nitrogen concentrations, as well as dry biomass of rice different organs.