一个稻田土壤-作物体系的氮素循环模型

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。

A Nitrogen Cycling Model in Soil-Crop System of Paddy Soil

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.