Modeling of Soil Water Drainage and Nitrate N Leaching in Arable Soils

The vertical transport of soil water and nitrate N in main soil groups (yellow fluvo-aquic soils and Aeolian sandy soil) in Huang-Huai-Hai Plain was simulated by HYDRUS-1D model. Sensitivity analysis of model parameters showed: Saturated hydraulic conductivity is the most sensitive factor for two soil groups, and saturated water content takes second place. Numerical simulation indicated: under conventional management of water and nitrogen, soil water deep drainage and nitrate N leaching are very serious. The water leakage amount of Aeolian sandy soil is more than that of yellow fluvo-aquic soils, reaching 34.3 cm and 22.7 cm, respectively, about 42.1% and 74.6% of total water irrigated. The nitrate N leaching amount of Aeolian sandy soil is more than that of yellow fluvo-aquic soils, reaching 108.0 kg/hm和76.6 kg/hm, respectively, about 25.3% and 14.3% of total N applied.