Water and Nitrogen Optimal Management Under Agricultural Field of the North China Plain

The North China Plain was selected as the research region of this paper. Based on data of the Second National General Soil Survey, a simplified distribution map of soil types in the North China Plain was obtained with geographic information system (GIS) method (ARC/INFO). There were 72 soil types with the representative profiles. A multiple goal hybrid programming model was also established in this paper, based on the simulation of regional soil water and nitrogen behaviors under agricultural field. Its programming variables were irrigation and nitrogen application. The programming goals were grain yields, nitrogen leaching at 1 meter depth, water use efficiency (WUE) and nitrogen use efficiency (NUE). A linear weight coefficient selection method was employed to resolve the programming model. Suitable quantities of water and nitrogen of winter wheat-summer maize rotation system were determined for 6 soils with different texture in different hydrologic year types.