Study On Soil Water Potential Productivity Of Major Crops In The Dryland Farming Areas Of North China

In this paper the dryland farming areas of North China is selected as the study areas. The CERES-Wheat crop model and CERES-Maize crop model were used to simulate soil water potential productivity of wheat and maize in the dryland farming areas of North China. Then we got the potential value of wheat and maize based on the field level and region level. On the basis of the results of the crop model simulation, the crop potential productivity of the dryland farming areas of North China were showed on map and its space distribution characteristic were analyzed and valuated with Geographic information System (GIS) technology method. The conclusions were that as a whole the crop potential productivity in dryland farming areas of North China was tremendous, but the distribution of the potential productivity was unbalanced. The potential value of crop became bigger and bigger from the north to south, as well as from west to east in the research areas. The value of maize potential productivity on average was 4799~12772kg/hm2 and the value of wheat potential productivity was 2827~7025kg/hm2 on field level. The value of the same crop was distinctly difference in different climatic zones. Total tendency was that the zone where the wetness degree was bigger where the value of the crop water potential productivity was bigger. The basal compositor of the value of water potential productivity of the same crop on different climatic zone level was sub humid area >dry sub humid area >semiarid area >dry semiarid area>arid area. The basal compositor of different crops in the same zone was spring maize>summer maize >winter wheat>spring wheat. The simulated result of maize potential productivity were checked against the yields from field trials in Shouyang County,Shanxi Province. The research results show that the yields from the field trials were lower than those predicted by the model. But the coefficients of variation of yields from the model were similar to the coefficient of variation calculated from the yields obtained in the field trials. By comparing the maize yields predicted by the model under different soil profile conditions, the result indicated that for the most years, the water limited yields predicted by the model were almost equal during these years the amount and distribution of rainfall were adequate for the requirements of the crop and differences in the physical properties of the soil were less important. When conditions of water supply were marginal, the value of the maize water potential productivity was conspicuously different. Differences in physical properties of the soil become very important.