A calculation method of soil water resources based on SCS-CN model

Soil water resources are the most important water resources for agricultural production and ecological environment. However, currently, there has been yet no consensus on the concept and calculation method of soil water resources. According to water balance theory and recharge of soil water resources, this paper firstly defined soil water resources in terms of agriculture and then proposed a calculation method of soil water resources based on soil conservation service curve number model (SCS-CN model). Besides, the annual dynamic variation of soil water resources in hydrological years with different frequency and the soil water resources of main crops in their growth periods were calculated by taking the example of Baoding Plain, Hebei, China. Studying the variation of soil water storage in years with different frequency is of vital significance for addressing annual regulation of soil water. Additionally, defining soil water resources of crop in growth period can effectively guide irrigation, save irrigation water, and scientifically, rationally balance water demand and supply of crop in growth period. Confronting the increasing shortage of water resources, scientifically, reasonably evaluating soil water resources in a region and efficiently utilizing these resources can effectively reduce irrigation resources from surface water and groundwater and make full use of soil water resources for agricultural production. This research is of vital significance for promoting the sustainable development of water-saving agriculture, effectively mitigating the crisis of water resources and improving ecological environment.