Calculating model of soil water resources in plain area

The assessment of soil water resources is important to the reasonable exploitation of water resources and the improvement of agricultural water-saving technique in semiarid area.Based on the small-scale hydrology theory and the effective rainfall,a new soil water resources calculating model was put forward,which calculated the soil water resources by water balance principle.According to the data of Ranzhuang experimental station,Hebei Province,calculation was made of the soil water resources' value of high flow year and low flow year with 642.68 mm and 415.34 mm respectively.The proportion of rainfall in soil water resources was 85% and 76% respectively,while the proportion of condensation water was 15% and 24% respectively.The result accorded with the fact.The proportion of condensation water was large and can not be ignored in calculating the quantity of soil water resources.The results show that the calculating model based on the effective rainfall is another valid method to calculate the quantity of soil water resources for small-scale hydrology and has better applicability.