Study on WaterSaving Techniques of Agriculture in Semihumid and Liable to Drought Region

Increasing use efficiency of the soil moisture is a key of watersaving agriculture. The adoptable watersaving techniques include mulching, varieties and chemical regulation agents， which not only can reduce evaporation and leakage of soil moisture and increase the water capacity of soil to raise water use efficiency, but also can enhance the effective change of the plants to soil moisture and increase the efficiency of water use by plant. Among them,the water capacity of soil in 1 m depth can increase about 169.5 m^３, the irrigation water can save around 2100　mm/hm²， and the available use efficiency of the soil moisture can raise 26.8 % by straw mulching straw; the water use efficiency of plant can raise from 0.54 kg/mm to 0.56 kg/mm by selecting the resistant varieties; the water percentage of topsoil and leaves increase 4.7 % and 4.9 % respectively by applying the chemical agents upon inhibiting evaporation and conserving soil moisture. The adoption of the savingwater techniques of agriculture which combined the reasonable and effective utilization of limited water resources， with saving water of plant to the almost extent is one of the important ways for the steady and sustainable increasing in production in the semihumid and liable to drought regions in China.