干旱区生态环境知识资源中心

The rainfall is the main soil water supply to the soil of desert-steppe. It divides into three parts, evaporation, infiltration and runoff, after falling on to the surface. Those three parts are affected by many factors. Studies of rainfall division in desert-steppe were rare, the proportions of evaporation, infiltration and runoff are uncertain. So Under the condition of different vegetation, we conduct six times rainfall simulation experiment under different rainfall intensity. Simulation shows that rainfall process, the surface coverage and soil condition affect division. The evaporation section of rainfall accounted for 1/2 similar to 2/3. Infiltration section accounted for 30% similar to 50%. Runoff is the smallest. The rainfall intensity plays a decisive role on the runoff. Different vegetation coverage, division proportion is different. The interception and delay function of vegetation main effect evaporation and runoff, it can make the evaporation increased to more than 70%, reduce runoff to a third. Water content of soil profile before rainfall is the main factors affecting infiltration volume. The soil moisture before rain affects the infiltration rate at the beginning of rainfall. If rainfall duration is long enough, infiltration capacity is almost a constant.