不同次降雨条件对黄土区主要地类水沙动态过程的影响及其机理研究

Experimental study on runoff and sediment process in primary-lands in loess hilly regions under different rainfall conditions

通过野外人工模拟降雨试验,对不同次降雨条件下黄土丘陵区主要地类坡面水沙过程进行对比研究,分析降雨因素与产流产沙过程的关系,并对林草植被的水土保持机理做了有益探讨。结果表明,降雨因素是影响径流和产沙的主要动力因素之一,在不同降雨条件下,各地类小区产流产沙过程线均表现出较为强烈的波动趋势,产沙过程较产流过程波动更为剧烈,在植被覆度较低的黄土丘陵区,降雨强度是产流产沙的主控因子。不同地类的产流量和产沙量的变化,随着降雨强度的增强而增加,随着植物被覆度的增加,由于林草植被措施具有蓄水固土作用,减沙效益显著,降雨的影响相对降低。因此将陡坡耕地退耕还林还草是解决水土流失、恢复黄土高原良性生态环境的必由之路。

The process of runoff and sediment yield in primary-lands in the loess hilly region under different vegetation covers and artificial rainfall conditions in the field plot was studied. The effect of rainfall on the process of runoff and sediment yield was analyzed. The results show that the rainfall is one of the most important factors. Under different rainfall conditions, the runoff and sediment yield processes in all types of land showed fluctuated trend and the fluctuation of sediment is stronger than runoff. In the loess hilly region with lower vegetation covering degree,the rainfall intensity is the primary effect factor and the runoff and sediment amounts increase with rainfall intensity. However,due to foresty-vegetation＇ s function of soil and water conservation the effect of rainfall effect is relatively reduced. It＇ s essential matter to change the sloping tillage land to forest and grass land in order to restore better eco-environment in the loess hilly region.