黄土丘陵区不同土地利用方式下土壤水分入渗的对比试验

 为更好地掌握黄土丘陵区不同土地利用方式下的土壤水分入渗性能,采用双环法和人工降雨法,分别对陕西省延安市燕沟流域林地、草地、农地3种土地利用方式的土壤水分入渗过程进行了对比试验。结果表明:双环法能较好的反映水向土中的入渗过程;而人工降雨法可以较为真实地反映天然降雨过程中雨水向土中的入渗过程,两者有很大的不同,主要表现在土壤水分的入渗速率变化过程方面。前者测定的土壤水分入渗速率主要受制于土壤的物理性状,而后者:不但与土壤物理性状有关,还与降雨强度有较密切的关系。在人工模拟短历时暴雨条件下, 对于林地和荒坡草地,土壤水分入渗速率有随雨强增大而增大的趋势,而对于裸耕农地,随着雨强的增大,土壤水分入渗速率有降低的趋势。

Comparative experiment of soil infiltration of different land use patterns in loess hilly region

The soil moisture infiltration process of forest, grassland and farmland in Yan' er-Gou basin has been compared by means of the double-rings method and the rainfall-simulator method respectively. The results show that double-rings method can reflect infiltration process of water to soil, but the rainfall-simulator method can reflect infiltration of rainwater to soil in natural rainfall. The two methods have obvious differences mainly about the variation course of soil moisture infiltration rate. Adopting double-rings method, the soil moisture infiltration rate mainly depends on the physical properties of the soil, while using the rainfall-simulator method, it depends on not only physical properties of the soil but also the rainfall intensity. Under short-time storm simulated , infiltration rates of forest and barren slope grassland have the same tendency that it is more and more higher with the increase of rainfall intensity. Infiltration rate of farmland, however, has the opposite tendency.