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| Characteristics of Soil Infiltration in Watersheds in Loess Hilly Region |
| Wu Qinxiao,Han Bing,Li Yangyang |
| Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, 712100, Yangling, Shaanxi, China |
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Abstract Using the method of core sampler and taking the suit place on up slope, middle slope and down slope of different slope exposures in perpendicular profile to watershed, the characteristics of soil infiltration in forested watershed and rangeland watershed of loess hilly region are studied. The results indicated that the soil infiltration rate in forest watershed is obviously higher than that in rangeland watershed. In the matter of slope exposure, the soil infiltration rate on the ubac usually is higher than that on adret in both watersheds, in which the difference of the two is small in forest watershed, only to take on obviously in the up slope and final infiltration rates are 7.8mm/min and 7.0mm/min. That the soil infiltration rate on the ubac is higher than that on the adret in the rangeland watershed is related to fairly good vegetation growth on the former. In the matter of slope position, it exhibited a tendency of lowering in soil infiltration rate with the drop of position. In other words, the spatial characteristics of soil infiltration rate along the slope is up slope>middle slope>down slope. It is analyzed that the reason may be related with the sediment deposited from the up slope on the down slope, resulting in forming a layer with low infiltration rate on the down slope. For the loess hilly region the process of soil infiltration could be well described by Fang Zhengshan Equation and the mixed use of Fang zhengshan Equation with A. Kostiakov equation, may fully describe the initial and final infiltration rate.
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Received: 13 January 2004
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