间隔覆盖法对塿土坡面土壤水分调控效果

利用室内人工模拟降雨试验，分析研究间隔覆盖条件下坡面土壤水分空间分布及蓄存与利用情况。结果表明：各面积比处理的湿润锋分布形状基本相同，但其深度差别较大，湿润锋在入渗区上部的分布形状体现了间隔覆盖法的特色；各处理入渗区表层土壤含水率沿坡不同位置点略有差异，坡面含水率分布的差异程度有随着覆盖区面积的增大而降低的趋势。各处理剖面含水率分布则符合一般规律，即由表层向深层逐层减少；覆盖面积比及降雨强度是影响入渗区雨水可利用率的重要因素。入渗区的雨水可利用率随面积比增大呈降低趋势，但其入渗量、单位面积承接及蓄存水量均呈增加趋势，这对入渗区植物生长发育及抵抗干旱是有利的。而这些指标随降雨强度增大，则表现出相反的趋势，间隔覆盖法在小雨强下的实施效果较好。对于在不同试验条件下，如何确定适宜面积比进而提高雨水可利用率，以及该方法在不同土壤及降雨条件下的实施效果仍是需要进一步研究的问题。

Soil water regulation effect of interval coverage on Lou soil slope

Using indoor artificial rainfall simulation, spatial soil water distribution, storage and rain water use efficiency were investigated under alternative coverage on Lou soil slope. The results showed that there was no significant difference in wetting front shape of different treatments with different area ratios, but there were big differences in wetting front depths. The shape of wetting front in the upper part of infiltration area embodied characteristics of alternative coverage. The soil water content in surface layer had little difference at different locations along the slope, and soil water content difference decreased as catching area increased. The soil profile water distribution of each treatment decreased gradually from soil surface to deeper layers. Area ratio and rainfall intensity were important factors to influence available rainwater use efficiency. Although available rainwater use efficiency decreased with catching area increasing, its infiltration, acceptable rainfall, storage volume per area increased, which is effective for vegetation growth on infiltration area and resisting drought. But these indices decreased with rainfall intensity. Alternative coverage method showed better effect under lower rainfall intensity. Then, how to determine the appropriate catching area ratio to improve available rainwater use efficiency under different conditions and its effects for different soil slope and rainfall conditions still need further investigation.