黄土丘陵沟壑区不同水保措施条件下土壤水分状况

    Soil water condition under different measures of soil and water conservation in loess hilly and gully region

    • 摘要: 黄土高原土壤水资源对植物的生长发育意义重大。水土保持措施会影响土壤水分的静态分布和动态过程。该文通过定位监测并引入土壤水分亏缺补偿度指标,旨在明确黄土丘陵沟壑区不同水土保持措施下土壤水分动态特征和雨季前后土壤水分的亏缺与补偿情况。结果表明:不同水土保持措施雨季前后土壤储水均处于亏缺状态,7月份土壤储水亏缺得到缓解;8月份表层土壤储水亏缺加剧;雨季后的10月份土壤储水均得到恢复。降雨对退耕坡地和梯田土壤水分均有正补偿作用。水平阶90 cm处和160 cm以下出现负补偿现象。鱼鳞坑在30 cm处出现负补偿。在0~200 cm土壤剖面上,土壤储水亏缺补偿度依次为退耕坡地>梯田>鱼鳞坑>水平阶。由此可见,不同水土保持措施对土壤水分季节变化和垂直变化,以及降雨对土壤水分的补偿作用均产生不同影响。

       

      Abstract: Soil water resource is very important to the growth and development of plants on the Loess Plateau. Soil and water conservation measures have impacted on the static distribution and dynamic process of the soil water resource. Based on data collected by random survey of soil moisture and compensation degree of soil water storage deficit, the soil moisture dynamics and the compensation characteristics of soil water deficit under different measures of soil and water conservation in the loess hilly and gully region were analyzed. The results show that, no matter before or after rainy season, soil water storage under different measures of soil and water conservation was deficient and then increased in July. In August, soil water storage deficit in surface layer increased. After rainy season, soil water storage deficit was restored by precipitation in October. The compensation effect of precipitation on soil water storage of crop land and terraced land was positive. But this effect was negative at the depth of 90 cm and below 160 cm on the narrow level-belt land, and the depth of 30 cm on the fish-scale-pit land. In the 0~200 cm soil profile, land types were in the descending order of crop land, terraced land, fish-scale-pit land, and narrow level-belt land, in terms of compensation degree of soil water storage deficit. To sum up, soil and water conservation measures can influence the seasonal and vertical variations of soil water storage and the compensation impact of precipitation on soil water.

       

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