新修坡改梯对土壤水库库容的影响

Influence of Newly Built Terraces on Soil Reservoir Storage Capacity

以重庆缙云山山地黄壤为研究对象,在山地同侧但不同高程的地带,分别选取撂荒地和坡耕地2种土地利用类型地块共6块,对比分析其坡改梯工程前后土壤水库库容变化以及坡改梯区域土壤水库对削洪减灾的作用,并对小流域治理惯用的坡改梯工程的理水功能进行评价。结果表明:(1)坡改梯前后,梯地内土壤水库各项库容变化主要受土层厚度变化影响,但在绝对土层不变的情况下,库容大小在一定程度上受到坡改梯前的土地利用方式影响;(2)土壤水库特性与坡改梯引起的土壤性质变化有关,特别是与土壤孔隙、质地相关指标有关;(3)在百年一遇的设计暴雨条件下,用简化的概念型产流模型进行模拟,发现坡改梯能在理论上削减30%以上的径流,对农业区域旱涝灾害防治有重要作用。

In this study, our goal was to estimate the water regulating ability of terraces, which was one of the most important soil and water conservation measures in the Three-Gorge Reservoir Region, as well as in south China. Six testing fields at the different height were selected, which with two kinds of land use types including abandoned land and slope farmland, and then we analyzed the storage capacity of yellow soil and the impact factors of soil reservoir after terracing in Jinyun Mountain, Chongqing. The results showed as follows： （1）In the test area, soil reservoir storage was mainly affected by the thickness of the soil layer, and land use types before terracing were also related. （2）Soil property changes, especially soil porosity and soil texture changes caused by terracing, also had an important impact on soil reservoir characteristics. （3）Under the designed once-in-a-century rainstorm in this area, terraces could reduce more than 30% of the storm run- off theoretically simulated by simplified runoff formation model, so terraces would play an important role in drought or waterlog prevention.