花岗岩风化土不同土层抗蚀性差异分析

Studies on the Variation of Soil Antierodibility of Collapse Horizons of Weathered Earth in Granite Region

土壤的抗蚀性即土壤抵抗外力对其破坏和搬运的能力,土壤抗蚀性越强,受到的侵蚀破坏就越少。本文通过对通城崩岗区花岗岩发育的淋溶层、淀积层、母质层进行多次人工模拟降雨试验,在一定雨强、坡度的条件下,收集径流、泥沙来研究崩岗区花岗岩发育的不同土层的抗蚀性。结果表明:崩岗区花岗岩发育的淋溶层、淀积层、母质层的抗蚀性有显著差异,各土层的入渗率呈现稳定差异,淀积层的稳定入渗率是淋溶层的1.25倍,母质层的2.27倍;且输沙率差异明显,母质层的平均输沙率是淀积层的1.79倍,淋溶层的3.11倍。结合3层土理化性质和土壤粒径分析可知,母质层的抗蚀性最弱,淀积层次之,淋溶层最强,其中决定3层土抗蚀性大小的主要因素是土层中小颗粒含量和颗粒间的粘结能力。

Soil anti-erodibility is the ability to resist to the damage and removal from external forces, the stronger the anti-erodibility of soil is, the less erosion damages it suffers. This paper aimed to conduct the research on anti-erodibility of different soil layers developed from the granite in collapsed gullies through lots of artificial simulation of rainfall experiments with eluvial horizon, illuvial horizon and parent material horb zon of collapsed gullies granite development in Tongcheng County and collecting runoff and sediment under certain rainfall intensity and slope conditions. The results showed that there was a significant anti-erodihility difference among eluvia｜ horizon, illuvial horizon and parent material horizon of collapsed gullies granite development while the infiltration rate of different soil layers showed the stable difference, the stable infiltra- tion rate of illuvial horizon was 1.25 times greater than the eluvial horizon and 2.27 times greater than the parent material horizon. The transport rates showed a sharp distinction. The average sediment transport rate of parent material horizon was 1.79 times greater than the illuvial horizon, 3.11 times greater than the eluvi- al horizon. Combining with analysis of physical and chemical properties of three layers and particle sizes in the soil profile, soil anti-erodibility of the parent material horizon is the weakest, followed by the illuvial horizon, while eluvial horizon is the strongest. The main factors determining soil anti-erodibility of the three layers are the contents of medium and small particle sizes and bonding capability of particles.