• 研究论文 •

### 不同降雨条件下坡长对喀斯特坡面土壤侵蚀的影响

1. 1贵州师范大学喀斯特研究院, 贵阳 550001;
2国家喀斯特石漠化防治工程技术研究中心, 贵阳 550001;
3贵州省水土保持监测站, 贵阳 550002
• 收稿日期:2020-07-23 接受日期:2020-10-31 出版日期:2021-01-15 发布日期:2021-07-15
• 通讯作者: * E-mail: rlfer@126.com
• 作者简介:黄 凯, 男, 1995年生, 硕士研究生。主要从事土壤侵蚀与水土保持研究。E-mail: 1050568166@qq.com
• 基金资助:
贵州省科技支撑计划项目([2019] 2847)和国家自然科学基金项目(31760243)

### Effects of slope length on soil erosion of Karst slope under different rainfall conditions

HUANG Kai1,2, LIU Rui-lu3, QIN Li3, SONG Tao3, LIU Zhong-xian3, LI Rui1,2*

1. 1School of Karst Science, Guizhou Normal University, Guiyang 550001, China;
2State Engineering Technology Institute for Karst Desertification Control, Guiyang 550001, China;
3Guizhou Provincial Monitoring Station of Soil and Water Conservation, Guiyang 550002, China
• Received:2020-07-23 Accepted:2020-10-31 Online:2021-01-15 Published:2021-07-15
• Contact: * E-mail: rlfer@126.com
• Supported by:
Guizhou Province Science and Technology Support Plan Project ([2019] 2847) and the National Natural Science Foundation of China (31760243).

Abstract: Based on the runoff and sediment yield data from 59 erosive rainfall plots with different slope lengths (5, 10, 15, 20, 25 m) in Shiqiao small watershed of Guizhou Province from 2012 to 2014, we analyzed the relationship between runoff and sediment yield and slope length under diffe-rent rainfall conditions. The results showed that, with the increases of slope length, the runoff yield of slope showed a ‘V-shape’ pattern, the sediment yield of slope increased first and then decreased. According to rainfall amount, rainfall duration, and average rainfall intensity, the 59 erosive rainfall in the study area could be divided into three types, including type A with short duration, heavy rain intensity and small rainfall, type B with medium duration, light rain intensity and medium rainfall, and type C with long duration, medium rain intensity and large rainfall. The relationships between runoff and sediment yield and slope length were different under different rainfall patterns. There was about 20 m critical slope length of sediment yield under type A and B. The sediment yield gradually increased with the increases of slope length under type C. There was a good cubic function relationship between slope length and runoff and sediment yield under different rainfall patterns. The variable amplitude of runoff and sediment yield was different among different slope lengths. Except the slope length of 15-20 m, the variable amplitude of runoff and sediment yield under type C was relatively large. The variation amplitude of sediment yield was significantly higher than that under other rainfall patterns. The total runoff yield under different rainfall patterns was type A>B>C. The sediment yield under type B was the smallest, that of type A at the slope length of 20 m was the largest and that of type C at other slope lengths was the largest. The correlation between compound rainfall factors and runoff and sediment yield was better than that of single rainfall factor under type A (common rainfall type in the study area). Rainfall amount (P), the pro-duct of rainfall duration and maximum 30 min rainfall intensity (TI30), product of rainfall duration and average rainfall intensity (TI), product of rainfall amount and rainfall duration (PT) were significantly correlated with the runoff and sediment yield. Among those factors, P and TI had the strongest correlation with runoff. Further, the relationship between them and runoff under different slope lengths could be expressed by linear equation and S-curve. There was a good cubic function relationship between the sediment yield and its corresponding rainfall factors under different slope lengths.