由于缺乏长期定位观测资料,西南喀斯特山区坡地水土流失规律一直不明确,严重影响了该区石漠化综合治理和水土流失防治工作的成效和进程。该文基于13个大型径流小区(宽20m、投影面积〉1000m2)5a(2006-2010年)的定位观测资料,分析了桂西北喀斯特峰丛洼地不同利用方式坡面降雨产流规律和地表侵蚀产沙特征。结果表明:观测期内年降雨量为1300~2000mm,无论平水年还是丰水年,不同利用方式坡面次降雨径流系数〈5%,地表产流很少,降雨几乎全部入渗。不同利用方式地表侵蚀产沙模数虽有较大差异,但土壤侵蚀以微度(〈30t/(km2a))为主,部分甚至只有0~5t/(km2a)。植被类型、土地利用方式对坡面降雨产流的影响较小,但人为干扰会增加地表侵蚀产沙量。该文为喀斯特坡地植被恢复重建和水土流失防治提供参考。
Due to shortage of long-term observation data, law of soil and water loss on hillslope is not clear in karst regions of southwest China, which heavily influences the progress of comprehensive control of rock desertification and soil and water loss. Based on five-year observation data from thirteen big runoff plots with projected area more than 1000 m2 (20 m width), surface runoff and soil erosion on dolomite hillslope with different land uses were investigated from 2006 to 2010 in the karst peak-cluster depression area of northwest Guangxi in China. The results showed that annual rainfall varied from 1300 to 2000 mm during the observation periods, and whether in rainy or normal year, event runoff coefficients were less than 5% on hillslope with different land uses, which indicated that surface runoff was very low and all rainwater almost infiltrated into soils on karst hillslope. Surface soil erosion modulus on hillslope had great differences among different land uses, but soil erosion were mostly weak (〈30 t/km2·a), and even only 0-5 t/km2·a. Vegetation and land-use types had relatively small effects on surface runoff but human disturbance would increase soil erosion and sediment yield on hillslope. This paper provides a reference for vegetation rehabilitation and soil and water loss control on karst hillslope.