基于模拟降雨试验的喀斯特坡耕地土壤侵蚀特征

Characteristics of soil erosion on Karst slopes under artificial rainfall experiment conditions

探索喀斯特坡耕地土壤侵蚀过程及机理对该区水土流失及石漠化治理具有重要的现实和指导意义.本文采用人工模拟降雨的试验方法,探索喀斯特坡耕地土壤侵蚀过程及特征.结果表明:降雨强度较小时(30、50 mm·h^(-1)),水土流失以地下孔(裂)隙流失为主,当降雨强度较大时(80 mm·h^(-1)),土壤侵蚀以地表流失为主;地表径流模数和输沙率均随坡度的增加而增大,随孔(裂)隙度的增加而减小.地下径流模数在0.37~0.52 L·m^(-2)·min^(-1),地下输沙率在0.81~1.93 g·min^(-1),二者均随坡度的增加而减小,随降雨强度的增加呈先增大后减小的变化趋势.

Studying soil erosion process and mechanism on Karst slopes has important practical and guiding significance for controlling soil and water loss and preventing rocky desertification in Karst region. The soil erosion process and characteristics on Karst slopes were explored by artificial simu- lation rainfall experiment. Results showed that the soil and water loss largely came from underground hole （crack） when rainfall intensity was in the range of 30 and 50 mm ~ h-1, while soil erosion oc- curred primarily in soil surface when rainfaU intensity was 80 mm ~ h-l. Surface runoff modulus and transport rate both increased with increasing slope, and decreased with increasing underground hole （crack） degree. The underground runoff modulus varied from 0.37 to 0.52, and the underground transport rate changed from 0.81 to 1.93 g · min-1. They both decreased with increasing slope while increased firstly and then decreased with increasing rainfall intensity.