黔中喀斯特坡地浅层裂隙土壤机械组成对降雨的响应

运用野外取样调查结合室内吸管法,分析黔中喀斯特坡地不同土地利用类型浅层裂隙土壤机械组成随降雨的变化特征,以期为该区地下土壤漏失研究提供理论依据和技术支撑.结果表明: 黔中喀斯特坡地浅层裂隙土壤粒径含量总体以粉粒为主,约占57％.在不同降雨量的作用下,坡耕地裂隙土壤颗粒含量变化整体表现为细砂粒含量的减少和粉粒、黏粒含量的增大.草地裂隙土壤颗粒的变化主要是细砂粒含量的减少和黏粒含量的增加.乔木林地和灌木林地裂隙土壤颗粒的变化不规律.降雨量与土壤砂粒含量变化之间存在正相关关系.随着土层深度的增加,各土地利用类型的裂隙对粉粒和极粗砂粒含量的变化有一定影响,其中,粉粒含量随土层深度的增加而减少.

Response of mechanical composition of fractured soil to rainfall in shallow Karst slopes in central Guizhou,China.

Field sampling and indoor pipette method was used to analyze the variation of soil mechanical composition of shallow Karst fissures in response to rainfall under different land uses in Karst rocky desertification region in central Guizhou. Results would supply important scientific basis and direction for further research of soil leakage in the Karst areas. The results showed that silt was the dominant component in soil mechanical composition of shallow Karst fissures, with a content of 57%. In response to rainfall, the contents of silt and clay were increased and that of fine sand was reduced in slope cropland, while the content of fine sand was reduced and that of silt was increased in grassland. The changes of mechanical composition of shallow Karst fissures in forest and shrub land were irregular. Moreover, there was a positive correlation between rainfall and the sand content of shallow Karst fissures. The fissures of land use types had effects on the changes of silt and extremely coarse sand contents with the increase of soil depth, with a decreasing trend of silt.