红壤区急陡坡条件下土壤侵蚀研究

发布时间：2019-01-11 15:15

【摘要】：红壤是我国重要的土地资源,由于人为和自然的原因,红壤区存在许多陡坡地甚至急陡坡地,造成红壤区土壤流失严重,生态风险急剧增大。目前我国对于红壤区急陡坡条件下土壤侵蚀特征的认识还不够深入,有待进一步研究。本论文以红壤为研究对象,在室内人工模拟降雨条件下研究了红壤区急陡坡条件下水动力学参数特征、径流侵蚀特征及击溅侵蚀特征,从而进一步认识了红壤区急陡坡条件下土壤侵蚀规律。研究结论如下:(1)在试验坡度范围内水动力学参数变化特征:径流量随坡度的增大而逐渐减少;径流流速随坡度的增加先增加后减少;径流深随坡度的增加而减少;水流流态为层流范畴内的缓流。雨强为60mm/h时径流剪切力随坡度的增加先减少后增加;雨强为90、120mm/h时径流剪切力随坡度的增加先增加后减少再增加。(2)在试验坡度范围内,径流侵蚀量随坡度的变大先减少后增加。击溅侵蚀量在36°以前随坡度变化平缓,基本保持不变,36°以后击溅侵蚀量迅速增加。(3)红壤区急陡坡条件下,随坡度变化土壤侵蚀侵蚀形式发生了变化,36°以前以径流侵蚀为主,36°以后以击溅侵蚀为主。(4)试验研究范围内存在2个临界坡度,一个为极大值临界坡度,一个为极小值临界坡度。雨强为60mm/h时,极小值临界坡度在36°附近;雨强为90、120mm/h时,极大值临界坡度在27°附近,极小值临界坡度在36°附近。
[Abstract]:Red soil is an important land resource in China. Because of man-made and natural reasons, there are many steep slopes or even steep slopes in red soil region, which results in serious soil loss and rapid increase of ecological risk in red soil region. At present, the understanding of the characteristics of soil erosion in red soil region under steep and steep slope conditions is not deep enough and needs further study. In this paper, the characteristics of hydrodynamic parameters, runoff erosion and splash erosion were studied under the condition of artificial rainfall in red soil. Therefore, the law of soil erosion under steep and steep slope conditions in red soil region is further understood. The conclusions are as follows: (1) the variation characteristics of hydrodynamic parameters in the range of experimental slope are as follows: runoff decreases gradually with the increase of slope, runoff velocity increases first and then decreases with the increase of slope, runoff depth decreases with the increase of slope; The flow pattern of water is a slow flow in the range of laminar flow. When the rainfall intensity is 60mm/h, the runoff shear stress decreases first and then increases with the increase of slope. When the rainfall intensity is 90120mm/h, the runoff shear stress increases first and then decreases with the increase of slope. (2) in the range of experimental slope, runoff erosion decreases first and then increases with the increase of slope. After 36 掳, the amount of splash erosion increased rapidly after 36 掳. (3) under the condition of steep slope in red soil area, the soil erosion form changed with the slope. Runoff erosion was dominant before 36 掳and splash erosion after 36 掳. (4) there are two critical slopes in the range of experimental study, one is maximum critical slope, the other is minimum critical slope. When the rain intensity is 60mm/h, the minimum critical gradient is about 36 掳, and when the rain intensity is 90120mm/h, the maximum critical gradient is about 27 掳and the minimum critical gradient is about 36 掳.
【学位授予单位】：江西农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S157.1

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