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为了进一步明确黄土高原水平梯田边坡在不同降雨强度下的侵蚀规律和细沟发育特征,选取陕西安塞县纸坊沟小流域土壤为试验材料,利用自制的试验模型槽,采用人工分层填筑方法,模拟野外最常见的单级梯田形态,在室内模拟降雨的条件下,设计了五组降雨强度(1.5、1.75、2.0、2.25、2.5 mm/min),研究了不同降雨强度对单级梯田的侵蚀规律和细沟发育的影响。结果表明:降雨强度对径流率和侵蚀速率的变化有着显著的影响,雨强≥2.0 mm/min时,径流率和侵蚀速率呈波动性增加;梯田边坡细沟长度、宽度和深度随雨强的增大而增大,其中细沟的长度能很好地反映细沟的发育过程,且与侵蚀速率之间存在着极显著的正相关关系;不同降雨强度下,梯田边坡坡面流速均呈先增大后稳定的趋势,坡面平均流速和雨强呈明显的幂函数关系;梯田边坡在侵蚀分为片状侵蚀、细沟侵蚀、细沟调整和崩塌四个阶段,且土壤侵蚀量与雨强之间有着明显的指数关系。
In order to further clarify the erosion rules and development characteristics of the rill under different rainfall intensities, the soil of the Zongfanggou watershed in Ansai County of Shaanxi Province was selected as the experimental material. Five groups of rainfall intensities (1.5,1.75,2.0,2.25,2.5 mm / min) were designed under the condition of simulated rainfall indoors. The effects of different rainfall intensities on single stage Erosion of terraces and development of rill. The results show that rainfall intensity has a significant effect on the runoff rate and erosion rate. When the rainfall intensity is greater than 2.0 mm / min, the runoff rate and erosion rate increase in a fluctuating manner. The length, width and depth of the terrace slope vary with rainfall intensity The length of the rill can well reflect the development of the rill and there is an extremely significant positive correlation between it and the erosion rate. Under different rainfall intensities, the slope velocity of terrace slope The trend of first increasing and then stabilizing is that the average flow velocity and rainfall intensity have a obvious power function relationship; terrace erosion is divided into four stages: erosion, rill erosion, rill adjustment and collapse, and soil erosion There is a clear exponential relationship between quantity and rain intensity.