植被斑块格局对砒砂岩坡面土壤侵蚀强度的影响

选取水力侵蚀极其剧烈的砒砂岩区为研究对象,基于野外径流小区的连续监测试验,采用三维激光扫描、无人机航拍与方差均值比率法相结合,对比分析砒砂岩坡面3种典型自然植被格局(聚集分布、均匀分布、随机分布)下的产流产沙特征与坡面微地形的演变规律。结果表明:(1)均匀分布格局对减缓水力侵蚀条件下砒砂岩坡面土壤侵蚀强度的效果最明显,与裸坡相比,减流率达到64%,减沙率达到72%,土壤流失量最少,为0.05 kg/m²。径流泥沙量之间存在多项式曲线关系,拟合函数为y=-0.0462X²+0.5355X-0.865,R²=0.736。(2)均匀分布格局的侵蚀区面积最小,为12.28 m²;沉积区面积最大,为3.44 m²,土壤侵蚀强度较其他坡面弱,以轻度侵蚀为主。(3)均匀分布格局的径流泥沙量与平均沉积深度之间的相关性较强,与径流量呈显著正相关(p＜0.05),相关系数为0.603;与泥沙量呈极显著正相关(p＜0.01),相关系数为0.771。

Effect of Vegetation Patch Pattern on Soil Erosion Intensity on Arsenic Sandstone Slope

The arsenic sandstone area with extremely severe hydraulic erosion was selected as the research object. Based on continuous monitoring experiments of runoff plots in the field, 3D laser scanning, UAV aerial photography and variance-mean ratio method were used to compare and analyze the characteristics of flow and sand production and the evolution of slope microtopography under three typical natural vegetation patterns (aggregated distribution, uniform distribution and random distribution) on arsenic sandstone slopes. The results showed that: (1) The uniform distribution pattern had the most obvious effect on mitigating soil erosion on arsenic sandstone slopes under hydraulic erosion conditions, with a flow reduction rate of 64%, a sand reduction rate of 72%, and the lowest soil loss of 0.05 kg/m² compared was bare slopes. There was a polynomial curve relationship between runoff and sediment volume, and its fitting function was y=-0.0462X²+0.5355X-0.865, R²=0.736. (2) The erosion area of the uniform distribution pattern was the smallest, which was 12.28 m², and the deposition area was the largest, which was 3.44 m², and the soil erosion intensity was weaker than other slopes, mainly light erosion. (3) The correlation between runoff sediment volume and average deposition depth of uniform distribution pattern was strong, with a significantly positively correlated with runoff volume (p<0.05), and the correlation coefficient was 0.603, and had a highly significant positive correlation with sediment volume (p<0.01), and the correlation coefficient was 0.771.