Slope shape as a consequence of erosional landform development plays a prominent role in soil erosion. Clarifying the distribution of soil erosion and deposition patterns on different shaped slopes is crucial for soil erosion control. The aim of this study was to decipher the effects of slope shape on soil erosion and deposition patterns under natural rainfall conditions based on high-resolution unmanned aerial vehicle (UAV) data and geographic information system technology. Structure from motion (SfM)-UAV photogrammetry was carried out in four runoff plots with various slope shapes during the rainy season in 2021. Digital elevation models (DEMs) were developed for each slope shape before and after the rainy season. In addition to collecting runoff and sediment, the DEMs of difference were analyzed to quantify soil erosion and deposition patterns on various slope shapes in the rainy season. Results showed that the runoff volumes and sediment yields induced by rainfall were markedly different among various slope shapes. The mean runoff volume and sediment yield from the concave-convex slope were 1.09 ∼ 2.69 and 1.33 ∼ 27.16 times those of the other three slopes, respectively, with less sediment loss from the convex-concave slope and its combination slope. Slope shape exhibited a notable effect on the type of slope erosion and deposition. All four slopes showed considerable changes in surface elevation after the rainy season. The increase and decrease in surface elevation were concentrated in the range of –0.02 to –0.007 m and 0.007 to 0.02 m, respectively, with a low proportion of changes less than –0.03 m and greater than 0.03 m. The effectiveness of SfM-UAV in monitoring the microgeomorphic changes of slopes was verified by the consistency of soil erosion amounts based on sediment collection and SfM-UAV measurements. Reference values were provided to solve the threshold problem of slope length cutoff in soil erosion prediction models based on runoff plot experiments. Findings of this study could be useful for decision-making in soil erosion control and slope reconstruction.

中文翻译：

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基于SfM-UAV摄影测量的坡形对土壤侵蚀和沉积模式的影响


侵蚀地貌发展导致的坡形在土壤侵蚀中起着突出的作用。阐明不同形状边坡上土壤侵蚀和沉积模式的分布对于土壤侵蚀控制至关重要。本研究旨在基于高分辨率无人机 （UAV） 数据和地理信息系统技术，破译自然降雨条件下坡形对土壤侵蚀和沉积模式的影响。在 2021 年雨季期间，在 4 个不同坡形的径流样地中进行了运动结构 （SfM）-无人机摄影测量。为雨季前后的每种坡度形状开发了数字高程模型 （DEM）。除了收集径流和沉积物外，还分析了差异的 DEM，以量化雨季各种斜坡形状上的土壤侵蚀和沉积模式。结果表明，不同坡型间降雨引起的径流量和产沙量存在显著差异。凹凸坡的平均径流量和产沙量分别为其他3个边坡的1.09 ∼ 2.69和1.33 ∼ 27.16倍，凸凹坡及其组合坡的泥沙损失较少。坡形对边坡侵蚀和沉积类型表现出显著影响。雨季过后，所有四个斜坡的地表高程都显示出相当大的变化。地表高程的增加和减少分别集中在 –0.02—–0.007 m 和 0.007—0.02 m 范围内，小于 –0.03 m 和大于 0.03 m 的变化比例较低。 通过基于沉积物收集和 SfM-UAV 测量的土壤侵蚀量的一致性验证了 SfM-UAV 监测边坡微地貌变化的有效性。为解决基于径流样地试验的土壤侵蚀预测模型中坡长截断的阈值问题提供了参考值。本研究结果可为水土流失控制和边坡重建的决策提供参考。