Abstract Sheet erosion is common on agricultural lands, and understanding the dynamics of the erosive process as well as the quantification of soil loss is important for both soil scientists and managers. However, measuring rates of soil loss from sheet erosion has proved difficult due to requiring the detection of relatively small surface changes over extended areas. Consequently, such measurements have relied on the use of erosion plots, which have limited spatial coverage and have high operating costs. For measuring the larger erosion rates characteristic of rill and gully erosion, structure-from-motion (SfM) photogrammetry has been demonstrated to be a valuable tool. Here, we demonstrate the first direct validation of UAV-SfM measurements of sheet erosion using sediment collection data collected from erosion plots. Three erosion plots (12 m × 4 m) located at Lavras, Brazil, with bare soil exposed to natural rainfall from which event sediment and runoff was monitored, were mapped during two hydrological years (2016 and 2017), using a UAV equipped with a RGB camera. DEMs of difference (DoD) were calculated to detect spatial changes in the soil surface topography over time and to quantify the volumes of sediments lost or gained. Precision maps were generated to enable precision estimates for both DEMs to be propagated into the DoD as spatially variable vertical uncertainties. The point clouds generated from SfM gave mean errors of ~2.4 mm horizontally (xy) and ~1.9 mm vertically (z) on control and independent check points, and the level of detection (LoD) along the plots ranged from 1.4 mm to 7.4 mm. The soil loss values obtained by SfM were significantly (p

中文翻译：

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使用运动结构对扩散（片状或间纹）侵蚀进行高分辨率监测

摘要 片状侵蚀在农田上很常见，了解侵蚀过程的动态以及土壤流失的量化对于土壤科学家和管理人员都很重要。然而，由于需要在扩展区域检测相对较小的表面变化，因此测量薄片侵蚀造成的土壤流失率已被证明是困难的。因此，此类测量依赖于侵蚀图的使用，其空间覆盖范围有限且运营成本高。为了测量细沟和沟壑侵蚀的较大侵蚀率特征，运动结构（SfM）摄影测量已被证明是一种有价值的工具。在这里，我们展示了使用从侵蚀地块收集的沉积物收集数据对片状侵蚀的 UAV-SfM 测量的首次直接验证。三个侵蚀地块 (12 m × 4 m) 位于巴西拉夫拉斯，裸土暴露在自然降雨中，监测事件沉积物和径流，在两个水文年（2016 年和 2017 年）使用配备有RGB 摄像头。计算差异 DEM (DoD) 以检测土壤表面地形随时间的空间变化，并量化损失或获得的沉积物体积。生成精度地图是为了将两个 DEM 的精度估计值作为空间可变的垂直不确定性传播到国防部。SfM 生成的点云在控制点和独立检查点上的水平 (xy) 平均误差 (xy) 和垂直 (z) 平均误差约为 1.9 mm，沿图的检测水平 (LoD) 范围从 1.4 mm 到 7.4 mm . SfM 获得的土壤流失值显着 (p