Pearl River Hydraulic Research Institute, Pearl River Water Resources Commission, Ministry of Water Resources, Guangzhou, 510611, China.
Soil and Water Conservation Monitoring Center of Pearl River Basin, Pearl River Water Resources Commission, Ministry of Water Resources, Guangzhou, 510611, China.
Environ Monit Assess. 2018 Nov 20;190(12):736. doi: 10.1007/s10661-018-7120-6.
Soil erosion is a major global environmental problem. Therefore, a method of calculating potential soil erosion is necessary for soil and water resource management, as well as for assessing the risk of soil erosion. This study aimed to develop a simple method for calculating potential soil erosion change (PSEC) by combining the Universal Soil Loss Equation (USLE) and a Geographic Information System (GIS). The USLE model includes a rainfall erosivity factor (R), soil erodibility factor (K), cover management factor (C), slope gradient factor (S), length factor (L), and the supporting practice factor (P). Using a measured patch of soil and water conservation as the experimental unit, weather and soil data were combined to calculate R and K. Remote sensing images were used to extract vegetation cover (VC) and calculate C, while digital elevation models were used to extract and calculate S and L; land use maps were used to determine the P of each patch. The PSEC of each patch was then calculated according to the results of the above mentioned six factors. Finally, the PSEC of the entire study area was calculated on the basis of a patch area weighting method, which was validated in the Dacaozi Watershed in China, where a 1-year soil and water conservation project was implemented, beginning in November of 2013. In this study, the PSEC of the Dacaozi Watershed in May of 2017 was calculated, accounting for approximately 3 years of project implementation. The results showed that the average VC increased by 21.6% after 3 years of project implementation, whereas C decreased by 46.4%. The value of P did not change significantly from before to after project implementation. The average S decreased from 22.6 ± 12.1° to 21.3 ± 10.6°, and S decreased by 6.8%. In contrast, L increased by 33.3%. On the whole, the PSEC in the Dacaozi Watershed was 0.3925 and the potential soil erosion decreased by 60.75% after 3 years of conservation.
土壤侵蚀是一个全球性的主要环境问题。因此，为了进行水土资源管理和评估土壤侵蚀风险，有必要开发一种计算潜在土壤侵蚀变化（PSEC）的方法。本研究旨在结合通用土壤流失方程（USLE）和地理信息系统（GIS），开发一种简单的计算潜在土壤侵蚀变化（PSEC）的方法。USLE 模型包括降雨侵蚀力因子（R）、土壤可蚀性因子（K）、植被覆盖和管理因子（C）、坡度坡长因子（S）、和支持措施因子（P）。利用实测水土保持斑块作为实验单元，结合气象和土壤数据计算 R 和 K。利用遥感图像提取植被覆盖（VC）并计算 C，利用数字高程模型提取和计算 S 和 L；利用土地利用图确定每个斑块的 P。然后根据上述六个因子的结果计算每个斑块的 PSEC。最后，根据斑块面积加权法计算整个研究区的 PSEC，并在中国大草滩流域进行验证，该流域于 2013 年 11 月开始实施为期 1 年的水土保持项目。本研究计算了 2017 年 5 月大草滩流域的 PSEC，占项目实施约 3 年的时间。结果表明，项目实施 3 年后，平均 VC 增加了 21.6%，而 C 减少了 46.4%。项目实施前后 P 值变化不显著。平均 S 从 22.6±12.1°下降到 21.3±10.6°，下降 6.8%。相比之下，L 增加了 33.3%。总的来说，大草滩流域的 PSEC 为 0.3925，实施 3 年后潜在土壤侵蚀减少了 60.75%。
