基于RUSLE模型的青藏高原土壤保持功能定量评价

土壤保持功能是青藏高原生态系统的主要调节功能之一，准确评估青藏高原土壤保持功能的时空变化规律，是确保该地区顺利开展水土保持和生态环境治理工作的前提。本研究通过收集气象、土壤、土地利用、DEM和NDVI等数据，利用RUSLE模型对1982—2020年青藏高原土壤保持功能的时空特征进行动态评估。结果表明：1982—2020年青藏高原的土壤保持量呈波动增加趋势，土壤保持能力由南向北逐渐减弱，高值区主要集中在青藏高原东南部的川西和藏东的高山深谷；在过去的近40 a中，青藏高原土壤侵蚀强度发生明显转换，其主要特征是由高一级的中度侵蚀强度向低一级的轻度或微度侵蚀强度转换，说明青藏高原近40 a内土壤保持状况不断改善；不同地形条件下青藏高原土壤保持能力也有明显差异，主要表现为起伏度小的高海拔地区土壤保持能力普遍较弱；就不同的土地利用类型而言，林地区域的土壤保持能力最强，而未利用地土壤保持能力最弱。近40 a来，青藏高原土壤保持能力不断增强，但仍存在部分区域的土壤保持能力较弱。未来在重视和保护土壤保持能力较强的林地区域的同时，应加强起伏度小的高海拔地区水土治理工作，制定分级分区的土壤侵蚀防治措施，进一步增强青藏高原地区的土壤保持功能。

Quantitative Evaluation of Soil Conservation Function in the Qinghai-Xizang Plateau Based on RUSLE Model

Soil conservation function is one of the main regulating functions of the ecosystem of the Qinghai-Xizang Plateau, and the accurate assessment of the spatial and temporal change pattern of soil conservation function on the Qinghai-Xizang Plateau is a prerequisite to ensure the successful implementation of soil and water conservation and ecological environment management in the region. In this study, the meteorological, soil, land use, DEM and NDVI data were collected, and the dynamic changes of spatial and temporal characteristics of soil conservation function on the Qinghai-Xizang Plateau from 1982 to 2020 were assessed by using the RUSLE model. The results indicated that soil retention showed a fluctuating increase from 1982 to 2020, and soil retention intensity gradually decreased from south to north, with the high value areas mainly concentrated in the high mountain valleys of western Sichuan and eastern Xizang in the southeastern part of the Qinghai-Xizang Plateau; soil erosion intensity showed a significant transformation in the past 40 years, mainly characterized by the transformation from a high level of moderate erosion intensity to a low level of mild or slight erosion intensity, indicating a significant transformation from a high level to a low level in soil erosion intensity. The main characteristic was the conversion from high moderate erosion intensity to low mild or slight erosion intensity, indicating the improvement of soil conservation condition in the past 40 years; soil conservation capacity also was obvious different under different topographic conditions, which mainly was weaker in the high altitude areas with small degree of undulation; in terms of soil conservation capacity under different types of land use, the forest area was the strongest while the unused land was the weakest. Over the past 40 years, soil conservation capacity was increased, but some areas still faced weak soil conservation capacity. For the further enhancement of soil conservation function of the Qinghai-Xizang Plateau in the future, while paying attention to and protecting forest with strong soil conservation capacity, soil and water management should be strengthened in high-altitude areas with little undulation, and soil erosion prevention and control measures should be formulated on a hierarchical and zonal basis.