基于RUSLE模型的湟水流域土壤侵蚀时空变化

研究黄河上游土壤侵蚀的时空变化对于维持黄河上游生态系统服务功能、保护黄河上游水塔具有重要意义。以黄河上游典型区域湟水流域为研究区,采用RUSLE模型定量评估了该流域2000—2015年土壤侵蚀的时空变化特征,并分析了有无梯田措施下土壤侵蚀的空间变化,从而量化了梯田建设对防治坡面土壤侵蚀的影响。结果表明:2000—2015年,湟水流域的土壤侵蚀强度整体呈现减小趋势,侵蚀模数由1 183 t/(km~2·a)降低至940 t/(km~2·a),减少幅度为20.54%。不同土地利用类型以及不同坡度下的土壤侵蚀强度均有所降低,其中耕地上的减幅最大为20.58%。15°～20°坡度区间的侵蚀模数减幅最显著,为23.11%。通过有无梯田措施情景模拟发现,湟水流域2015年土壤侵蚀模数由940 t/(km~2·a)降低至有梯田的837 t/(km~2·a),减少11.00%。研究结果可为流域的水土流失防治和生态环境保护提供科学依据。

Spatial-Temporal Change of Soil Erosion in Huangshui Watershed Based on RUSLE Model

The research on the temporal and spatial change of soil erosion in the upper reaches of the Yellow River is of great significance to maintain the ecosystem service function and protect the water tower in the upper reaches of the Yellow River. Taking Huangshui watershed in the upper reaches of the Yellow River as the research area, based on the Revised Universal Soil Loss Equation (RUSLE), the spatial and temporal variation of soil erosion in Huangshui watershed from 2000 to 2015 were quantitatively evaluated, and the spatial variation of soil erosion with or without terraced fields were analyzed, so as to quantify the impact of terrace construction on slope soil erosion. The results showed that from 2000 to 2015, the soil erosion intensity in the Huangshui watershed showed a decreasing trend, and the erosion modulus decreased from 1 183 t/(km²·a) to 940 t/(km²·a), with a decrease rate of 20.54%. The soil erosion intensities on different land use types and different slopes all decreased, among which the maximum reduction was 20.58% on cultivated land. The erosion modulus of the slope with 15° to 20° gradient decreased most significantly by 23.11%. Through scenario simulation with or without terrace measures, it was found that the soil erosion modulus in 2015 in the Huangshui watershed decreased from 940 t/(km²·a) to 837 t/(km²·a) with terraced fields, with a decrease of 11.00%. The research results could provide a scientific basis for the prevention and control of soil erosion and the protection of ecological environment of the basin.