黄河流域十大孔兑土地利用变化的土壤侵蚀效应

Effects of land-use changes on soil erosion in Ten Tributaries of the Yellow River Basin

十大孔兑位于黄河流域上游内蒙古段,降雨季节易形成峰高量大、含沙量高的洪水涌入黄河,水力侵蚀与风力侵蚀并存,侵蚀情况复杂。采用修正土壤流失方程与地理空间分析技术,分析了十大孔兑地区1990-2015年土地利用变化的土壤侵蚀效应。分析结果表明:1990-2015年,研究区域林地面积明显增大,由2.18万hm^(2)增至24万hm^(2)。草地面积先上升后下降,由53.8万hm^(2)先升至58.2万hm^(2),后降至51.0万hm^(2)。十大孔兑地区土壤侵蚀模数上升后显著降低,由10.26 t/hm^(2)·a先升至18.43 t/hm^(2)·a,后降至2.01 t/hm^(2)·a,中度以上侵蚀面积从2.85万hm^(2)降至0.42万hm^(2),以微度和轻度侵蚀为主。十大孔兑地区土壤侵蚀状况明显改善,尤其在2000年后,伴随大规模的生态工程建设,对区域水土流失治理发挥显著作用。

The situation of soil erosion at Ten Tributaries of the upper Yellow River is complex due to the coexist of hydraulic erosion with wind erosion,and thereby floods with high peaks and high sediment concentration tend to flow into the Yellow River during the rainy season.The effects of land use changes on soil erosion in Ten Tributaries of the upper Yellow River from 1990 to 2015 were analyzed by using the Revised Universal Soil Loss Equation(RUSLE)model and GIS spatial analysis technology.The results show that:from 1990 to 2015,especially after 2000,the area of forestland in the study area increased significantly,from 21765 ha to 240280 ha,the area of grassland increased slightly from 537623 ha to 582369 ha and then decreased to 509599 ha,the soil erosion module sharply decreased from 18.43 t to 2.01 t per hectare per year,and the soil erosions were mainly in slight and light level.This indicates that the soil erosion situation in the Ten Tributaries area has improved significantly,especially after 2000,with the large-scale ecological engineering playing a significant role in regional soil erosion control.