祁连山南坡土壤侵蚀时空变化及迁移特征分析

Analysis of the Spatial and Temporal Changes and Migration Characteristics of Soil Erosion in the South Slope of Qilian Mountain

土壤侵蚀是威胁人类生态环境及社会经济的重要因子。为实现土地资源更加有效的保护与治理,基于RUSLE模型和GIS/RS空间信息技术,分析和讨论了祁连山南坡2000—2019年土壤侵蚀时空变化及土壤侵蚀重心迁移特征。结果表明:祁连山南坡土壤侵蚀模数在空间变化上整体呈现出由西北向东南递减的趋势,土壤侵蚀模数平均值由2000年的1966.63 t/(km^(2)·a)增加至2005年的3228.51 t/(km^(2)·a),最后下降至2019年的2299.06 t/(km^(2)·a);草地土壤侵蚀量最大,为2.65×10^(7)~4.25×10^(7)t/a,虽侵蚀较为严重,但土壤侵蚀重心并未发生较大的迁移,五县中祁连县土壤侵蚀最为严重且重心迁移距离最大,侵蚀量为3.01×10^(7)~4.83×10^(7)t/a,共迁移351.89 m,迁移速率为17.59 m/a,说明祁连县土壤侵蚀不稳定,土壤低级侵蚀更容易向高级侵蚀转化;土地利用类型中冰川迁移最大为367.78 m,迁移速率为18.39 m/a。综合得出,对于土壤侵蚀较轻且重心迁移不大的区域可以采取定点治理,对于祁连县应长时间监测,全力推进祁连县水土保持综合治理工程,缓解水土流失;相较于其他生态系统,对于草地与林地应加强治理。

Soil erosion is an important factor that threatens human ecological environment and social economy.In order to achieve more effective protection and management of land resources,based on the RUSLE model and GIS/RS spatial information technology,we analyzed and discussed the temporal and spatial changes of soil erosion and the migration characteristics of soil erosion gravity center on the southern slope of Qilianshan Mountains from 2000 to 2019.The results show that the soil erosion modulus on the southern slope of Qilianshan Mountain presented a decreasing trend from northwest to southeast in terms of spatial variation;the average soil erosion modulus increased from 1966.63 t/(km^(2)·a)in 2000 to 3228.51 t/(km^(2)·a)in 2005,and finally dropped to 2299.06 t/(km^(2)·a)in 2019;the amount of grassland soil erosion was the largest,which was 2.65×10^(7)~4.25×10^(7)t/a,although the erosion was relatively serious,the center of gravity of soil erosion did not move significantly;among the five counties,Qilian County had the most severe soil erosion and the largest migration distance of the center of gravity;the amount of erosion was between 3.01×10^(7) t/a and 4.83×10^(7)t/a,the total migration was 351.89 m,and the migration rate was 17.59 m/a,indicating that soil erosion in Qilian County was unstable,and low-grade soil erosion easily transformed into high-grade erosion;the largest glacier migration in land use types was 367.78 m,the migration rate was 18.39 m/a.It is concluded that fixed-point treatment can be adopted for areas with less soil erosion and little center of gravity migration,and Qilian County should be monitored for a long time,and the comprehensive treatment project of soil and water conservation in Qilian County should be fully promoted to alleviate soil erosion.Compared with other ecological system,the grassland and forestland should be strengthened.