生态建设显著改变了黄土高原的下垫面状况和水动力格局,深刻影响了坡沟系统的侵蚀和泥沙来源.以黄土高原丘陵沟壑区高西沟流域为研究对象,基于Landsat TM和Landsat OLI影像,利用遥感解译和地理信息系统方法,分析了高西沟流域沟间地、沟谷地的NDVI和土地利用时空变化特征,并在此基础上研究了流域沟间地和沟谷地土壤侵蚀量的变化.结果表明:2000-2018 年沟间地和沟谷地NDVI均有所增加,低等级NDVI(<0.2)面积减少,较低等级NDVI(0.2～0.4)和中等级NDVI(0.4～0.6)面积增加;沟间地和沟谷地林草地面积均有所增加,流域土地利用结构变化主要为耕地向林草地转化;沟间地平均植被覆盖度由57%增加至71%,沟谷地平均植被覆盖度由60%增加至71%;流域土壤侵蚀面积由3.81 km2 下降到1.77 km2,减少了38%,年土壤侵蚀量由3.64×104 t下降至1.39×104 t,降低了62%;沟间地年土壤侵蚀量减少了68%,沟谷地年土壤侵蚀量减少了47%.
The Impact of Ecological Construction on Vegetation Coverage and Erosion of Slope and Gully Systems in Watersheds in Hilly and Gully Areas of the Loess Plateau
Ecological construction has significantly changed the underlying surface conditions and hydrodynamic pattern of the Loess Plat-eau,and profoundly affected the erosion and sediment sources of the slope-gully system.Taking the Gaoxigou watershed in the hilly and gully area of the Loess Plateau as the study object,based on Landsat TM and Landsat OLI images,and using remote sensing interpretation and geographic information system methods,the NDVI and land use variation with time and space of the inter-ravine land and ravine land in the Gaoxigou watershed are analyzed.Based on the analysis,the changes in soil erosion amount in the inter-ravine land and ravine land of the watershed are studied.The results show that:from 2000 to 2018,NDVI increased in both inter-ravine land and ravine land,the area of low-grade NDVI(<0.2)decreased,and the area of low-grade NDVI(0.2～0.4)and mid-grade NDVI(0.4～0.6)in-creased;The areas of forest and grassland in inter-ravine land and ravine land have increased,and the change in land use structure in the watershed is mainly the conversion of cultivated land to forest and grassland;the average vegetation coverage in inter-ravine land has increased from 57%to 71%,and the average vegetation coverage in ravine land has increased from 60%to 71%.The area of soil erosion in the watershed decreased from 3.81 km2 to 1.77 km2,a decrease of 38%,and the annual soil erosion volume decreased from 3.64×104 t to 1.39×104 t,a decrease of 62%,and the annual soil erosion in the inter-ravine land has been reduced by 68%,and the annual soil erosion in the ravine land has been reduced by 47%.
万方数据
维普
