基于土壤侵蚀指标的黑龙江省重点小流域治理优先序探讨OA

Taking the two national key soil erosion control areas in Heilongjiang Province,namely the rolling hilly region of Northeast China and the eastern piedmont of the Greater Khingan Mountains,as study areas,this paper focused on the management priority of key small watersheds based on soil erosion indicators.Indicators including the proportion of areas with moderate and severe soil erosion,gully density,proportion of areas with slopes larger than 8°,and vegetation coverage were classified by adopting the natural breakpoint method.From the dual dimensions of current soil erosion status and potential soil erosion risk,the priority order of key small watersheds was determined by conducting priority grade comparison.The results show that in the two studied areas,the quantitative ratio of small watersheds classified as extremely urgent,urgent,and moderately urgent for management is approximately 3︰12︰5.There are significant differences in the area distribution of small watersheds with different management priorities.The interquartile range,expected value,and median of the watersheds all follow the order:moderately urgent>urgent>extremely urgent.In both areas,the small watersheds classified as extremely urgent for management account for a small total area yet contain a large share of erosion gullies.Their average gully density is far higher,while the average soil and water conservation rate is considerably lower than those of small watersheds classified as urgent and moderately urgent for management.The delineation of watershed management priorities can provide theoretical reference for carrying out differentiated comprehensive soil erosion treatment and improving the soil and water conservation function of territorial space.