【摘要】 借助我国土壤侵蚀普查数据,利用土壤侵蚀综合指数(EI)进行各级侵蚀强度的综合量化,同时结合典型流域的实测数据和重点工程所在县的监测资料,从红壤全区、重点工程县和典型流域3个尺度进行水土流失治理成效评估。结果表明:1)近10年来南方红壤区土壤侵蚀面积呈减少趋势,共减少0. 5万km2,不同等级的侵蚀面积变化趋势各不相同,中度侵蚀面积明显减少,而轻度侵蚀面积显著增加。从省级变化趋势来看,江西、湖北等6省土壤侵蚀程度有所减轻,而广西、广东等4省区的土壤侵蚀状况有加重趋势。2)从177个重点工程县的EI来看,有112个县土壤侵蚀程度减轻,占63. 3%。其中,生态文明工程县EI平均值减幅最大,水土流失治理成效最显著,其次是国家重点治理区、科技示范园和清洁小流域所在县。从分布片区来看,赣南、湘中、皖西及浙闽沿海各县土壤侵蚀状况有不同程度的好转,而湘南、皖南山区和粤东沿海各县有局部加重趋势。3)从典型流域尺度来看,近几十年来江河流域径流量随时间的推移有轻微上升趋势,但输沙量显著下降,且随着小流域内植被覆盖率和农民人均纯收入的不断增加,其平均土壤侵蚀模数也呈下降趋势。本研究结果从不同尺度揭示了南方红壤区的水土流失治理成效,明确了区内不同类型工程的水土流失成效状况,对今后的水土保持布局有借鉴意义。更多还原

【Abstract】 [Background]The red soil region is one of the eight soil and water conservation districts in China,and it is an important production base for grain,oil,crop and timber. Soil and water erosion process in this area is complicated and difficult to be controlled,thus comprehensive managements are needed. Reasonable analysis of the effects of these managements in easing erosion is important to soil and water conservation planning. [Methods]This study was conducted based on the data from two national soil erosion surveys( Ministry of Water Resources 2002,2011),and erosion indexes( EI) were calculated to quantify soil erosion risk. Field measured data from typical watersheds and key project counties were also adopted to analyze the effects of comprehensive harness in soil and water erosion from multi-scales. Besides,EI is a comprehensive index value based on the quantitative classification of soil erosion area and total land area in a unit,and weight transformation. [Results]1) Soil erosion area in the whole region declined by 5 000 km2 recently with the moderate erosion level contributed the most.However,the erosion area of the light level increased. Generally,the soil erosion risk in Jiangxi,Hubei,Zhejiang,Fujian,Hunan and Anhui provinces have been controlled at different degrees. Nevertheless,the erosion risk in Guangxi,Guangdong,Hainan and Jiangsu provinces still need to be improved. 2)From the perspective of 177 key project counties,the soil erosion risk of 112 counties had a downward trend,accounting for 63. 3%. Among them,the average value of EI in ecological civilization project declined the most,followed by national key prevention and control region,technology demonstration parks and clean small watersheds. From the aspect of distribution area,those in southern Jiangxi,central Hunan,western Anhui,Zhejiang and Fujian coastal counties showed obvious efficiency in erosion controlling. The counties in southern Hunan,southern Anhui and eastern Guangdong are still suffering relatively high erosion risk. According to national key prevention and control regions,erosion area and EI in upstream protection region of Xiang River,Zi River,Yuan River,and Li River and upstream protection region of Dong River increased obviously. 3) In the watershed scale of typical rivers,the runoff showed an inconspicuous upward trend during the past decades,while the sediment showed a significant declining trend. On the other hand,with the increase of vegetation coverage and the per capita net income of farmers,the average soil erosion modulus in the small watersheds also descended. Both indicated that the soil and water erosion control in the region has achieved remarkable results.[Conclusions]After years of treatment,the soil and water erosion risk in the region showed a general improvement and partial deterioration. The results revealed the effects of soil and water erosion control from different scales,which are of great significance for future soil and water conservation layout in the red soil region.更多还原