| Land is the basic natural resource that human beings depend on.As the contradictions between human and the environment becoming more and more serious,land protectionhas become a focus.Due to soil erosion causes a range of environmental problems,threatening the co-ordination of society and economy,water and soil conservation has attracted much attention.In recent decades,“3S”technology developed rapidly,using “3S”technology buildingsoil erosion model is significance for soil erosionand soil conservation quantityreseach.Using“3S”technology,combined with universal soil loss equation model,based on the southern slope of Qilian MountainsDEM data,Landsat data,soil type map of Qinghai province and rainfall data of southern slope of Qilian Mountains,this paper made a soil conservation quantityevaluation of the southern slope of Qilian Mountains from 2004 to 2014,calculatingthe soil conservation quantity and soil erosion quantity of 2004,2009 and 2014 separately,and discussing the relationship between soil erosion,soil conservation and elevation,slope,vegetation coverage and landuse.The results showed that:(1)The soil erosion is mainly occurred at region which elevation is range within 4000 ～ 5000 m.The vegetation coverage of region which slope is around25° is middle coverage area.The soil erosionquantity of research area has significant correlation with slope,vegetation coverage and elevation.The level and quantity of soil erosion rises with the increasing of elevation and slope while declines as vegetation coverage increases.The interannual variation of actual soil erosionquantity showed a trend of decrease in general.(2)The interannual average soil conservationquantityand soil conservationquantity showed a increasing trend from the aspect of vegetation coverage(middle vegetation coverage,middle-high vegetation coverage,high vegetation coverage),elevation and slope.The average quantity of erosionmodulus rises with the increasing of slope and vegetation coverage while declinesaselevation falling.The largestsoil conservationquantity is in the elevation belt of 3000～4000m,slope above 8° and high vegetation coverage area.The ecological management of those area should be enhenced to make a better ecological environment.(3)The woodland and grassland are the main body of ecological system in the southern slope of Qilian Mountains.We should focus on the protection of woodland and grassland ecosystem that is in the elevation belt of 3000～4000m or region which slope is above 8° to stabilize the tatol soil conservationquantity of research area.The soil erosion quantity of passed 10 years has been declining.The actual soil erosion quantity of the year 2004,2009,and 2014 was 2.11×107t/a 、2.48×107t/a 、1.54×107t/a.The soil conservation quantity has been increasing.The soil conservation quantity of the year 2004,2009,and 2014 was 1.20×107t/a 、1.86×107t/a 、3.71×107t/a.That shows the ecological environment of the southern slope of Qilian Mountains is improving. |
