固原试区综合治理减沙效益观测初报

固原县上黄试区径流小区建立4年来，获得37次起流降雨记录，共1272个数据；还建立了综合治理与不治理的对比观测区，1988年也获得记录。经初步整理，得出坡度、坡长、不同植被、不同雨强与水土流失量的关系，如坡度大于25°时，流失量并不一定随坡度的增加而增加；坡长在40m时，流失量达最大值；草灌乔地土壤流失量较农地减少60—90%以上；不同雨强对流失量影响极大。对比观测区初步结果是综合治理的比不治理的减沙83.3%；根据小区数据估算，全试区15km²减沙61.0%。

The Preliminary Report on Observing Efficiencies of Silt Decreasing in Comprehensive Controlling,Experimental and Exemplary Area,Guyuan County

Since the runoff plots were established four years ago on Shanghuang Experimental and Exemplary Area, Guyuan County, there were 37 records of runoff-rain and 1272 figures of runoff being obtained.And in 1988, the observing area of comprehensive controlling and no controlling on silt decreasing was also established.Here is a preliminary report about the slope, length of slope, different vegetation cover, different rainfall intensity and soil erosion, For example, when the slope is >25°，the soil erosion uncertainly increases togather with slope increasing; when the length of slope is 40m, the soil erosion reaches maximum; the lands of grasses, shrubs and trees have been less 60-90% or more than corp lands; the effect of rainfall intensity on soil erosion is very tremendous; the soil erosion of comprehensive controlling area has decreased 83.3% than no controlling area; based on the data of runoff plots soil erosion of all experimental area (15km²) was estimated that it has decreased more than 60%.