Abstract:Different soil and water conservation practices often varied considerably in sediment interceptionand runoff reduction.The cost effectiveness of sediment control can be quantified by the ratio of detainedrunoff and sediment(Rrs).Perennially monitoring data were collected from three typical loess regions(Xifengand Tianshui City in Gansu Province,Suide City in Shaanxi Province)and Rrs were calculated for differenttillage and biological practices.The results showed that the Rrsvaried greatly from 8.5to 36.4m3/t.Fortillage management,contour tillage showed the highest Rrs,followed by level ditch tillage and shallow plowing,while deep plowing had the lowest.For biological managements,the Rrsof intercropping of low-stemand high-stem crops was higher than those of monoculture of low crops and rotation of middle high-stemcrops.The Rrsof pasture(sweet clover,alfalfa)rotation was significantly higher than crop rotation,andsweet clover/crop rotation system was better than alfalfa-crop rotation system in terms of erosion control.With increasing rainfall and slope gradient,Rrsvalues decreased in general.The practice with higher Rrscouldreduce more runoff discharge and increase soil moisture content with similar performance in sediment control.