Respose Of Grassland And Livestock To Baning And Delaying Grazing Systems In Stipa Breviflora Desert-steppe

The study was conducted with two grazing systems of banning grazing,delaying and continue grazing stocking on family ranches in Stipa breviflora desert steppe. Evaluations on the aspects of plant population, community, soil and livestock production performance were made in grassland. The results were as follows:1 The plant community employed better stability and adaptability to environment in the delaying plot than those in the continue plot.The coverage and density of perennials plant were high in the continue plot and delaying plot of period of 40-50 days.Difeerent delaying grazing could improve several indexes that were better than continue grazing.However, the effect on delaying grazing didn't come into being positive ratio with time.Perennials plant keep more important value banning and delaying grazing systems.However, the important values of Enneapogon borealis and Salsola collina of annuals plants played an important role in banning grazing area.2 The standing crop of community in banning grazing area was obviously higher than the rest area. Meantime, it was higher in different delaying grazing areas than the continue grazing area.3 There was significant impact on the soil water content of 10-40cm layers, but little effect on the topsoil. Banning and delaying grazing systems could increase soil water content, it did come into being positive ratio with delaying grazing time. The soil bulk declined as the period of the delaying grazing increased. The soil bulk was lower in the free grazing than that in the delaying grazing.4 There was a positive correlation between the above-ground standing crop and soil water content of 0-30cm layers in the Stipa breviflora Desert Steppe.5 Body weight gain of sheep was directly proportional to the period of delaying grazing. Especially, from July to September sheep daily gain further reflected the superiority of delaying grazing system. 6 From the point of view of the standing crop of community and content of forage, the delaying grazing of period of 40-50 days was reasonable.