Study On The Effection About Plant Community Characteristics Among Different Time Of Rest-Grazing On Leymus Chinensis Pasture

The research was carried out at National Grassland Ecosystem Field Researeh Station inHebei Province for two years from 2007 to 2008. Study on the utilize of vegetation Rest-Grazing on Leymus Chinensis Pasture. Setted up 27 Rest-Grazing enclosure on which were symmetrical vegetation and almost consistent terrain were chosen to set up research sites. To carry out different time of Rest-Grazing. Observate and Study on which was aimed at the correspondence of the community and main population towards different time of Rest-Grazing. The characteristics of vegetative succession on level of community were analyzed.In order to Provide some seientific basis for Proteeting and managing grassland in Bashang area. Offer the strategy on continuably utilize of Leymus Chinensis Pasture and theoretics means of Rest-Grazing. Theresults indieate:1. The biomass of mostly vegetation in enclosures which Rest-Grazing 40d in Autumn and 60d last year obviously higher than that in Free-Grazing(P<0.05).And the biomass of Artemisa eriopoda in Free-Grazing was higher . It was propitious to enhanced the biomass of Leymus Chinensis in spring Return-Green which Rest-Grazing 60d in Autumn of last year. But other vegetative succession was higher in Rest-Grazing 40d in Autumn. And it was come to in the middle of time of vegetation growth , there was no obviously change of the biomass of vegetative succession. But the biomass of mostly accomply vegetation has obviously increased in enclosures. The biomass of Artemisia tanacetikolia was higher in Free-Grazing.2. The height of Leymus Chinensis,Agpropyron cristatum,Cleistogenes squarrosa,Taraxacum mongolicum,Artemisa eriopoda vegetative succession in enclosures was obviously higher than that in Free-Grazing(P<0.05). And the height of Stipa krylovii Roshev.in enclosures which Rest-Grazing 40d in Autumn last year was obviously higher than that in Free-Grazing(P<0.05). But at it is come to in the middle of time of vegetation growth , there was no obviously change of the biomass of vegetative succession for cattle grazing. The height of Taraxacum mongolicum and Stipa krylovii Roshev. in enclosures which Rest-Grazing 75d in Spring and Rest-Grazing 60d in Autumn was obviously higher than that in Free-Grazing(P<0.05).3. There was no obviously changes about underground biomass of differents Time of Rest-Grazing. It was hihghest for the underground biomass of vegetation in Free-Grazing.The underground biomass of 10-20cm underground in the middle and last time of vegetation growth was higher than that in Free-Grazing. The underground biomass of Leymus Chinensis's root in Free-Grazing was higher, and was improving in the middle of vegetation growth ,but declined at last time of vegetation growth. The long of Chinensis's root and number of root burl was higher in Free-Grazing, and it was hihghest at last time of vegetation growth in the enclosures which Rest-Grazing 75d in Spring and Rest-Grazing 60d in Autumn ,and was obviously higher than others(P<0.05).4. The density of Leymus Chinensis and other perennial vegetations was higher than that in Free-Grazing in spring Return-Green time,but the density of Artemisa eriopoda was lower in enclosures. The density of Leymus Chinensis,Agpropyron cristatum,Cleistogenes squarrosa,Stipa krylovii Roshev vegetative succession in enclosures was obviously than others. But the density of vegetative succession in Free-Grazing was improved. There was no obviously change of the coverage of vegetative succession . the coverage of Agpropyron cristatum vegetative succession has improved.5. The important value of Leymus Chinensis in enclosures which Rest-Grazing 60d in Autumn last year was higher than that in Free-Grazing . The Margalef index and Pielou index which Rest-Grazing 75d in Spring and Rest-Grazing 60d in Autumn was higher than that in Free-Grazing but the Simpson index Shannon-Wiener index was lower. But there was no obviously change about that. It was indieated that the in enclosures which Rest-Grazing 75d in Spring and Rest-Grazing 60d in Autumn was suitable for Sai Bei area.The biomass and height of vegetative succession was higher than others, and so do the density and coverage .