Survey on the Effects of Management Alteration on Grassland in Agropastural Ecotone of North China

Method of sampling plot has been used to investigate treatment effects of different management categories on grassland in Yanchi,Ningxia Hui Autonomous Region.Six kinds of grasslands have been selected,which were early-time enclosed grassland(E),middle-time enclosed grassland(E1),newly enclosed grassland(E2),natural grassland(TR),grain for green land(TG) and abandoned land(LH).On the basis of important value,evaluation in improvement of grassland environment has been done through α-diversity index,β-diversity index and biomass effectiveness.The results showed that:(1) due to little human disturbances,natural grassland performanced the best in terms of SW-diversity index and SP-dominance index compared with the others,and grain for green land has the biggest evenness index;(2) on the study of grassland similar test,community composition of grain for green land was most likely to natural grassland;(3) based on the study of biomass,grain for green land achieves the highest biomass,biomass of natural land was ranked as the second.Among fencing grasslands,early-time enclosed grassland had the lowest aboveground biomass.As a result,fencing and grain for green were effective methods to generate grassland restoration.As fencing time went by,grassland came to degradation with the sign that diversity indices turn to decrease compared with early time.Method of grain for green behaved significantly better than fencing.