Abstract: The response of plant coverage, aboveground and belowground biomass, and species richness of different types of grassland(elm scattered grassland, Stipa steppe and meadow)in Horqin sandy land for the exclosure and grazing were studied. The results showed that dominant plants in fencing grassland were perennial grasses, while annual and sub-shrub in grazing grassland. The vegetation coverage, litter biomass, aboveground biomass and species richness in three types of grassland under fencing and grazing had significant difference (P<0.05), of which enclosure significantly increased their coverage and aboveground biomass that added from to elm scattered grassland to Stipa steppe to meadow. The litter biomass of grassland being fenced added in the following order: Stipa steppe>elm scattered grassland>meadow. The differences of coverage, litter biomass and species richness of different grazing grassland were non-significant(P>0.05).The root biomass between three grassland had non-significant difference(P>0.05), which significantly different between exclosure and grazing, different soil depth. The exclosure significantly increased root biomass of grassland. The long-term grazing increased the advantages of annuals and small sub-shrubs, eliminated the differences of plant coverage and species richness between three grasslands. The exclosure can raise the dominance of perennial grasses, increase their species richness, and have a positive effect on recovery and conservation of grassland quality and plant diversity.

Key words: Horqin Sandy Land, species diversity, biomass, root, dominant species