The Research Of Vegetation Carbon Density,Soil Carbon Density And Nitrogen Density Of Different Coenotypes In Hulun Buir Grassland

Grassland ecosystem is the ecosystem spreading most widely on land. Studying carbon-storage, SOCD and TND in grassland ecosystem is significant to discuss carbon balance, carbon circulating and soil mass in ecosystem, and it also provides for carbon storage and carbon-nitrogen circulating process. According to field investigation and observation, we take the 18 kinds of main coenotype of Hulun Buir typical grassland Polygonum lapathifolium (PZ)?Agropyron cristatum+Leymus chinensis (AgL)?Stipa grandis+ Cleistogenes squarrosa (StC)?Carex duriuscula+ Stipa grandis (CaS)?Cleistogenes squarrosa+Stipa krylovii (CSt)?Allium polyrrhizum+ Stipa grandis (AS)?Artemisia frigida+ Cleistogenes squarrosa (ArC)?Artemisia halodendron+Cleistogenes squarrosa (AC)? Leymus chinesis+Carex duriuscula (LC)?Cleistogenes squarrosa+Agropyron cristatum (CA)?Cleistogenes squarrosa+Stipa grandis (CS)?Leymus chinensis (L)?Stipa grandis+Leymus chinensis (SLe)?Artemisia halodendro+Leymus chinesis (AL)?Leymus chinensis+Stipa krylovii (LSt)?Leymus chinensis+Stipa baicalensis (LSb)? Leymus chinensis+Stipa grandis (LS)?Leymus chinensis+Carex pediformsis (LV) as the object of study to survey the biomass, soil carbon density, soil nitrogen density, analyze the relationship between soil organic carbon content and volume weight of soil.The results show:1. Community vegetation living layer biomass of the total 18 kinds of coenotype is between 91.12g/m2 to 286.82g/m2; and community earth surface litter layer biomass is between 24.4g/m2 to 124.76g/m2; community vegetation underground biomass is between 282.6g/m2 to 1338.75g/m2; community biomass is between 409.4g/m2 to 1626.32g/m2.2. Community vegetation living layer carbon density of the total 18 kinds of coenotype is between 45.56g/m2 to 143.41g/m2; community earth surface litter layer carbon density is between 12.2g/m2 to 62.38g/m2; community vegetation underground carbon density is between 141.30g/m2 to 669.38g/m2; soil carbon density is between 6778g/m2 to 15550g/m2. Soil nitrogen density and soil organic carbon density are decrease with the increase of soil depth, and mainly collected in the surface layer.3. Total carbon density of 18 kinds of coenotype is between 7119.78g/m2 to 16200.34g/m2, in every group distribution,soil organic carbon density occupies the highest proportion is between 94.64% and 98.21%.the total carbon density is relate to every part of carbon density,and shows highly significant positive correlation with soil organic density. Total carbon density shows significantly positive correlation with soil organic carbon density.