希拉穆仁荒漠草原围封区植物群落土壤有机碳研究OACSTPCD

The aims of this study are To clarify soil organic carbon content of each plant community and to provide a theoretical basis for grassland conservation.[Methods]Six plant communities(Stipa breviflora,Koeleria cristata,Leymus chinensis,Stipa krylovii,Convolvulus ammannii,Allium mongolicum)in the enclosed area of Xilamuren Desert Grassland were studied for soil mechanical composition,soil organic carbon con-tent and root characteristics of different plant communities.[Results](1)The soil mechanical composition of soil depth of 0-30 cm in six plant communities was mainly composed of silt and extremely fine sand,with the average values of 26.50％～54.62％and 16.90％～34.08％,respectively.(2)The root biomass of six plant communi-ties gradually decreased with soil depth,and the total root biomass was between 229.21 and 731.71 g/m2.Judging from characteristics of root distribution,the root distribution of Stipa brevifllora was'E'type distribution,and the root distributions other plant communities were6V'type distribution.(3)Soil organic carbon content of six plant communities gradually decreased with soil depth.The average organic carbon content in 0-30 cm ranged from 6.07 to 11.75 g/kg.(4)There was a significant positive correlation between root biomass,soil organic carbon and clay,and a significant positive correlation with silt,indicating that the more soil particles and clay content,the richer the root biomass and soil organic carbon of different plant communities.[Conclusion]Enclosure could effectively promote the increase of soil organic carbon,but organic carbon varied in response to different vegetation communities.The accuracy of grassland organic carbon storage should be determined according to the characteristics of grassland vegetation communities.