无牧草原生态系统营养元素的生物地球化学特征

以内蒙古锡林河流域的两种优势草原群落羊草草原和大针茅草原为研究对象，探讨了中纬度地区未放牧情况下的草原生态系统植物营养元素的生物地球化学特征．结果表明，两类草原群落土壤-植物系统中土壤分室N、P、K、S、Ca、Mg、Si的贮量远大于植物亚系统的贮量，地上活体和枯草分室的各元素贮量小于根分室．在两类草原群落中，N、P、K、S从枯草分室中消失的速率要大于Ca、Mg和Si．羊草草原的枯草分室元素流失量大于大针茅草原．研究区草原生态系统中，羊革草原物质的生物地球化学循环近于平衡状态，大针茅草原处于失衡状态．物质循环量羊草草原远大于大针茅草原．

Biogeochemical characteristics of nutrient elements in ungrazed grassland ecosystem in Xilin River Basin

The biogeochemical characteristics of nutrient elements in Leymus chinensis community and Stipa grandis community, which were both scarcely disturbed by human activities, in Xilin River Basin, Inner Mongolia were studied. The results showed that the storage of N, P, K, S, Ca, Mg, and Si in the soil compartment of soil plant system was higher than that in the plant subsystem of two communities,and their storage in the live shoots compartment was lower than that in the litter compartment. The disappearing rate of N, P, K and S from the litter compartment was higher than that of Ca, Mg, and Si in the two grassland communities.The decomposition rate of litter in Leymus chinensis community was higher than that in Stipa grandis community. In the grassland soil plant system,the matter flowing mass kept balance in Leymus chinensis community, but lost balance in Stipa grandis community. The matter participating in biogeochemical cycling in Leymus chinensis community was more than that in Stipa grandis community.