[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.