Stock and allocation of carbon and nitrogen in typical Ulmus pumila dominated savanna in Inner Mongolia, China
Zhao Yunjie, Tian Yun, Wang Xiao
College of Soil and Water Conservation, Beijing Forestry University, Key Lab. of Soil and Water Conservation and Desertification Combating, Ministry of Education, 100083, Beijing,China
Abstract：Ulmus pumila is widely distributed on the fixed sand dune in Horqin and Hunshandake sandy lands, Inner Mongolia. U. pumila-dominated savanna is the climax community of vegetation succession in these regions. Taking the typical U. pumila-dominated savanna (“ the savanna”hereinafter) in Horqin sandy land after the “grain for green”project and Hunshandake sandy land without disturbance as the research objects, the present study compared the stock and allocation patterns of carbon (C) and nitrogen (N) of the savanna in the two sandy lands by plot-level inventories, biomass estimation and the mathematical statistic methods. The results show that: 1) Except soil inorganic C stock, the C and N stocks in the total ecosystem and its different components in the savanna of Hunshandake sandy land were all significantly higher than those of the corresponding components in the same type of savanna of Horqin sandy land. The total ecosystem C and N stocks in the savanna of Hunshandake sandy land were 1.97 times and 1.82 times, respectively, as much as that of Horqin sandy land. 2) The C and N allocation patterns of the two savannas were similar. The soil was the largest contributor to the total ecosystem C and N stocks, and the corresponding portions were more than 55% and 80%, respectively, in both savannas. On the contrary, the forest floor contributed little to the total ecosystem C and N stocks in both savannas. 3) Compared with the savanna of Hunshandake sandy land, that of Horqin sandy land may have greater carbon and nitrogen sequestration potential.
2014, Vol. 12 
