锡林河流域一个原生草原群落的碳素平衡研究

野外调查与历史资料相结合,对内蒙古锡林河流域一个永久试验样地内的羊草( Leymus chinensis (Trin.) Tzvel.)草原群落(原生草原群落)的碳素贮量、主要流量和周转速度等进行了估计.结果表明:1)该群落中地上部净初级生产的碳素固定量的多年平均值为79.8 g C*m-2*a-1,根系碳素输入量的多年平均值为311.9 g C*m-2*a-1,碳素输入总量为391.7 g C*m-2*a-1; 2)土壤净呼吸量为346.9 g C*m-2*a-1,动物(昆虫)采食量14.7 g C*m-2*a-1,地上立枯阶段的淋溶与光化学分解损失为3.2 g C*m-2*a-1,碳素输出总量为364.8 g C*m-2*a-1; 3)该群落中碳素输入略大于输出,净积累速率为26.9 g C*m-2*a-1,0-30 cm土壤中的碳素周转速率为6.2%,周转时间为16年.

Soil Carbon Balance in a Native Temperate Grassland in the Xilin RiverBasin of Inner Mongolia

Based on historical data and field investigation, some major fluxes and reserves of carbon were estimated, and a tentative analysis of the soil carbon balance was made in a native grassland community in the Xilin River basin of Inner Mongolia. Major results were reported as follows: 1) Annual average carbon input from above ground biomass production was 79.8 g C·m-2·a-1, and from root biomass to 30 cm depth averaged 311.9 g C·m-2·a-1. The summed mean annual carbon input of shoot and root materials in the study site was approximately 391.7 g C·m-2·a-1. 2) The annual amount of above ground biomass consumed by insects averaged 14.7 g C·m-2·a-1, and the carbon output by leaching or light chemical oxidation was 3.2 g C·m-2·a-1. The annual evolution rate of CO2 from net soil respiration averaged 346.9 g C·m-2·a-1, and the summed mean annual output was approximately 364.8 g C·m-2·a-1. 3) A mature, steady state system could be assumed for the community for which growth and decay were approximately in balance, with a net carbon accumulation of about 26.9 g C·m-2·a-1. Based on the soil organic carbon density of the field, the turnover rate of soil carbon in 0-30 cm depth was calculated to be 6.2%, with a turnover time of 16 years.