山西暖性草地碳密度分布特征及其区域差异

山西省草地是我国草地碳储量精确估测中不可忽视的部分。为探究山西省暖性草地生态系统碳密度的区域差异，本研究调查和测定了该省2个气候区（晋东南半湿润区，晋西北半干旱区）暖性草地群落特征和生态系统碳密度。结果表明：不同气候区的环境差异影响了草地植物物种多样性、生物量积累和土壤碳输入，造成2个气候区碳密度分异的主要环境因子为降水量和土壤有机碳含量；晋西北平均植物多样性指数略高于晋东南；晋西北和晋东南平均地上生物量分别为384.28 g·m^-2，522.83 g·m^-2，平均地下生物量分别为1 411.02 g·m^-2，1 643.81 g·m^-2，晋西北均低于晋东南；平均生态系统碳密度分别为7 911.48 g·m^-2，9 080.43 g·m^-2；其中植被地上部分、根系和土壤碳密度占比分别为1.4%~2.1%，12.3%~24.7%，73.6%~85.9%；晋东南地区暖性灌草丛类草地生态系统碳密度最大，为10 102.23 g·m^-2。

Distribution Characteristics of Carbon Density in Warm-temperate Grassland and its Regional Difference in Shanxi

Grassland in Shanxi Province is an important part in the accurate estimation of grassland carbon reserves in China. By investigating and measuring the community characteristics and carbon density of warm-temperate grassland in two climatic regions of Shanxi (including the semi-arid area in northwest Shanxi and the semi-humid area in southeast Shanxi),the regional differences of ecosystem carbon density of warm-temperate grassland in Shanxi were analyzed. The results showed that the environmental differences in different climatic regions affected the diversity of grassland plants,biomass accumulation and soil carbon input,and the main environmental factors causing the difference of carbon density in the two climatic regions were precipitation and soil organic carbon content. The average plant diversity index of northwest Shanxi was slightly higher than that in southeast Shanxi. The average aboveground biomass of northwest and southeast regions were 384.28 g·m^-2 and 522.83 g·m^-2,respectively,and the average belowground biomass were 1 411.02 g·m^-2 and 1643.81 g·m^-2,respectively,both of which were lower in the region of northwest than that in southeast Shanxi. The average carbon densities of ecosystems were 7 911.48 g·m^-2 and 9 080.43 g·m^-2 in northwest and southeast regions,respectively. The proportions of vegetation,root system and soil carbon density were 1.4%~2.1%,12.3%~24.7% and 73.6%~85.9%,respectively. The carbon density of the warm temperate shrub-tussock ecosystem in southeast Shanxi was the highest,at 10 102.23 g·m^-2.