内蒙古锡林郭勒盟典型草原固碳量及固碳潜力估算

为了评价不同放牧强度对草原固碳量及固碳潜力的影响，本研究采用系统动力学建模方法耦合CASA光合利用率模型、Shiyomi放牧模型、Raich土壤呼吸模型等模型，建立了基于系统动力学库-流思路的碳循环模型，该模型包含3个子系统、4个碳库。结果表明：1998至2015年，在内蒙古锡林郭勒盟的温度降低、降水量增加的背景下，净初级生产力呈现升高的趋势，典型草原土壤固碳量呈现下降趋势；放牧强度在3羊·公顷^-1下净生态系统初级生产力最低，固碳潜力最大，分别为-16.2 gC·m^-2和24.84 TgC。因此，建议内蒙古锡林郭勒盟典型草原西部（阿巴嘎旗、那仁宝力格站）的放牧强度不宜超过1.5羊·公顷^-1；东部（多伦县、东乌珠穆沁、西乌珠穆沁、锡林浩特站）不宜超过4.5羊·公顷^-1。

The Estimation of Actual and Potential Carbon Sequestration in Typical Steppe in Xilingol County,Inner Mongolia

In order to assess the influence of grazing intensity to grassland actual and potential carbon sequestration, this study coupled pool-flux model with CASA light-efficiency model, Shiyomi grazing model, Raich soil respiration model, etc., establishing the annual sample-scaled coupled human and natural carbon cycle model within the systematic dynamic modeling framework, which involved three sub-systems and four carbon pools. Results showed that under the background of ‘cooling and wetting’ trends in Xilingol County, Inner Mongolia, the NPP showed a trend of increasing;and the annual NEP of typical grassland showed a trend of decreasing. The productivity was the lowest and potential carbon sequestration was the highest under the grazing intensity of 3 sheep·ha^-1, which was -16.2 gC·m^-2 and 24.84TgC, respectively. Thus we suggested that the grazing intensity in the western typical grassland of Xilin Gol (Nambaolige station, League) in Inner Mongolia should not exceed 1.5 sheep·ha^-1, and the grazing intensity in the eastern typical grassland (Duolun County, East Ujumchin, West Ujumchin, Xilinhot) should not exceed 4.5 sheep·ha^-1.