内蒙古锡林郭勒盟典型草原固碳量及固碳潜力估算

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

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。

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.