京津风沙源治理工程对草地土壤有机碳库的影响——以内蒙古锡林郭勒盟为例

研究草地生态建设工程对土壤有机碳库的影响，对于草地生态建设工程成效评估及草地碳循环研究具有重要意义.本文以内蒙古锡林郭勒盟京津风沙源治理工程区为例，采用IPCC推荐的碳收支清单法，分析了2000-2006年京津风沙源治理工程对草地土壤有机碳库的影响，并对3种管理措施下（人工种草、飞播牧草和围栏封育）草地土壤达到最大有机碳密度的时间进行估算.结果表明： 2000-2006年，京津风沙源治理工程对草地土壤碳汇具有极大的促进作用，工程区整体表现为碳汇，碳汇量为59.26×10⁴ t C；不同草地管理方式下草地土壤固碳速率和效益差异显著，其中，人工种草的土壤固碳速率较快，为0.25 t C·hm^-2·a^-1，而围栏封育导致土壤固碳效益较高（0.63亿元）；与其他草地类型相比，低地草甸和温性草甸草原的土壤固碳速率较快，均为0.14 t C·hm^-2·a^-1.通过管理措施使草地达到潜在最大土壤有机碳密度是一个长期的过程，相对而言，人工种草所需的时间较短（57.75年）.

Impact of the Beijing and Tianjin Sand Source Control Project on the grassland soil organic carbon storage: A case study of Xilingol League,Inner Mongolia,China.

Understanding the impacts of eco construction project on grassland soil carbon storage is crucial to assess the effectiveness of the project and its role in carbon cycling of the grassland ecosystems. Using IPCC carbon budget inventory method, this paper analyzed the influence of Beijing and Tianjin Sand Source Control Project (BTSSCP) on the grassland soil carbon storage between 2000 and 2006 in Xilingol League, Inner Mongolia, and evaluated the time needed to reach the maximal soil carbon density for three management practices (i.e., sown pasture, aerial sowing pasture, and grazing exclosure). Results showed that the BTSSCP significantly increased soil carbon storage, with a carbon sequestration of 59.26×10⁴ t C from 2000 to 2006. The rate and effectiveness of soil carbon sequestration varied significantly with management practices, with the highest rate in sown pasture (0.25 t C·hm^-2·a^-1) while a greater benefit of soil carbon sequestration in the grazing exclosure (63 million yuan). Compared with other grassland vegetations, lowland meadow and temperate meadow steppe both had higher carbon sequestration rates of 0.14 t C·hm^-2·a^-1. Long time would be needed to reach the maximum soil carbon density in grassland under the three practices, yet shorter for sown pasture with average of 57.75 years.