青藏高原高寒草地土壤碳矿化及其温度敏感性  

Soil C mineralization and temperature sensitivity in alpine grasslands of the Qinghai-Xizang Plateau

作　　者：徐丽[1,2] 于书霞 何念鹏[2] 温学发[2] 石培礼[2] 张扬建[2] 代景忠[3] 王若梦[2] 

机构地区：[1]华中农业大学资源与环境学院,武汉430070 [2]中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室,北京100101 [3]内蒙古农业大学生态环境学院,呼和浩特010019

出　　处：《植物生态学报》2013年第11期988-997,共10页Chinese Journal of Plant Ecology

基　　金：国家科技支撑计划(2012BAC01B08);国家自然科学基金(31270519)

摘　　要：青藏高原具有独特的海拔、气候和生态系统类型,弄清其土壤有机质分解及其温度敏感性对于揭示青藏高原土壤碳储量变化及其碳汇功能具有重要意义。该文利用青藏高原西北部草地的11个封育-自由放牧成对草地,通过测定不同温度(5、10、15、20和25℃)培养下的土壤碳矿化速率,探讨了土地利用方式对该地区土壤碳矿化及其温度敏感性的影响。实验结果表明:温度对青藏高原高寒草地的土壤碳矿化具有显著影响,温度越高土壤碳矿化量越大。从东至西,土壤碳矿化量逐渐降低。草地土壤碳矿化量与土壤有机碳和土壤全氮含量显著正相关;即土壤有机碳和土壤全氮含量越高,土壤碳矿化量就越高。土地利用方式对土壤碳矿化的温度敏感性(Q10)无显著影响,Q10值变化范围为1.4–2.4;其中,放牧草地Q10的平均值为1.83,封育草地Q10的平均值为1.86。此外,Q10与土壤有机碳和土壤全氮含量无显著的相关关系,也无明显的空间格局。放牧和封育对青藏高原高寒草地土壤碳矿化的温度敏感性无显著影响,为深入分析青藏高原土壤碳汇功能及其对未来气温升高的响应提供了重要的理论依据。Aims Currently, the temperature sensitivity of soil carbon （C） mineralization and the factors that control it are the focus of studies on soil C cycle and global climate change. The main objectives of this study were to： （1） in- vestigate the effects of temperature and land-use （fenced grassland vs. grazing grassland） on soil C mineralization and its temperature sensitivity （Ql0） in the grasslands of Qinghai-Xizang Plateau and （2） determine the relation- ships of the rate of soil C mineralization with soil properties （e.g. soil organic carbon content （SOC）, soil total ni- trogen content （STN））. Methods Eleven pairs of plots （fenced sites vs. grazing sites） were selected along an east-west transect in northwest of Qinghai-Xizang Plateau. Soil samples were collected at a depth of 0-20 cm, to measure soil C min- eralization rates under a temperature gradient （i.e. 5, 10, 15, 20, and 25 ~C） in laboratory. Data for soil C miner- alization rate on the 7th day and 56th day, respectively, were used to assess the short- and long-term effects. lmportantfindings Soil C mineralization rates declined from east to west on fenced sites, but varied slightly on the grazing sites. Soil C mineralization rates increased significantly with increasing incubation temperature, and were strongly related to SOC and STN,＂ higher the SOC and STN, greater the accumulative soil C mineralization. Pl0 showed no apparent spatial pattern along the east-west transect, and was not susceptible to land-use with av- erage Q10 values of 1.83 and 1.86 on the fenced sites and the grazing sites, respectively. Moreover, Q^0 was not correlated with either SOC or STN. Findings in this study provide new insights on the responses of soil C miner- alization and its temperature sensitivity to land-use change on the Qinghai-Xizang Plateau, contributing important information for evaluating soil C sequestration and its response to wanning scenarios in this region.

关 键 词：土地利用方式 Q10 青藏高原 土壤有机质 空间格局 温度敏感性 

分 类 号：S812[农业科学—草业科学]