长期封育对不同类型草地碳贮量及其固持速率的影响

长期封育对不同类型草地碳贮量及其固持速率的影响内容摘要：

生 态 学 报 ACTA ECOLOGICA SINICA 第 31 卷第 15 期 2011 年 8 月 Vol． 31，No． 15 Aug． ， 2011 2011， 31（ 15） ： 4270-4276． 何念鹏，韩兴国，于贵瑞． 长期封育对不同类型草地碳贮量及其固持速率的影响． 生态学报， He N P，Han X G，Yu G R． Carbon and nitrogen sequestration rate in long-term fenced grasslands in Inner Mongolia，China． Acta Ecologica Sinica， 2011， 31（ 15） ： 4270-4276． 长期封育对不同类型草地碳贮量及其固持速率的影响 何念鹏 1， 2，* ，韩兴国2 ，于贵瑞1 （ 1． 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 2． 中国科学院植物研究所，植被与环境变化国家重点实验室，北京 100093） 摘要：基于 4 个长期封育草地，采用成对取样方法（ 封育-自由放牧草地） 分析了长期封育和自由放牧草地地上生物量、地表凋落 0—100 cm 根系和土壤的碳氮贮量，探讨了长期封育草地的碳固持速率。实验结果表明： 长期封育显著提高了草地碳氮贮 物、 －2 －2 －2 －1 量； 经 30a 围封处理后，草地碳固持量为 1401—2858 g C m ，平均 2126 g C m ； 草地碳固持速率为 46. 7—129． 2 g C m a ， －2 －1 －2 －1 －2 －1 平均 84． 2 g C m a 。长期封育草地氮固持速率为 2． 8—14． 7 g N m a ，平均 7． 3 g N m a 。封育草地碳和氮固持速率 表现为： 针茅草地 ＜ 羊草草地 ＜ 退化羊草草地 ＜ 补播黄花苜蓿 + 羊草草地。长期封育草地 0—40 cm 土壤碳固持速率相对较 高，但下层土壤对草地碳固持的贡献也比较大，因此，未来的相关研究应给予下层土壤更大关注。内蒙古典型草地具有巨大的 碳固持潜力，长期封育（ 或禁牧） 是实现其碳固持效应最经济、最有效的途径之一。 关键词：草地； 碳固持； 氮贮存； 固持速率； 土地利用变化； 围封 Carbon and nitrogen sequestration rate in long-term fenced grasslands in Inner Mongolia，China HE Nianpeng 1， 2，* ，HAN Xingguo2 ，YU Guirui1 1 Key Laboratory of Ecosystem Network Observation and Modeling，Institute of Geographic Sciences and Natural Resources Research，CAS，Beijing 100101，China 2 Key Laboratory of Vegetation and Environmental Change，Institute of Botany，CAS，Beijing 100093，China Abstract： Land-use change is considered to have a significant impact on the global C balance by profoundly altering biota， land cover，and biogeochemical cycles． Therefore，the impact of land-use change on the storage or sequestration of carbon （ C） and nitrogen （ N） is one of the most important domains to global change research． As a dominant form of landscape and an integral component of the Eurasian landmass，grasslands of northern China，which account for 40% of the land area in China，play important roles in servicing the ecological environment and in the socio-economy of the region． Furthermore， an increase in the soil C and N storage in the grasslands of northern China is anticipated with the implementation of measures aimed at encouraging grassland protection． However，there is little information regarding the potential of C and N storage （ or C sequestration rate） due to the absence of long-term grazing exclusion plots in multiple sites． In this present research，using pair-sampling methods，we investigated the C and N storage in aboveground biomass， litter，roots and soil organic matter in the 0 100 cm soil layer in the fenced grasslands and free-grazing grasslands in 4 sites． The main objectives of this study was to assess the effect of long-term grazing exclusion on the storage of C and N in temperate grasslands of northern China，and further determined the sequestration rates of C and N in fenced grasslands by comparing with the data of free grazing grasslands． The results showed that，compared with free-grazing grasslands，there were significant increases in the C and N storage 基金项目：国家基础研究发展计划项目（ 2010CB833504） ； 国家自然科学基金资助项目（ 31070431，40803024） 收稿日期：2011-03-02； 修订日期：2011-05-09 * 通讯作者 Corresponding author． E-mail： E-mail： henp@ igsnrr． ac． cn http： / / www． ecologica． cn 15 期 何念鹏 等： 长期封育对不同类型草地碳贮量及其固持速率的影响 4271 in the fenced grasslands． It was estimated that，after 3-decades grazing exclusion，the quantity of C sequestration ranged from 1401 to 2858 g C m –2 in the 4 sites，averaging 2126 g C m － 2 ； and the rates of C sequestration in fenced grasslands ranged from 46． 7 to 129． 2 g C m － 2 a － 1 ，averaging 84． 2 g C m － 2 a － 1 ． The rates of N sequestration in fenced grasslands varied from 2． 8 to 14． 7 g N m － 2 a － 1 ，averaging 7． 3 g N m － 2 a － 1 ． From the view of C and N sequestration rates，there is a total trend as follows： Stipa grandis grassland ＜ Leymus chinensis grassland ＜ degraded L． Chinese grassland ＜ Sowing Medicago falcata and L． chinensis grassland． Moreover，we found that the lower soil layers （ 40 100 cm） had also play an important role in the total C and N sequestered in fenced grasslands although sequestration rates were relative higher in the upper soil layer （ 0 40 cm） ． Together，the study demonstrated that temperate grasslands of northern China have the vast potential to increase C storage，and long-term grazing exclusion should be the most valuable and feasible approach to make true the C sequestration of temperate grasslands in future． Key Words： grassland； carbon sequestration； nitrogen storage； sequestration rates； land-