中文摘要：

选取内蒙古典型草原不同围封年限（0,8,11,14,21,25年）土壤为研究对象,采用室内培养的方法,调节含水量至25%（W/W）,并注入纯CH4（使瓶内初始CH4浓度分别为2.24,340,7000μL.L-1）后密封,在（25±1）℃条件下恒温培养,研究不同围封年限土壤对CH4吸收能力的影响。结果表明：与自由放牧草地相比,重度退化草地采取生长季围封恢复措施后,围封年限对CH4吸收有显著影响（F=11.1134,P〈0.01）,草地围封8年时土壤吸收CH4的能力达到最大,而在14年时吸收能力最小。针对不同初始外源CH4浓度而言,CH4的累积吸收量随CH4初始浓度的升高而升高,在低、中初始CH4浓度下CH4的累积吸收量与土壤有机碳含量成负相关（R=0.9292,P〈0.01;R=0.7502,P〈0.05）,表明土壤有机碳和外源CH4浓度是影响土壤CH4吸收的重要因子。

英文摘要：

A typical steppe was selected in the Inner Mongolia as the research object.Using a laboratory incubation method,50 g dried soil sample was put in 300 mL flask,adjusting content to 25%（W/W） with water.The flasks were sealed after injecting pure CH4（CH4 initial concentration in the bottle are respectively 2.24,340 and 7000 μL·L-1） and cultured at（25±1）℃.The changes of CH4 uptake in different fencing years（0,8,11,14,21 and 25 years） were studied.Results showed that appropriate fencing duration increased the capacity of CH4 uptake compared with free grazed grassland.Fenced years significantly influence the CH4 absorption of soil（F=11.1134,P0.01）.The capacity of CH4 absorption reached the maximum after fenced for 8 years and reached the minimum after fenced for 14 years.Cumulative CH4 uptake increased with soil organic carbon decreasing and initial CH4 concentration increasing.Cumulative CH4 uptake and soil organic carbon content was negatively correlated at the initial CH4 concentration of 2.24 and 340 μL·L-1（R=0.9292,P0.01;R=0.7502,P0.05）.It indicated that the main influencing factors of CH4 uptake were soil organic carbon and CH4 concentration.