西南喀斯特地区灌丛林土壤CO2、CH4通量研究  

CO_2 and CH_4 fluxes from soil of scrub forest in the karst area of southwest China

作　　者：房彬[1,2] 李心清[1] 张立科[1,2] 程建中[1] 王兵[1] 程红光[1] 杨放[1,2] 

机构地区：[1]中国科学院地球化学研究所环境地球化学国家重点实验室,贵州贵阳550002 [2]中国科学院大学北京100049

出　　处：《地球化学》2013年第3期221-228,共8页Geochimica

基　　金：国家自然科学基金(40872212);中国科学院战略性科技先导专项(碳专项);贵州省农业攻关计划项目(黔科合NY字[2011]3079号)

摘　　要：灌丛林生态系统是西南喀斯特地区广泛分布的生态系统类型,在区域生态系统碳循环和碳平衡中有重要作用。为估算亚热带喀斯特地区CO2和CH4源汇现状,评价灌丛林生态系统对温室效应的影响,以贵阳市开阳县灌丛林为研究对象,采用静态箱-气相色谱法观测CO2和CH4通量的季节变化。对2010年12月到2012年1月的观测结果分析表明,灌丛林地土壤表现为CO2的释放源和CH4的吸收汇,CO2通量的变化范围为33.20～1106.75 mg/(m2.h),年平均通量为342.98 mg/(m2.h);CH4通量的变化范围为–206.14～–59.85μg/(m2.h),年平均通量为–103.22μg/(m2.h)。CO2排放通量和CH4吸收通量均表现出明显的季节变化规律,两者最高值均出现在夏季,不同的是CO2排放通量最低值出现在12月,而CH4吸收通量最高值则出现在11月。土壤温度和土壤湿度是影响灌丛林土壤CO2通量的主要因子,双因素模型(F=αeβTWγ)较好拟合了土壤温度和土壤湿度对土壤呼吸的影响,两者共同解释了CO2通量变化的81.4%。土壤CH4吸收通量与温度存在显著正相关关系,其中5 cm土壤温度同CH4吸收通量相关性最好,但温度超过一定阈值时,两者相关性降低。土壤CH4吸收通量与土壤湿度呈显著负相关关系表明,水分是土壤氧化CH4的重要限制因子。Shrub forest is an important, widely distributed ecosystem type in karst area of southwest China, playing an important role in the regional carbon cycle and balance. Our objectives were to evaluate the CO2, CH4 budgets of karst area of southwest China, and estimate the influence of shrub forest ecosystem on greenhouse effects. Taking shrub forest in Kaiyang country of Guizhou province as our study object, we used static enclosed chamber coupled with GC to observe the seasonal changes in soil CO2, CH4 fluxes. The results showed that the forest soil performed as a source for CO2 and a sink for CH4 to the atmosphere; annual CO2 flux ranged from 33.20 to 1106.75 mg/（m^2·h） with an average of 342.98 mg/（m^2· h）, and annual CH4 flux ranged from -206.14 to -59.85 μg/（m^2· h） with an average of -103.22μg/（m^2·h）. There are significant seasonal variations in both CO2 emission flux and CH4 absorption flux： their maximums both appeared in summer, while minimum CO2 emission flux occurred in December and minimum CH4 absorption flux in November. Soil temperatures and soil moistures were the two main factors regulating the soil CO2 flux of shrub forest. The relationship of soil respiration rate （F） with soil temperature （T） and soil moisture （W） fit well with the equation F =α e^βT W^γ （α, β, γ were constants）. The results showed that soil temperatures and soil moistures together accounted for 8l .4% of the seasonal variations in soil respiration rate. Soil CH4 absorption flux increased along with the temperature, and had the highest correlation with soil temperature at the depth of 5 cm. Besides, the correlation between soil CH4 absorption flux and soil temperature decreased as temperature increased. Significant negative correlation between CH4 absorption flux and soil moisture indicated that soil moisture was one important factor that limits soil CH4 oxidation.

关 键 词：土壤 CO2通量 H4通量 温度 湿度 喀斯特地区 

分 类 号：P588.121[天文地球—岩石学]