喀斯特地区土壤CO_2扩散通量变化特征及其影响因素分析  

The Variation Characteristics of Soil CO_2 Diffusion Flux and the Influencing Factors Analysis in Karst Area

作　　者：殷超[1,2] 周忠发[1,2] 张绍云[1,3] 汪炎林 张结[1,2] 田衷珲 YIN Chao;ZHOU Zhongfa;ZHANG Shaoyun;WANG Yanlin;ZHANG Jie;TIAN Zhonghui(School of Karst Science, Guizhou Normal University, Guiyang 550001, China;The State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province, Guiyang 550001, China;State Engineering Technology Institute for Karst Desertification Control, Guiyang 550001, China)

机构地区：[1]贵州师范大学//喀斯特研究院,贵州贵阳550001 [2]贵州省喀斯特山地生态环境国家重点实验室培育基地,贵州贵阳550001 [3]国家喀斯特石漠化防治工程技术研究中心,贵州贵阳550001

出　　处：《生态环境学报》2017年第7期1122-1130,共9页Ecology and Environmental Sciences

基　　金：国家自然科学基金地区项目(41361081);贵州省高层次创新型人才培养计划--"百"层次人才(黔科合平台人才[2016]5674);贵州省重大应用基础研究项目(黔科合JZ字[2014]200201)

摘　　要：土壤CO_2通量是全球碳循环的重要组成部分,研究土壤垂直剖面CO_2通量的分布是了解生态系统碳循环的重要途径。因此,对喀斯特地区土壤剖面CO_2扩散通量(F值)进行研究,有助于了解喀斯特地区碳循环过程。自2016年1月—2016年12月,对大风洞上覆土壤CO_2浓度、土壤温度等指标进行长期监测并采集土壤样品,利用环刀法对土壤孔隙度和自然含水率等指标进行测定。结合土壤CO_2浓度、土壤温度、土壤孔隙度和土壤含水率等指标,运用Fick定律对不同土层深度F值进行计算,并利用多元回归模型将各因子对F值的影响程度进行量化,从而探讨各个深度土壤CO_2扩散通量大小和各因子对F值的贡献率。结果表明:土壤CO_2浓度具有显著的季节变化特征,冬夏两季的差值范围可达0.245~0.817μmol·mol^(-1)。各土壤监测点的土壤孔隙度(包括总孔隙度和充气孔隙度)具有显著的浅层大于深层的垂直分布规律,浅层土壤总孔隙度和充气孔隙度可分别达61.85%和55.47%,而深层最高仅为49.07%和40.96%。土壤体积含水率和土壤容重在表层土壤的波动性较大,随着深度增加,波动性不断减弱。表层土壤的F值高于深层土壤,20 cm深度F均值可达0.39μmol·m^2·s^(-1),而80 cm深度F均值仅为0.23μmol·m^2·s^(-1)。对F值影响最大的因素包括运移距离、土壤充气孔隙度、土壤CO_2浓度,其贡献率均值分别可达32.49%,26.69%,18.74%;而土壤总孔隙度和土壤体积含水率,贡献率均值分别为6.76%和6.31%;土壤温度和土壤容重的贡献率较弱。Soil CO2flux is an important component of the global carbon cycle.Studying the CO2flux distribution of soil profile is animportant way to understand the carbon cycle of ecosystem.Therefore,the study of CO2diffusion flux(F value)of soil profile inKarst area is helpful to understand the process of carbon cycle in Karst area,and it has great significance to the ecologicalenvironment protection in Karst area.Since January2016-December2016,the soil CO2concentration,soil temperature and otherindicators of Dafeng Cave overlying soil were monitored chronically and the soil samples were collected.At the same time,the soilporosity and natural water content index were determined and computed by ring-knife method.Combined with soil CO2concentration,soil temperature,soil porosity,soil water content and other index,the Fick diffusion law was used to calculate soilCO2diffusion flux in different depths of soil.The main factors affecting the diffusion flux were analyzed by using multipleregression models,and the influence degree of each factor on the diffusion flux was quantified.The result showed that there was asignificant seasonal variation of soil CO2concentration,the difference range between winter and summer of four soil monitoringpoints reached0.245~0.817μmol·mol-1.In terms of soil physical properties,the soil porosity(including total porosity and aeratedporosity)of each soil monitoring site had a significant perpendicular distribution pattern of shallow layer larger than deep layer.Thetotal porosity and aerated porosity of shallow soil had reached61.85%and55.47%respectively,while those in deep layer were only49.07%and40.96%.Soil bulk moisture content and soil bulk density fluctuated greatly in surface soil,and its fluctuation rangedecreased with the increase of depth.Affected by soil CO2concentration,transmission distance and soil porosity,the F value ofsurface soil was higher than that of deep soil,and the mean F value of20cm depth could reached0.39μmol·m2·s-1,while the mean Fvalue of80cm depth was only0.23μmol·m2

关 键 词：喀斯特 土壤CO2浓度 扩散通量 多元回归分析 贡献率 

分 类 号：S152.6[农业科学—土壤学] X144[农业科学—农业基础科学]