斯洛文尼亚岩溶区草地昼夜尺度土壤CO_(2)含量与土温滞后效应  

Diurnal hysteresis between soil CO_(2) and soil temperature in karst grassland in Sloveni

作　　者：章程[1] 肖琼[1] 汪进良[1] 苗迎[1] Mitja PRELOVSEK 孙平安[1] 郭永丽 Martin KNEZ ZHANG Cheng;XIAO Qiong;WANG Jinliang;MIAO Ying;Mitja PRELOVSEK;SUN Ping'an;GUO Yongli;Martin KNEZ(Karst Dynamics Key Laboratory of Ministry of Natural Resources/Guangxi Zhuang Autonomous Region,Institute of Karst Geology,Chinese Academy of Geological Sciences and International Research Center on Karst Under the Auspices of UNESCO,Guilin 541004,Guangxi;Karst Research Institute,Slovenian Academy of Sciences and Arts,Postonja SI-6230,Slovenia)

机构地区：[1]中国地质科学院岩溶地质研究所/联合国教科文组织国际岩溶研究中心,自然资源部/广西岩溶动力学重点实验,广西桂林541004 [2]斯洛文尼亚科学与艺术院岩溶研究所,波斯托尼亚SI-6230

出　　处：《第四纪研究》2023年第2期381-389,共9页Quaternary Sciences

基　　金：国家重点研发计划项目(批准号:2020YFE0204700);科技部常规性科技援外项目(批准号:KY201802009);广西壮族自治区重点基金项目(批准号:2018JJD150024);桂林市科学研究与技术开发研究项目(批准号:20180107-1)共同资助。

摘　　要：土壤CO_(2)含量及其变化规律研究,关系到土壤呼吸CO_(2)排放通量估算的准确性,昼夜尺度土壤CO_(2)与土温滞后效应形成机理与影响因素是其核心研究内容。本研究以斯洛文尼亚典型岩溶区草地土壤系统为例,开展土壤CO_(2)、土温与土壤水分高分辨率监测,分析昼夜尺度土壤CO_(2)与土温滞后效应及其产生原因,讨论滞后程度的多日演变规律及其与土壤水分的关系。结果表明,生长季土壤CO_(2)含量、土壤温度和土壤水分变化分别为1986~6689 ppm、14.69~23.55℃和16.4%~33.3%,均值分别为3578 ppm、19.69℃和23.3%。土壤温度和土壤CO_(2)均呈现出白天上升夜间下降的昼夜变化特征,后者昼夜变幅为176~780 ppm,均值425 ppm。土壤CO_(2)与土温昼夜滞后环呈顺时针方向演变,土壤干化阶段滞后环呈螺旋式下降,降雨期间则表现为螺旋式上升。滞后环的出现主要受光合有效辐射和土壤温度控制,也与土壤微生物种类密切相关,滞后程度受土壤水分含量控制,水分越高滞后效应越显著,水分大于25%时,滞后环宽度值高达300~800 ppm;低水分时滞后效应减弱,此时土壤CO_(2)与土温接近于线性相关。降雨期间土壤CO_(2)有快速下降现象,暗示部分CO_(2)随雨水脉冲过程向下运移,成为下伏碳酸盐岩溶蚀驱动力,为准确估算岩溶区土壤呼吸排放通量和评价岩溶作用的土壤CO_(2)减源效应提供了科学依据。The study of soil CO_(2) concentration and its variation is pivotal to the accuracy of soil respiration CO_(2) efflux estimation,in which the formation mechanism and influencing factors of diurnal hysteresis between soil CO_(2) and soil temperature are two key aspects.In this paper,high-resolution monitoring of soil CO_(2),soil temperature and soil moisture at the depth of 20cm in a typical karst grassland(45°45'37″N,14°28'14″E)in Postojna,Slovenia was conducted,the hysteresis effect of soil CO_(2) and soil temperature at the diurnal scale and its causes were analyzed,and the multi-day evolution of hysteresis magnitude and its relationship with soil moisture was discussed as well.The monitoring work was deployed in growing season form June 1 to September 30 of year 2021 with 30min interval resolution.The results showed that soil CO_(2) concentration,soil temperature and soil moisture changed in the range of 1986~6689 ppm,14.69~23.55℃and 16.4%~33.3%respectively during the monitoring period,with mean values of 3578 ppm,19.69℃and 23.3%respectively.Both soil temperature and soil CO_(2) showed diurnal variation characteristics of increasing during the day and decreasing at night,the diurnal range of the latter is 176~780 ppm with an average of 425 ppm.During the period of no rain,soil CO_(2) changed with soil moisture,and there was a significant linear correlation between them.The diurnal hysteresis loop direction changed clockwise.The hysteresis loop evolved as a downward spiral during soil drying period and as an upward spiral during rainfall events.The hysteresis effects are mainly controlled by photosynthetic active radiation and soil temperature,and also closely related to soil microbial species.The hysteresis magnitude(HM)is controlled by soil moisture content,that is,the higher the moisture content is,the more significant the hysteresis effect is,HM values reached as high as 300~800 ppm while soil moistures were larger than 25%.The hysteresis effect is weakened at low water content,and soil CO_(2) ten

关 键 词：土壤CO_(2) 土温 滞后效应 土壤水分 岩溶草地 斯洛文尼亚 

分 类 号：P595[天文地球—地球化学]