干旱对栓皮栎人工林碳水通量及其耦合的影响  

Impact of drought on carbon and water fluxes and their coupling in a Quercus variabilis plantation

作　　者：王音 同小娟[1] 张劲松[2,3] 李俊 孟平[2,3] 刘沛荣[1] 张静茹 WANG Yin;TONG Xiao-Juan;ZHANG Jin-Song;LI Jun;MENG Ping;LIU Pei-Rong;ZHANG Jing-Ru(School of Ecology and Nature Conservation,Beijing Forestry University,Beijing 100083,China;Research Institute of Forestry,Chinese Academy of Forestry,Beijing 100091,China;Henan Xiaolangdi Forest Ecosystem National Observation and Research Station,Jiyuan,Henan 454650,China;Key Laboratory of Water Cycle and Related Land Surface Processes,Institute of Geographical Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China)

机构地区：[1]北京林业大学生态与自然保护学院,北京100083 [2]中国林业科学研究院林业研究所,北京100091 [3]河南小浪底森林生态系统国家野外科学观测研究站,河南济源454650 [4]中国科学院地理科学与资源研究所陆地水循环及地表过程重点实验室,北京100101

出　　处：《植物生态学报》2024年第9期1157-1171,共15页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(32271875,31872703);国家重点研发计划(2020YFA0608101)

摘　　要：水分利用效率(WUE)是深入理解生态系统碳水循环以及耦合机制的重要指标。固有水分利用效率(IWUE)相较于WUE更适于分析日尺度上的生态系统碳水耦合机制。该研究利用涡度相关技术和微气象观测系统,对栓皮栎(Quercus variabilis)人工林生态系统的碳水通量及环境要素开展定位观测,分析了2021-2022年生物物理因子对该生态系统总初级生产力(GPP)、蒸散(ET)和IWUE的影响,明确了碳水通量及其耦合对干旱的响应机制。结果表明:GPP、ET和IWUE呈明显季节性变化。丰水年份GPP比正常年份高7.9%,ET比正常年份高21.0%,IWUE比正常年份低21.4%。空气水汽压亏缺(VPD)是影响正常年份GPP的主要因子,净辐射(R_(n))是限制丰水年份GPP的主要因子。不论是正常年份还是丰水年份,R_(n)均为ET的主要调控因子。相对土壤含水量(REW)是调控正常年份IWUE的主要因子,叶面积指数(LAI)是影响丰水年份IWUE的主要因子。环境因子通过调控冠层导度(g_(c))来调节碳水通量,进而影响IWUE。土壤干旱的发生会显著提高IWUE。GPP和ET对REW的响应滞后1个月,IWUE对REW的响应无时滞现象。Aims Water use efficiency(WUE)is an important indicator for understanding the carbon and water cycles and coupling mechanisms in terrestrial ecosystems.Inherent water use efficiency(IWUE)is a more suitable indicator than WUE for analyzing the carbon-water coupling mechanism of ecosystems on a daily scale.Here,we aimed to investigate the mechanism of water and carbon fluxes and their responses to drought in a planted forest ecosystem.Methods We carried out an in-situobservation on the water and carbon fluxes and environmental factors in a Quercus variabilisplantation using eddy covariance techniques and the micrometeorological observation system.The effects of biophysical factors on the gross primary productivity(GPP),evapotranspiration(ET),and IWUE during 2021-2022 were analyzed.Important findings GPP,ET,and IWUE showed obvious seasonal variations.GPP and ET in the wet year were 7.9%and 21.0%higher than those in the normal year,respectively,whereas IWUE in the wet year was 21.4%lower than that in the normal year.Vapor pressure deficit(VPD)was the main factor affecting GPP in the normal year,and net radiation(R_(n))was the primarily factor limiting GPP in the wet year.ET was mainly determined by Rn in both normal and wet years.Relative extractable soil water(REW)was the main factor regulating IWUE in the normal year,whereas leaf area index(LAI)was the main factor controlling IWUE in the wet year.Environmental factors regulated carbon and water fluxes by affecting canopy conductance,and consequently impacting IWUE.The occurrence of soil drought significantly increased IWUE.The response of GPP and ET to REW showed a time lag of 1 month,while the response of IWUE to REW had no lag.

关 键 词：水分利用效率 干旱 碳水耦合 总初级生产力 蒸散 

分 类 号：S718.5[农业科学—林学]