广东湛江桉树人工林碳水通量季节格局及其环境生物控制  

Seasonal Patterns of Carbon and Water Fluxes and Their Environmental Biological Control in the Eucalyptus Plantation in Zhanjiang of Guangdong Province

作　　者：竹万宽[1,2] 王志超 杜阿朋[1] 许宇星[1] Zhu Wankuan;Wang Zhichao;Du Apeng;Xu Yuxing(Research Institute of Fast-Growing Trees,Chinese Academy of Forestry Guangdong Zhanjiang Eucalyptus Plantation Ecosystem Research Station,Zhanjiang 524022;Nanjing Forestry University,Nanjing 210037)

机构地区：[1]中国林业科学研究院速生树木研究所,广东湛江桉树林生态系统国家定位观测研究站,湛江524022 [2]南京林业大学,南京210037

出　　处：《林业科学》2024年第9期18-32,共15页Scientia Silvae Sinicae

基　　金：广东省林业科技创新项目(2022KJCX020);广西科技计划项目(桂科AB23026010);广东湛江桉树林生态系统国家定位观测研究站运行补助项目(KS2024160017);林业生态监测网络平台运行项目数据采集(2024CG232)。

摘　　要：【目的】量化桉树人工林生态系统的碳水通量和组分并揭示其受环境生物因子的调控作用,为提高人工林碳汇评估准确性及深入认识气候变化背景下环境生物因子对人工林碳循环过程的影响提供依据。【方法】在雷州半岛北部,采用涡度相关法(EC)测定桉树人工林碳水通量,并同步监测空气温度(Tair)、饱和水汽压差(VPD)、光合光量子通量密度(PPFD)、土壤温度(Tsoil)、土壤湿度(SM)、降水量(Pre)和归一化植被指数(NDVI)等环境生物因子,分析碳水通量和组分的时间变化及其与环境生物因子的关系。【结果】桉树人工林生态系统总初级生产力(GPP)年均值为2907.87 g·m^(-2)a^(-1)、生态系统呼吸(RE)年均值为1509.77 g·m^(-2)a^(-1)、净生态系统碳交换(NEE)年均值为-1398.83 g·m^(-2)a^(-1)、生态系统蒸散(ET)年均值为1069.25 mm,表现为碳汇。GPP、RE、NEE、ET昼夜变化呈非对称单峰趋势,峰值和日均值的绝对值均表现为雨季高于旱季。雨季的GPP、RE、ET累积值高于旱季,NEE累积值在旱季和雨季无明显差异。日间NEE变化的主要影响因子为PPFD,当VPD≥15 hPa时NEE积累受到抑制,气温在中等水平(20℃air<27℃)时净碳吸收能力最强。夜间NEE变化主要受Tair影响,SM会影响NEE对Tair响应的敏感性。水分利用效率(WUE)在旱季(3.85 g·kg^(-1))高于雨季(2.61 g·kg^(-1)),年均值为3.22 g·kg^(-1),季节差异主要由ET主导,与Tair、VPD、PPFD存在显著负相关(P<0.05)。【结论】桉树人工林生态系统在旱季、雨季和全年均表现为碳汇,其碳汇状态和强度由GPP主导。NEE变化主要受PPFD调控,高VPD会抑制生态系统净碳吸收,中等水平温度时生态系统净碳吸收能力最强,SM会影响夜间NEE对Tair响应的敏感性。桉树人工林WUE旱季高于雨季,季节差异主要由ET主导,同时受到Tair、VPD、PPFD的共同影响。【Objective】This paper aims to quantify the carbon and water flux components of eucalyptus plantation ecosystem,reveal the regulatory role of environmental biological factors on carbon and water cycle,so as to provide a basis for improving the accuracy of carbon sink assessment of plantation ecosystem and further understanding the impact of environmental and biological factors on carbon cycle of plantation ecosystem under the background of climate change.【Method】The eddy covariance(EC)technique was used to continuously monitor carbon and water fluxes in a typical eucalyptus plantation ecosystem in the northern part of the Leizhou Peninsula.The environmental biological factors such as air temperature(Tair),vapour pressure deficit(VPD),photosynthetic photon flux density(PPFD),soil temperature(Tsoil),soil moisture(SM),precipitation(Pre),and normalized difference vegetation index(NDVI)were simultaneously detected.The temporal variation characteristics of ecosystem carbon and water fluxes and their responses to environmental and biological factors were analyzed.【Result】Annual average values of total primary productivity(GPP),respiration(RE),net ecosystem carbon exchange(NEE)and evapotranspiration(ET)of eucalyptus plantation ecosystem were 2907.87,1509.77,-1398.83 g·m^(-2)a^(-1)and 1069.25 mm,respectively,showing a carbon sink as a whole.The diurnal variations of GPP,RE,NEE and ET showed asymmetric unimodal trend,and the absolute values of peak value and daily average value were higher in rainy season than in dry season.The accumulated values of GPP,RE and ET in rainy season were higher than those in dry season,while the accumulated values of NEE had no significant difference between dry season and rainy season.The main influencing factor of daytime NEE variation was PPFD.When VPD≥15 hPa,NEE accumulation was inhibited,and the net carbon absorption capacity was strongest at moderate temperatures(20℃<Tair<27℃).Nocturnal NEE changes were mainly affected by Tair,and SM was able to affect the sensitivity o

关 键 词：涡度协方差 碳水通量 环境生物因子 水分利用效率 桉树人工林 

分 类 号：S718.55[农业科学—林学]