The Limiting Effect of Deep Soil Water on Evapotranspiration of a Subtropical Coniferous Plantation Subjected to Seasonal Drought  

作　　者：TANG Yakun WEN Xuefa SUN Xiaomin ZHANG Xinyu WANG Huimin 

机构地区：[1]Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences [2]University of Chinese Academy of Sciences

出　　处：《Advances in Atmospheric Sciences》2014年第2期385-395,共11页大气科学进展（英文版）

基　　金：supported by the Strategic Priority Research Program-Climate Change: Carbon Budget and Relevant Issues of the Chinese Academy of Sciences (Grant No. XDA05050601);the National Natural Science Foundation of China (Grant No. 31070408);the Strategic Program of Knowledge Innovation of the Chinese Academy of Sciences (Grant No. KZCX2EW-QN305)

摘　　要：Seasonal drought is a common occurrence in humid climates.The year 2003 was the driest year during the period 1985-2011 in southeastern China.The objective of this study was to elucidate the impact of the exceptional drought in 2003,compared with eddy flux measurements during 2004-11,on the dynamics of evapotranspiration （ET） and related factors,as well as their underlying mechanisms,in a subtropical coniferous plantation in southeastern China.It was found that daily ET decreased from 5.34 to 1.84 mm during the intensive drought period and recovered to 4.80 mm during the subsquent recovering drought period.Path analysis indicated that ET was mainly determined by canopy conductance and deep soil water content （50 cm） during the intensive drought and recovering drought periods,respectively.The canopy conductance offset the positive effect of air vapor pressure deficit on ET when suffering drought stress,while the canopy conductance enhanced the positive effect of air temperature on ET during the late growing season.Because the fine roots of this plantation are mainly distributed in shallow soil,and the soil water in the upper 40 cm did not satisfy the demand for ET,stomatal closure and defoliation were evident as physiological responses to drought stress.Seasonal drought is a common occurrence in humid climates.The year 2003 was the driest year during the period 1985-2011 in southeastern China.The objective of this study was to elucidate the impact of the exceptional drought in 2003,compared with eddy flux measurements during 2004-11,on the dynamics of evapotranspiration （ET） and related factors,as well as their underlying mechanisms,in a subtropical coniferous plantation in southeastern China.It was found that daily ET decreased from 5.34 to 1.84 mm during the intensive drought period and recovered to 4.80 mm during the subsquent recovering drought period.Path analysis indicated that ET was mainly determined by canopy conductance and deep soil water content （50 cm） during the intensive drought and recovering drought periods,respectively.The canopy conductance offset the positive effect of air vapor pressure deficit on ET when suffering drought stress,while the canopy conductance enhanced the positive effect of air temperature on ET during the late growing season.Because the fine roots of this plantation are mainly distributed in shallow soil,and the soil water in the upper 40 cm did not satisfy the demand for ET,stomatal closure and defoliation were evident as physiological responses to drought stress.

关 键 词：CHINAFLUX EVAPOTRANSPIRATION seasonal drought subtropical coniferous plantation 

分 类 号：S714[农业科学—林学]