Severe drought strongly reduces water use and its recovery ability of mature Mongolian Scots pine(Pinus sylvestris var. mongolica Litv.) in a semi-arid sandy environment of northern China  

作　　者：DANG Hongzhong ZHANG Lizhen YANG Wenbin FENG Jinchao HAN Hui CHEN Yiben 

机构地区：[1]Institute of Desertification Studies,Chinese Academy of Forestry,Beijing 100091,China [2]Institute of Resources and Environment,China Agricultural University,Beijing 100094,China [3]Institute of Sand Fixation and Afforestation of Liaoning Province,Fuxin 123000,China [4]Beijing Forestry University,Beijing 100083,China

出　　处：《Journal of Arid Land》2019年第6期880-891,共12页干旱区科学（英文版）

基　　金：supported by the Fundamental Research Funds for the Central Nonprofit Research Institution of Chinese Academy of Forestry (CAFYBB2014MA013);the National Natural Science Foundation of China (31570704);the Major State Basic Research Development Program of China (2013CB429901)

摘　　要：Trees growing in a semi-arid sandy environment are often exposed to drought conditions due to seasonal variations in precipitation, low soil water retention and deep groundwater level.However, adaptability and plasticity of individuals to the changing drought conditions greatly vary among tree species.In this study, we estimated water use(Ts) of Mongolian Scots pine(MSP;Pinus sylvestris var.mongolica Litv.) based on sap flux density measurements over four successive years(2013–2016) that exhibited significant fluctuations in precipitation in a semi-arid sandy environment of northern China.The results showed that fluctuations in daily Ts synchronously varied with dry-wet cycles of soil moisture over the study period.The daily ratio of water use to reference evapotranspiration(Ts/ET0) on sunny days in each year showed a negative linear relationship with the severity of drought in the upper soil layer(0–1 m;P<0.01).The decrease in Ts induced by erratic drought during the growing season recovered due to precipitation.However, this recovery ability failed under prolonged and severe droughts.The Ts/ET0 ratio significantly declined with the progressive reduction in the groundwater level(gw) over the study period(P<0.01).We concluded that the upper soil layer contributed the most to the Ts of MSP during the growing season.The severity and duration of droughts in this layer greatly reduced Ts.Nevertheless, gw determined whether the Ts could completely recover after the alleviation of long-term soil drought.These results provide practical information for optimizing MSP management to stop ongoing degradation in the semi-arid sandy environments.Trees growing in a semi-arid sandy environment are often exposed to drought conditions due to seasonal variations in precipitation, low soil water retention and deep groundwater level.However, adaptability and plasticity of individuals to the changing drought conditions greatly vary among tree species.In this study, we estimated water use（Ts） of Mongolian Scots pine（MSP; Pinus sylvestris var.mongolica Litv.） based on sap flux density measurements over four successive years（2013–2016） that exhibited significant fluctuations in precipitation in a semi-arid sandy environment of northern China.The results showed that fluctuations in daily Ts synchronously varied with dry-wet cycles of soil moisture over the study period.The daily ratio of water use to reference evapotranspiration（Ts/ET0） on sunny days in each year showed a negative linear relationship with the severity of drought in the upper soil layer（0–1 m; P<0.01）.The decrease in Ts induced by erratic drought during the growing season recovered due to precipitation.However, this recovery ability failed under prolonged and severe droughts.The Ts/ET0 ratio significantly declined with the progressive reduction in the groundwater level（gw） over the study period（P<0.01）.We concluded that the upper soil layer contributed the most to the Ts of MSP during the growing season.The severity and duration of droughts in this layer greatly reduced Ts.Nevertheless, gw determined whether the Ts could completely recover after the alleviation of long-term soil drought.These results provide practical information for optimizing MSP management to stop ongoing degradation in the semi-arid sandy environments.

关 键 词：groundwater soil water availability water stress sap flow reference evapotranspiration 

分 类 号：P64[天文地球—地质矿产勘探]