首页|Seasonal and inter-annual variations in carbon fluxes and evapotranspiration over cotton field under drip irrigation with plastic mulch in an arid region of Northwest China

Seasonal and inter-annual variations in carbon fluxes and evapotranspiration over cotton field under drip irrigation with plastic mulch in an arid region of Northwest China

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Xinjiang is the largest semi-arid and arid region in China,and drip irrigation under plastic mulch is widely used in this water-limited area.Quantifying carbon and water fluxes as well as investigating their environmental drivers over cotton fields is critical for understanding regional carbon and water budgets in Xinjiang,the largest cotton production basin of China.In this study,an eddy covariance (EC) technique was used to measure the carbon and water fluxes of cotton field under drip irrigation with plastic mulch in the growing seasons of 2009,2010,2012 and 2013 at Wulanwusu Agrometeorological Experiment Station,a representative oasis cropland in northern Xinjiang.The diurnal patterns of gross primary production (GPP),net ecosystem exchange (NEE) and evapotranspiration (ET) showed obviously sinusoidal variations from June to September,while the diurnal ecosystem respiration (Res) was stable between daytime and nighttime.The daytime hourly GPP and ET displayed asymptotic relationships with net solar radiation (Rnet),while showed concave patterns with raising vapor pressure deficit (VPD) and air temperature (Ta).The increases in hourly GPP and ET towards the maximum occurred over half ranges of VPD and Ta.The seasonal variations of GPP,NEE and ET were close to the cotton phenology,which almost reached the peak value in July.The cumulative GPP averaged 816.2±55.0 g C/m2 in the growing season (from April to October),and more than half of GPP was partitioned into NEE (mean value of-478.6±41.4 g C/m2).The mean seasonal ET was 501.3±13.9 mm,and the mean water use efficiency (WUE) was 1.0±0.1 (mg C/g H2O)/d.The agro-ecosystem behaved as a carbon sink from squaring to harvest period,while it acted as a carbon source before the squaring time as well as after the harvest time.

cottoneddy covariancenet ecosystem exchange (NEE)carbon budgetwater use efficiency (WUE)

Jie BAI、Jin WANG、Xi CHEN、GePing LUO、Hao SHI、LongHui LI、JunLi LI

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State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences,Urumqi 830011, China

Wulanwusu Agrometeorological Experiment Station, Shihezi Meteorological Administration, Shihezi 832003, China

Plant Functional Biology & Climate Change Cluster, University of Technology, Sydney, NSW 2007, Australia

West Light Foundation of the Chinese Academy of SciencesNational Natural Science Foundation of ChinaChinese Academy of Sciences Key Deployment Project

XBBS20111041101101KZZD-EW-08-02-02

2015

干旱区科学
中国科学院新疆生态与地理研究所,科学出版社

干旱区科学

CSTPCDCSCDSCI
影响因子:1.743
ISSN:1674-6767
年,卷(期):2015.7(2)
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