Analysis on water use efficiency of Populus euphratica forest ecosystem in arid area

Water use efficiency (WUE, the ratio of gross primary productivity (GPP) to evapotranspiration (ET)) reflects coupled relationship between water loss and carbon gain in process plant photosynthetic assimilation. As a dominant tree species arid area, Populus euphratica plays an important ecological role slowing desertification. Here, continuous observations carbon, water, energy fluxes were carried out forest with eddy covariance (EC) technique 2018. We systematically explained variation characteristics WUE at different time scales, explored main controlling factors drought-stressed environment based on synchronous meteorological data. Results showed that exchange ecosystem occurred mainly during growing seasons (April–October). During this period, entire appeared as sink potential sequester atmospheric dioxide. The average daily was 2.2 g C/kg H2O, which lower than other temperate forests (2.57–6.07 H2O) but higher grassland, wetland, cropland. also concluded increase dioxide concentration (CCO2) air relative humidity (RH) could promote WUE. Nevertheless, negatively correlated temperature (Ta), photosynthetically active radiation (PAR), normalized difference vegetation index (NDVI). Additionally, increased under moderate soil content (SWC), decreased due continuously rising SWC. more strongly affected by affecting consumption uptake. Under conditions high temperature, strong low summer, growth rate ET much larger GPP. This study not only contributes our understanding dynamics provides reference for conservation restoration regions.