Partitioning Evapotranspiration in a Cotton Field under Mulched Drip Irrigation Based on the Water-Carbon Fluxes Coupling in an Arid Region in Northwestern China

Measuring evapotranspiration (ET) components in cotton fields under mulched drip irrigation is needed to improve water use efficiency and promote the development of water-saving agriculture. In this study, an Eddy Covariance (EC) system was used observe water-carbon fluxes arid region during two years (2021–2022). The Underlying Water Use Efficiency (uWUE) method partition ET into transpiration (T) evaporation (E) order reveal changing characteristics its analyze effects environmental factors on each component. results showed that diurnal variation same as gross primary productivity (GPP), their course change a bimodal curve at budding, blooming, boll stages. relationship T different growth stages ET, which blooming stage > budding opening seedling stage. were mainly affected by temperature (Tair) net radiation (Rn). This study can provide theoretical practical basis for application uWUE scientific rational allocation resources formulation farmland region.