Environmental controls on carbon and water fluxes of a wheat-maize rotation cropland over the Huaibei Plain of China

• DOI: 10.1016/j.agwat.2023.108310
• Publication Date: 2023-04-11T16:31:53Z
• Authors: Wanqiu Xing; Lilin Yang; Weiguang Wang; Zhongbo Yu; Quanxi Shao; Shiqin Xu; Jianyu Fu
• Keywords: Water Use Efficiency; Photosynthetically active radiation; Stomatal Conductance; Canopy conductance; Growing season; Water use

It has become increasingly important to quantify carbon and water fluxes due their roles in global warming climate change, particularly for the agroecosystems. However, dynamics of have not been clearly recognized rotation croplands with complex changeable climate. Here, variations net ecosystem productivity (NEP), evapotranspiration (ET) use efficiency (WUE, defined as NEP/ET), responses environmental factors were investigated a wheat-maize cropland across Huaibei Plain China over 2013–2015. The total average NEP, ET WUE respectively 489.1 gC m-2, 315.8 kgH2O 4.4 kg-1H2O wheat 192.5 249.0 3.6 maize, implying that season sequestered more CO2 than maize season. Spring drought summer flood affected respectively. Daily seemed be sensitive changes photosynthetically active radiation (PAR), vapor pressure deficit (VPD), soil content (SWC) canopy conductance (Gc). PAR was dominant factor controlling diurnal NEP ET, while opposite effect VPD on recognized. increasing limited by high VPD, which obviously when exceeded 2 kPa during Maize under solar (> 500 μmol m-2 s-1). WUEs negatively related SWC Gc, sensitivity response Gc increased increase or range. Sub-diurnal against PAR, temperature showed clockwise hysteresis but windspeed counter-clockwise hysteresis, these hystereses mainly caused interplay between evaporative demand moisture supply, photosynthesis allocation