Quantifying winter wheat evapotranspiration and crop coefficients under sprinkler irrigation using eddy covariance technology in the North China Plain

• DOI: 10.1016/j.agwat.2022.108131
• Publication Date: 2023-01-03T15:52:01Z
• Authors: Xuyu Feng; Haijun Liu; Dongxue Feng; Xiaopei Tang; Lun Li; Jie Chang; Josef Tanny; Ronghao Liu
• Keywords: Crop coefficient; Growing season; Bowen ratio; Water balance; Irrigation scheduling

Sprinkler irrigation has been widely used for winter wheat crops in the North China Plain (NCP) to maintain high crop yield and enhance water use efficiency because resources are scarce. Determining accurate evapotranspiration (ETc) coefficient (Kc) of is critical optimizing sprinkler management. In this study, an eddy covariance system was deployed a field measure energy balance components (net radiation Rn, soil heat flux G, sensible H, latent LE) calculate ETc Kc. The growth parameters were also investigated. results showed that closure rate, rate daily (LE + H) (Rn - G), 0.89, indicating sufficient closure. Seasonal total LE accounted 67% available G). seasonal values 434 396 mm during 2019–2020 2020–2021 growing seasons, respectively, which comparable those (400–470 mm) under surface irrigation. mean 0.87, 0.46, 3.24, 4.81, 3.94 day−1 early growth, overwintering, rapid middle, late stages, respectively. corresponding Kc 0.77, 0.47, 1.09, 1.14 0.70. close reported FAO 56 paper. positively related leaf area index (LAI), their relationship fitted as Kc=0.87+0.14lnLAI(R2=0.96) LAI range 1–7, where ln natural logarithm function. measured grain 9100 9857 kg ha−1, productivity (WP) 2.07 2.49 m−3 two Both factors approximately 30% higher than (7200 1.68 m−3) by other studies. Considering ETc, recommended application on NCP. 400–430 obtained study can be make scheduling