Deficit irrigation maintains maize yield through improved soil water extraction and stable canopy radiation interception

Deficit irrigation (DI) is an effective way to save irrigation water while maintaining sustainable yield in irrigated crops. However, limited information is available related to canopy structure and solar radiation use under DI condition. In this study, our objective was to assess maize hybrids for leaf development, photosynthetically active radiation (PAR) interception and water use under DI condition. Field experiments were conducted in 2016 and 2017 in four maize hybrids at well-watered (I-100, referring to 100% evapotranspiration [ET] requirement) and DI (I-75, referring to 75% ET requirement) water regimes. Compared to I-100, I-75 did not reduce maize biomass and grain yield. Although DI reduced the leaf appearance rates (1.5% in 2016 and 7.6% in 2017) and resulted in greater variations in leaf area index (LAI) among hybrids, the amount of PAR interception was not affected during the growing season. DI significantly reduced the seasonal ET in both years (19.8% in 2016 and 26.6% in 2017). All the hybrids extracted more soil water (29 mm in 2016 and 27 mm in 2017) at I-75 than at I-100. Maize plants at I-75 had greater water use efficiency (WUE) (1.68 kg m(-3)) than those at I-100 (1.41 kg m(-3)). However, DI did not affect radiation use efficiency (RUE). In conclusion, DI at I-75 maintained grain yield through improved soil water extraction and WUE but stable canopy radiation interception and RUE.