Deficit drip irrigation based on crop evapotranspiration and precipitation forecast improves water‐ use efficiency and grain yield of summer maize

Abstract

BACKGROUND Limited and erratic precipitation with inefficient irrigation scheduling often leads to an unstable crop yield and low water-use efficiency (WUE) in semi-arid and semi-humid regions. A 2-year field experiment was conducted to evaluate the effect of three irrigation strategies (conventional irrigation (CK), full-drip irrigation (FI), based on crop evapotranspiration and precipitation forecast, and deficit drip irrigation (DI) (75% FI)) on photosynthetic characteristics, leaf-to-air temperature difference (∆T), grain yield, and the WUE of summer maize. RESULTS The results showed that the daily average net photosynthetic rate (Pn) of DI and FI increased by 25.4% and 25.8% at jointing stage in 2018, and 26.3% and 26.5% at grain-filling stage in 2019 compared with CK, respectively. At jointing stage in 2018 and grain-filling stage in 2019, the transpiration rate (Tr) of DI was significantly lower than that of FI (P < 0.05) but there was insignificant difference in Pn value (P > 0.05). The ∆T between 12:00–14:00 of DI and FI was significantly lower than that of CK at jointing stage in 2018 and grain-filling stage in 2019 (P < 0.05). The 2-year average grain yields of DI and FI were 11.4 and 11.5 t ha⁻¹, which increased by 32.4% and 32.8% compared with CK, respectively. The WUE of DI was 2.82 kg m⁻³, which was 17.9% and 33.8% higher than that of FI and CK, respectively. CONCLUSION Deficit drip irrigation based on crop evapotranspiration and precipitation forecast improves crop WUE and maintains high grain yields in semi-arid and semi-humid regions. © 2021 Society of Chemical Industry.