Deficit irrigation improves maize yield and water use efficiency in a semi-arid environment

Abstract Uncertainty in the availability of water supply pose challenges to traditional irrigation approaches. Regulating the amount and time of irrigation at different crop growth stages could provide a solution to optimize the irrigation water amid drought periods. This study evaluated the effect of different deficit irrigation levels on maize (Zea mays L.) at several growth phases over two growing seasons (2012 and 2013) in Yangling, Shaanxi province of China. Total nine irrigation treatments incorporated three irrigation amount ratios, i.e., control irrigation (CK, 100 % of crop evapotranspiration), and 80 % and 60 % of control irrigation; named as T2–T9. Among the irrigation treatments, grain yield ranged from 6392 to 9362 kg ha–1 and seasonal water use efficiency (WUE) varied from 20.3 to 34.9 kg ha–1 mm–1, whereas the irrigation water use efficiency (IWUE) ranged between 32.0 and 58.1 kg ha–1 mm–1. T2 that received 80 % irrigation between V8 and R6 growth stage had overall higher yield than CK, and this was closely followed by T4 that received 80 % irrigation at growth phase V3-V8 and V11-Tasseling, full irrigation at V8-V11, and 60 % irrigation between Tasseling and Maturity. Due to near optimum growing season temperature in 2013, larger WUE was noted in comparison to 2012, that resulted 16 % larger yield with 10 % lesser ETc, on an average, whereas 2012 growing season had better IWUE because of 37.5 % smaller irrigation consumption. Maize grain yield in response to water stress (Ky, the yield response factor) was 0.66, suggesting that the environmental conditions of the study area favor the application of deficit irrigation. The maize yield response to reduced irrigation supply in this experiment indicated that regulated deficit irrigation might help growers to cope with decline in water availability during growing season.