Alternate furrow irrigation affects yield and water-use efficiency of maize under deficit irrigation

Shortage of fresh water and drought stress are important factors limiting crop productivity in semi-arid and arid regions. Irrigation management needs to be optimised to improve irrigation water-use efficiency (IWUE), and thus, agricultural sustainability in these climates. A field experiment was conducted at two semi-arid locations in Iran to evaluate the impact of irrigation regime (applied after crop evapotranspiration of 70mm (I-70), 100mm (I-100) or 130mm (I-130)) and irrigation method (applied to every furrow (EFI) or variable alternate furrow (AFI)) on yield and IWUE of maize (Zea mays L.). Yield response to irrigation rate was quadratic. Kernel yield was 8476 kg ha(-1) under I-70, and this reduced by 12.3% under I-100 and 27.7% under I-130. Yield reduction due to water stress was attributed to decline in both kernel number and kernel weight. Implementation of AFI resulted in a significant saving in irrigation water. At I-70, 31% less water was used with AFI than with EFI. Irrigation water saving was even greater under I-100 and I-130 when AFI was implemented. Regardless of irrigation regime, IWUE under AFI was always greater than under EFI (1.32 vs 1.03 kgm(-3) for grain and 3.30 vs 2.47 kgm(-3) for biomass production). In addition, plants were shorter with a longer root system under AFI, and the role of carbohydrate remobilisation in kernel filling was greater under AFI consistently among irrigation regimes. The results indicated good potential of AFI for development of water-saving strategies for maize production in semi-arid climates.