Improving Yield and Water Use Efficiency of Wheat (Triticum aestivum L.) by Regulating Plant-Available Water during Crop Development under Semi-arid Conditions in Pakistan

Scarcity of irrigation water in Pakistan warrants adoption of appropriate practices for maximizing crop water use efficiency that at present is far lower compared with other countries. The objective of this research was to enhance water use efficiency (WUE) and optimize irrigation scheduling for optimal wheat yield under water scarce conditions. Field experiments with different irrigation regimes: rain-fed, optimal irrigation and regulated deficit irrigation at different growth stages were conducted on a deep loam soil for four crop seasons (2008–2012). The results showed that regulated deficit irrigation at less sensitive crop stage(s) could allow up to 25 percent water saving without compromising economic yield. AquaCrop simulations were quite reliable for predictions of crop development (canopy cover and in-season biomass), crop yield, soil water dynamics and thus water productivity under different irrigation regimes. Since water saving through deficit irrigation would allow irrigation of additional crop area, the AquaCrop model can be a useful tool for assessing crop requirements and devising irrigation strategies to enhance water productivity under different scenarios. (author)