Effect of reclaimed water irrigation on yield attributes and chemical composition of wheat (Triticum aestivum), cowpea (Vigna sinensis), and maize (Zea mays) in rotation

Irrigating crops with reclaimed water from sewage treatment plants can contribute to the conservation and augmentation of the water resources in arid regions. Many countries in the Middle East, North Africa and Sub-Saharan Africa are suffering from serious water shortages. Three field studies were conducted during the period 2010–2011 to assess yield components and chemical constituents of wheat, cowpea and maize crops grown in rotation with reclaimed water for irrigation in comparison with desalinated and groundwater. The reclaimed water irrigation increased wheat plant height (cm), chlorophyll, leaf area (cm²), leaf length (cm), grain yield (t ha⁻¹) and the water productivity (kg grain m⁻³). It improved all cowpea growth parameters under study except the dry forage yield. Nitrogen was also higher under reclaimed water irrigation in wheat tissue, cowpea pods and maize cobs. Reclaimed water had no effect on the element concentrations in wheat, cowpea and maize except for nickel concentration in wheat plants, and Sodium and Manganese concentrations in maize plants. Using reclaimed water for irrigation increased the yield parameters of wheat, cowpea and maize. However, all the studied element concentrations in wheat, cowpea and maize were within the normal limits after irrigation by reclaimed water. It can be concluded that reclaimed water usage will have significant positive impacts on yield and water productivity.