Effect of Irrigation Depth Reduction, Planting Date and Cropping Pattern on Water Productivity in West Lake Urmia, Iran

Abstract

Lake Urmia in Iran has faced extreme water loss in recent years due to overuse and mismanagement of water resources, particularly in agriculture. In this study, three strategies including irrigation depth reduction, changing planting dates and crop rotation in crop patterns of Urmia city were assessed for improvement of water productivity to mitigate the crisis of Lake Urmia. For this purpose, the AquaCrop simulation model was applied. The effects of the three strategies were investigated with four indicators: (i) total water productivity (TWP); (ii) economic water productivity (EWP); (iii) farmers' benefit (FB); (iv) dry yield (DY). The results showed that a 60% reduction of current irrigation depth for winter wheat, winter barley, forage maize and tomato and a 40% reduction for sunflower substantially increased TWP and EWP without considerable reduction in DY and FB. Early planting dates for autumn planting crops (wheat and barley) and delaying planting dates for spring planting crops led to a decreased irrigation requirement and increased benefit from rainfall. For the autumn planting pattern, selecting winter barley reduced water consumption by 2170 m3 ha−1 compared to winter wheat, and for the spring planting pattern, selecting forage maize decreased water consumption by 2080 and 3150 m3 ha−1 compared to sunflower and tomato, respectively. © 2018 John Wiley & Sons, Ltd.