Optimizing crop production water footprints in the face of water scarcity: a combined experimental and simulation study of wheat in Zimbabwe

Abstract

The optimization of water footprints in crop production is critical, given that agroecosystems currently account for more than 70% of global freshwater use. To achieve this, crop growth models provide insights into the impact of various crop and irrigation management strategies on both crop productivity and water use. This study evaluated the capability of the AquaCrop model in simulating wheat yields, crop water use, and water footprints in the Middle-Manyame Sub-Catchment, Zimbabwe. The model was calibrated and validated using experimental data collected from field experiments. Simulation experiments were conducted to assess the impact of early and late planting, drip and sprinkler irrigation techniques, and no mulch, organic mulch, and synthetic mulch options on the water footprint (WF). The AquaCrop model accurately simulated soil water content, crop water use, crop biomass, and grain yield. Simulation runs showed that early planting reduced WFblue and WFgreen by 25 and 4%, respectively. The lowest consumptive WF was observed with drip irrigation and synthetic mulching. The greatest decline in WFblue and WFgreen (52 and 11%) was simulated under early planting, using drip irrigation and synthetic mulching. Overall, the study highlights the importance of efficient crop and irrigation management practices to reduce water footprints in agroecosystems. HIGHLIGHTS AquaCrop was validated for winter wheat in Zimbabwe for the first time.; AquaCrop accurately simulated canopy cover, grain yield, and water use.; Early planting, drip irrigation, and synthetic mulching reduce the WFblue by 52%.; Early planting, drip irrigation, and synthetic mulching reduce the WFgreen by 11%.; Combining farm trials, experiments, and simulations provides realistic options for optimizing WFs.;

Keywords

• aquacrop model
• crop productivity
• crop water use
• drip irrigation
• water footprints