Irrigation optimization in green asparagus (Asparagus officinalis L.) using the AquaCrop model and evolutionary strategy algorithms

Appropriate irrigation water management has attracted considerable attention because it is crucial to guarantee water and food security worldwide. This study aims to solve a water usage optimization problem for asparagus farming using the Deficit Irrigation Toolbox (DIT) optimization tool and AquaCrop-OS model. Seven irrigation strategies were planned to assess the yield response of asparagus spears in the region near Caborca, Sonora, Mexico. Three of them were defined according to the usual practices of conventional irrigation, and the other four involved the optimization approach. Crop water productivity responses to 750, 1000, 1250 and 1500 mm of supplied water for the crop growing season were generated and assessed for each strategy. Using the irrigation optimization strategy, which involved a defined decision table using the covariance matrix adaptation evolutionary strategy, resulted in increased water productivity, making it the best solution to the optimization problem. A spear yield of 11.3–12.1 t ha⁻¹ was obtained using an irrigation depth of 1200 mm, thus resulting in a reduced irrigation depth of 580–615 mm (>30%) for the 2019 growing season and 130–165 mm (±10%) for the 2020 growing season. The novelty of the study is that by formulating a dynamic optimization problem using the AquaCrop-OS model and DIT, it is demonstrated that the water currently used for irrigation of asparagus crops can be reduced by up to 30%.