Optimization of irrigation management: A multi-objective approach based on crop yield, growth, evapotranspiration, water use efficiency and soil salinity

Abstract

Abstract An innovative approach was developed to optimize plant water requirement, growth and yield parameters in irrigated agriculture considering the constraints of water availability and quality in two different cultivation environments. Eggplant total evapotranspiration and growth parameters were measured at the end of growing seasons in two successive years. In the first year, optimum irrigation conditions, namely, irrigation interval, water salinity, and the cultivation environment (three factors) were determined regarding the measured crop parameters (twelve responses). Optimization was carried out by modeling the parameters using response surface methodology and determining optimum desirability based on a central composite design. The optimum desirability was then used to determine an optimum region by overlaying the parameters. The accuracy of models developed to estimate crop yield, evapotranspiration, water use efficiency, soil salinity, shoot dry weight and fruit diameter was impressive with remarkably high R2, adjusted R2, predicted R2 and adequate precision (higher than 0.81, 0.72, 0.57 and 11.38, respectively). The optimum irrigation interval, water salinity and cultivation environment were 4.56 days, 1.47 ds/m and outdoor environment, respectively, resulting in optimum crop yield (2490.7 g/plant), evapotranspiration (604.76 mm), water use efficiency (3.32 g/(plant-mm)) and soil salinity (5.27 ds/m). In the second year, the experiments were repeated according to the optimum region by focusing on the optimum amounts and the results were quite satisfying. This confirmed that with optimization based on multiple modeling, not only the influence of each factor on a single response could be elucidated but also the optimum amounts were more commonplace for multiple responses combined.