Simulation-Based Schemes to Determine Economical Irrigation Depths Considering Volumetric Water Price and Weather Forecasts

Exacerbating water and food insecurity in drylands urge the more efficient use of irrigation through volumetric pricing. The optimum depths can be determined using a combination numerical simulation, costs, weather forecasts. In this context, we evaluated effectiveness three simulation-based schemes to determine that maximize net income during each interval WASH_2D model, which simulates flow solute transport plant–soil–atmosphere system. Those were three-point (Scheme A) two-point B) schemes, used optimize depth or two simulated cumulative transpiration at different depths, respectively, considering price forecasts; refilling scheme C), was required return content root zone field capacity. compared with typical tensiometer-based automated D) by carrying out experiment sandy Arid Land Research Center, Tottori University, Japan, major crop, sweet potatoes, 2021. Compared Scheme D, Schemes A, B, C achieved 28%, 7%, 21% higher due applying 26%, 6%, 17% less producing 21%, 5%, 16% biomass, respectively. total A B matched those measured schemes. Both actual evapotranspiration fair agreement observed values. Regarding accuracy forecast, both daily reference rainfall forecasts overestimated, relative RMS error (RMSE) 0.81 0.77 conclusion, two- combined forecasts, prices, demonstrated significant benefits for farmers terms basic types costly systems.