Determining Economical Irrigation Depths in a Sandy Field Using a Combination of Weather Forecast and Numerical Simulation

Hassan M Abd El Baki,Haruyuki Fujimaki

doi:10.3390/w13233403

Abstract

Advancement of modern technologies has given numerical simulations a crucial role to effectively manage irrigation. A new numerical scheme to determine irrigation depths was incorporated into WASH 2D, which is a numerical simulation model of crop response to irrigation. Based on two predicted points of cumulative transpiration—water price and quantitative weather forecast—the scheme can optimize an irrigation depth in which net income is maximized. A field experiment was carried out at the Arid Land Research Center, Tottori, Japan, in 2019, to evaluate the effectiveness of the scheme on net income and crop production compared to a tensiometer-based automated irrigation system. Sweetcorn (Zea mays L., Amaenbou 86) was grown in three water balance lysimeters per each treatment, filled with sandy soil. The scheme could achieve a 4% higher net income, due to a 7% increase in green fodder yield, and an 11% reduction in irrigation amount, compared with the automated irrigation method. These results indicate that the numerical scheme, in combination with quantitative weather forecasts, can be a useful tool to determine irrigation depths, maximize net incomes which are farmers’ targets, and avoid large investments that are required for the automated irrigation system.

Highlights

IntroductionOver two billion of the world’s population live in countries facing high water stress [1], which will be increased by half by 2025 [2]
We evaluated a new scheme, presented by Abd El Baki et al [33], which can determine irrigation depths that maximize net incomes by predicting two points of cumulative transpiration at each irrigation event, using weather forecasts (WF) and previous irrigation and weather records since the last irrigation event
Two irrigation schemes, the proposed scheme and automated irrigation were compared in terms of net income considering the price of water

Summary

Introduction

Over two billion of the world’s population live in countries facing high water stress [1], which will be increased by half by 2025 [2]. Still, farmers in those countries have limited knowledge to improve irrigation management. Farmers in those countries have limited knowledge to improve irrigation management They tend to over-irrigate their crops to maximize yield. Such activity could have adverse implications for sustainable water use. Proper use of integrated information of plant, soil, and weather can lead to more efficient management of irrigation

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Conclusion