Response of Spring Wheat (Triticum aestivum) to Deficit Irrigation Management under the Semi-Arid Environment of Egypt: Field and Modeling Study

Samiha Ouda,Juan José Alarcón,Tahany Noreldin,Ragab Ragab,Magdi T Abdelhamid,Gianluca Caruso,Agnieszka Sekara

doi:10.3390/agriculture11020090

Abstract

In many areas of the world, water shortages prevail and threaten food production. Deficit irrigation was commonly investigated in dry areas as a precious and sustainable production approach. Using the CropSyst model to simulate the effects of different deficit irrigation treatments could help draw conclusions and save time, effort, and money. Therefore, the aims of this research were (i) to calibrate and validate the CropSyst model for wheat under different sustained and phenological stage-based deficit irrigation treatments, (ii) to simulate the impacts of the latter treatments on limiting wheat yield reduction. Two field experiments were conducted in Nubaria (Egypt), representing an arid environment. They included seven irrigation treatments: (1) 100%, (2) 75%, or (3) 50% of crop evapotranspiration (ETc) during the whole crop cycle; (4) 50% ETc at tillering only, or (5) at booting only, or (6) at grain filling only, or (7) at both tillering and grain filling, with the replenishment of 100% ETc to the treatments (4) to (7) in the remaining phenological stages. The results revealed that phenological stage-based deficit irrigation of wheat resulted in lower yield reduction compared to sustained deficit irrigation treatments, with a 6% yield reduction when 50% ETc was applied at the booting stage. Wheat yield loss was reduced to 4 or 6% when 95 or 90% of ETc were applied, respectively. The CropSyst model accurately simulated wheat grain and total dry matter under deficit irrigation with low RMSE value. In conclusion, the CropSyst model can be reliably used for evaluating the strategy of planned deficit irrigation management in terms of wheat production under the arid environment.

Highlights

Freshwater resources are under pressure to meet the increasing food demand for the ever-increasing population
The results indicate that reducing the irrigation amount by a certain percentage in the water stress irrigation treatments led to higher irrigation water saving but higher yield losses
We tested the effects of deficit irrigation on different phenological stagebased on field cultivated wheat

Summary

Introduction

Freshwater resources are under pressure to meet the increasing food demand for the ever-increasing population. Under water-stressed conditions, farmers cannot irrigate their cultivated areas with full crop water requirements. Under the latter circumstances, the growing plants suffer from water stress, negatively affecting growth and yield [1,2,3]. To reduce yield losses and use water more efficiently, the deficit irrigation can be practiced to irrigate a crop with less water than the total evapotranspiration [4,5,6]. The phenological stage-based deficit irrigation is a regulated deficit irrigation strategy [8], whose major principle is that plant’s response to regulated deficit irrigation varies with the growth stage, and applying less water during non-critical stages causes no or low yield losses [9]. It was reported that a stage-based deficit irrigation approach could cause an insignificant negative impact on crop productivity [10]

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Results

Conclusion