Sensitivity of Irrigation Water Requirement to Climate Change in Arid and Semi-Arid Regions towards Sustainable Management of Water Resources

Fouad H Saeed,Mahmoud S Al-Khafaji,Furat A Mahmood Al-Faraj

doi:10.3390/su132413608

Abstract

This study aimed to assess the spatiotemporal sensitivity of the net irrigation water requirement (NIWR) to changes in climate, for sixteen crops widely cultivated in four irrigation projects located in arid and semi-arid regions of Iraq. Using LARS-WG and five GCMs, the minimum and maximum temperature and precipitation were projected for three periods from 2021–2080 with 20-year steps (P1, P2, and P3) under representative concentration pathways (RCPs) 2.6, 4.5, and 8.5. Weather data available for a reference period from 1990–2019 in four representatives’ meteorological stations were used. The climate variables and other required data were inserted into the CROPWAT 8 NIWR tool. Findings revealed that the increase in the NIWR for the considered crops due to climate change falls in the range 0.1–42.4%, 1.8–44.5%, 1.2–25.1%, and 0.7–14.7% for the North Jazeera Irrigation Project (NJIP), Kirkuk Irrigation Project (KRIP), Upper Khalis Irrigation Project (UKIP), and Dalmaj Irri-gation Project (DLIP), respectively. Barley is more susceptible to changes in climate, whereas maize, potato, soybean, and millet are found to withstand changes in climate better than others. The novel outcomes of this study support optimal spatiotemporal allocation of irrigation water requirement and the sustainable management of water resources in a changing climate in arid and semi-arid regions.

Highlights

Irrigated agriculture remains the largest user of surface and ground water, in arid and semi-arid regions where the user rate around 70% [1,2,3]
The lowest rate of increase in ET0 was observed in July, respectively for periods are examined: 2021–2040 (P1), Period 2 (P2), and Period 3 (P3), with 1.8%, 2.4%, and 2.3%; 1.9%, 3.1%, and
The spatiotemporal sensitivity of projected ET0, Re, net irrigation water requirement (NIWR), and irrigation demand were analyzed using CROPWAT 8 in four cultivated areas located in arid and semi-arid climate zones of Iraq for three future periods (P1, P2, and P3) based on three scenarios (RCP 2.6, representative concentration pathways (RCPs) 4.5, and RCP 8.5) of global warming induced greenhouse emissions implemented by the LARS-WG model

Summary

Introduction

Irrigated agriculture remains the largest user of surface and ground water, in arid and semi-arid regions where the user rate around 70% [1,2,3]. The irrigation water requirement of specific crop is largely depending on climate conditions [4,5,6]. Changes in climate patterns related to global warming play crucial roles in determining future agriculture water demand [7,8,9]. Increased surface air temperature related to climate change leads to increased evapotranspiration [10] and depilates soil moisture in the root zone [11,12,13]. In arid and semi-arid regions, the temperature is a primary factor affecting the irrigation water demand in a changing climate [15]

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Discussion

Conclusion