Climate change and agronomic management: Addressing wheat yield gaps and sustainability challenges in the Mediterranean and MENA regions

Abstract

CONTEXT

Wheat is a crucial crop for food and nutritional security in Mediterranean and MENA regions, yet it faces significant challenges due to high yield variability, low average productivity, and substantial yield gaps. This highlights the urgent need for improved agricultural practices to enhance its productivity and resilience. The region's climate climate change, soil degradation, and water supply variability significantly impact wheat production, requiring innovative and integrated solutions to minimize yield gaps and improve sustainability.

OBJECTIVES

The primary objective of this study is to evaluate the impacts of climate change and agronomic management practices (supplementary irrigation, nitrogen fertilizer, planting date) on wheat yields across diverse agro-ecological zones in the Mediterranean region under current and future climate scenarios.

METHODOLOGY

Using advanced crops modeling DSSAT (Decision Support System for Agrotechnology Transfer) and scenario analysis, wheat yields were simulated under RCP 4.5 and RCP 8.5 climate scenarios for 11 representative sites of 7 countries, for the time periods 2010–2040, 2040–2070, and 2075–2099. Study countries and sites include: Morocco (Rabat-Salé and Marrakech-Safi), Spain (North Aragon), Egypt (Al Garbiyia and North Sinai), Italy (Sardinia), Jordan (Amman and Irbid), Turkey (Ankara and Edirne), and Iran (Zagros). The DSSAT model was calibrated and validated for 11 dominant wheat varieties (one variey per site) to simulate potential and attainable yields and the effect of agronomic practices such as supplemental irrigation, nitrogen application, and seeding dates to identify strategies for sustaining productivity across different locations and countries.

RESULTS AND DISCUSSIONS

Wheat yields across all regions are projected to decline by -18% to -20% under RCP 4.5 and RCP 8.5 by 2040, -28% to -27% by 2070, and -30% to -28% by 2099, compared to historical averages. Arid regions, such as North Sinai (Egypt) and Zagros (Iran), are projected to experience severe yield declines of 60–88% by the end of the century under RCP 8.5. Optimal agronomic practices, including supplemental irrigation (60–100 mm) and nitrogen application (60–120 kg ha⁻¹), improved yields by 30–50% (attainable yield exeeding 6 t ha^-1) and enhanced water productivity by 25–70%. Optimal seeding dates between November 1^st and 30^th were identified as critical, while delayed sowing reduced yields by up to 50%. Nitrogen losses exceeded 60 kg N ha⁻¹ in regions with high nitrogen application rates.

SIGNIFICANCE

Climate change will lead to substantial yield losses compared to historical baselines, particularly under RCP 8.5, emphasizing the urgency of adaptation strategies and climate action. The study highlights the importance of integrated nutrient and water management for sustainable wheat production in the Mediterranean, offering context-specific agronomic recommendations for improving resilience in wheat production in the Mediterranean region. This study highlights the need to prioritize region-specific, data-driven interventions to sustain wheat production and ensure food security in the Mediterranean and MENA regions under changing climatic conditions.