Optimizing Nitrogen Inputs for Sustainable Wheat Farming in Iran

Efficient nitrogen management is vital to ensuring global food security, especially in arid and semi-arid regions where resource constraints and environmental pressures limit crop productivity. This study investigates nitrogen (N) fertilizer management strategies to enhance yield and nitrogen use efficiency (NUE) in irrigated wheat systems across Iran. The goal is to identify optimal nitrogen application thresholds and practices to maximize productivity and sustainability in wheat farming while addressing regional nitrogen deficits. The research synthesizes data from 27 field-based studies across Iran, employing Boundary Line Analysis (BLA) to establish optimal N application rates. It evaluates base, top-dressing, and split N application strategies, examining their impacts on yield and NUE. Additionally, provincial-level nitrogen fertilizer consumption data from 2019 to 2023 was analyzed to estimate nitrogen fertilizer deficits across different regions. Results indicate that wheat yield responds positively to N levels up to 150 kg N ha⁻¹, beyond which further gains diminish. A base application of approximately 50 kg N ha⁻¹ is critical for early plant development, especially in soils with low organic matter. Top-dressing up to 100 kg N ha⁻¹ was most effective during later growth stages, while split applications significantly improved yield. The spatial analysis revealed considerable variation in nitrogen fertilizer deficits, with some regions experiencing shortages exceeding 70 kg N ha⁻¹, potentially limiting yield potential. The findings recommend precise N management practices tailored to crop demand to optimize productivity and minimize environmental impacts. Addressing nitrogen deficits is crucial for improving wheat yield and ensuring balanced fertilizer distribution across regions. These strategies are essential for promoting sustainable wheat production in Iran’s arid and semi-arid regions.