Document Type : Complete scientific research article
Authors
1
Yaser Azimzadeh Dryland Agricultural Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Maragheh, Iran
2
Dryland Agricultural Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Maragheh, Iran
10.22069/ejcp.2026.24127.2714
Abstract
Background and objectives: Lentil plays a crucial role in food security, while nitrogen fertilization is key to achieving stable yields in dryland cropping systems. Determining the optimal nitrogen rate for sustainable lentil production under climate variability in semi-arid regions is therefore essential. Although lentil is considered a low-nitrogen-input crop due to its ability to form symbiotic relationships with nitrogen-fixing bacteria, the application of starter nitrogen fertilizer becomes critical in soils with low organic matter content – a common characteristic of most Iranian drylands – to ensure proper crop establishment and yield potential realization. However, the response of lentil to nitrogen under dryland conditions is significantly influenced by annual rainfall fluctuations, and multi-year studies on this topic remain limited in Iran. Accordingly, this study was designed and conducted to evaluate the effects of different urea fertilizer levels on yield stability of two rainfed lentil cultivars (Sana and Bilehsavar) in response to annual climatic variability in the Maragheh region.
Materials and methods: The experiment was conducted as a split-plot arrangement within a randomized complete block design with three replications at the Maragheh Dryland Agricultural Research Station over two growing seasons (2023-2025). Main plots were assigned to lentil cultivars (Sana and Bilehsavar), while sub-plots consisted of nitrogen levels (0, 25, 50, 75, and 100 kg urea ha⁻¹). Following field preparation using minimum tillage with a composite tiller, spring planting was carried out in 10 × 30 m plots using a three-unit ASKE seeder at a planting depth of 5 cm with 17.5 cm row spacing. Urea fertilizer was applied simultaneously with planting through band placement at 5-6 cm depth beneath the seed.
Results: Combined analysis of variance revealed significant (p < 0.01) effects of year, cultivar, and urea levels on all studied traits except harvest index. Significant year × cultivar interactions were observed for grain yield and harvest index, while year × urea interactions affected plant height and biological yield. During the first year with favorable precipitation (381 mm), maximum grain yields of 766 kg ha⁻¹ for Sana and 603 kg ha⁻¹ for Bilehsavar were recorded. However, under reduced rainfall (280 mm) in the second year, yields declined to 622 and 520 kg ha⁻¹ for Sana and Bilehsavar, respectively. Quadratic regression models indicated optimal urea rates ranging between 45-50 kg ha⁻¹ for Sana and 47 kg ha⁻¹ for Bilehsavar to achieve maximum grain yield. Notably, Sana demonstrated significantly higher rain water productivity (1.93 kg ha⁻¹ mm⁻¹) compared to Bilehsavar (1.59 kg ha⁻¹ mm⁻¹).
Conclusion: In summary, the Sana cultivar demonstrated superior adaptation to the variable climatic conditions of the Maragheh region, exhibiting higher yield stability, improved harvest index (44%), and enhanced rain water productivity (1.93 kg ha⁻¹ mm⁻¹). Based on the research findings, the application of 45-50 kg urea ha⁻¹ for the Sana cultivar is recommended as an optimal strategy for achieving sustainable and economic yields in dryland lentil production systems.
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