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چکیده
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Background. The aggravation of the water shortage problem caused by climate change in drought-prone areas emphasizes the use of climate-smart plants and climate-smart agriculture practices. In this context, it seems that the management of nitrogen fertilizers and controlling the amount of water consumed in crops will be of great importance. Materials and methods. A field trial was aimed to evaluate the phenological, morphological, and yield of chickpea with different doses of nitrogen (0, 20, and 40 kg ha-1) and irrigation regimes (I1: well-watered, I2: rainfed, I3: supplemental irrigation during the flowering, I4: supplemental irrigation during the flowering and seed setting) in chickpea drylands of Kermanshah, west of Iran. Results. Although N application slightly delayed the phenological stages, soil moisture deficiency significantly accelerated flowering and maturity. The highest rooting depth was recorded in I2+N40 conditions and the lack of soil moisture increased the longitudinal growth of the roots. However, the number of root nodules (created by symbiotic relationship) under rainfed (I2) and one-time supplemental irrigation (I3) showed the lowest values of 7.30 and 6.70, respectively. Supplemental irrigation (SI) improved the grain yield components compared to the rainfed condition, but the difference in grain yield between SI and I1 conditions was still evident. The highest amount of vegetative growth and yield was recorded under the conditions of I1+N20 and I1+N40. The highest values of water-use efficiency for grain yield (WUEG) were recorded under I2+N40 conditions. Conclusion. WUEG under rainfed conditions was 41%, 17% and 24% higher than I1, I3, and I4, respectively. The highest biomass-based water use efficiency (WUEB) was obtained under I1+N40 and I2+N0 or N20. Although I4 produced a lower grain yield compared to well-watered conditions (about 400 kg ha-1), due to the water scarcity in the semi-arid regions, I4 with the application of 20 or 40 kg ha-1 of nitrogen is still recommended for small-scale farmers as an efficient smart-agriculture practice.
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