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چکیده
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Drought stress is one of the most significant environmental stresses, leading to various changes in the physiological processes of plants. This study evaluated the effects of regulated deficit irrigation (RDI) and partial root-zone drying (PRD) strategies on physiological parameters, leaf mineral composition, and soil chemical properties in fig (Ficus carica L.) trees in the form of a randomized complete block design with three replications in the field. Irrigation scenarios in five treatments, including full irrigation to the amount of water available in the soil as a control (FI), partial root zone drying at the level of 75% of full irrigation (PRD75), partial root zone drying at the level of 50% of full irrigation (PRD50), regulated deficit irrigation of 75% of full irrigation (RDI75), and regulated deficit irrigation of 50% of full irrigation (RDI50). Compared to full irrigation (FI), soil–plant analysis development values increased by 8.6% and 10.3% under PRD50 and PRD75, respectively, while relative water content rose by 6.5% under PRD75. Electrolyte leakage decreased by 15.2% under PRD75 compared to RDI75, indicating improved membrane stability. The highest water use efficiency was recorded under PRD50, representing a 19.8% increase relative to FI. Leaf nitrogen and phosphorus concentrations increased by 12.7% and 9.4%, respectively, under PRD treatments, while potassium and magnesium were highest under PRD75, with increases of 14.2% and 11.5%, respectively. Soil electrical conductivity and sodium adsorption ratio increased by 18.6% and 22.1%, respectively, under PRD50 compared to FI, while soil pH remained relatively stable (<2% change). Phosphorus and calcium accumulation in the 0–20-cm soil layer increased by 21.4% and 16.8%, respectively, under PRD treatments. Principal component analysis distinguished between irrigation treatments, showing PRD strategies were associated with improved physiological performance and nutrient uptake. These findings suggest that PRD, particularly at 50–75% of full irrigation, enhances water productivity and stress resilience in fig cultivation under water-limited conditions.
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