Synergistic effects of nitrogen fertilization, irrigation regimes, and beneficial soil microbes on pomegranate growth and quality

Pomegranate (Punica granatum L.) cultivation in arid and semi-arid regions is often limited by poor soil fertility, erratic irrigation practices, and declining soil microbial activity, which together reduce productivity and fruit quality. Although previous studies have examined the independent effects of nitrogen fertilization or irrigation scheduling, the combined influence of nitrogen, irrigation, and soil microbial inoculants on plant growth and fruit quality remains insufficiently explored under arid conditions. To address this gap, a two-year field experiment (2022–23 and 2023–24) was conducted at the Instructional Farm, Agricultural Research Sub-Station, Sumerpur (Pali) Rajasthan, India, to evaluate the synergistic effects of nitrogen levels, irrigation regimes, and microbial inoculation on growth, yield, and quality attributes of pomegranate. Results showed that 100% nitrogen and irrigation at 20% soil-moisture depletion, combined with PGPR + AMF inoculation, significantly enhanced plant height (2.98 m), annual shoot growth (31.1 cm), bloom intensity (43.7), fruit weight (238 g), fruit yield (23.6 kg plant⁻¹), juice content (83.5%), TSS (14.3 °Brix), ascorbic acid (13.8 mg 100 g⁻¹), and soil bacterial population (43.7 cfu g⁻¹), while minimizing premature fruit cracking (7.96%). These findings confirm the hypothesis that integrated nutrient, water, and microbial management has a synergistic effect on pomegranate productivity. The study provides novel evidence supporting the adoption of sustainable, integrated approaches to improve yield and fruit quality in pomegranate grown under water-limited agro-ecosystems.