Differential effects of two PGPR formulations on groundnut growth, yield, and nodulation under reduced nitrogen amounts

Nitrogen (N) is an essential macronutrient required for peanut growth and productivity. However, excessive nitrogen in agricultural soils is leading to serious environmental pollution and degradation. To address these challenges, sustainable approaches like plant growth promoting rhizobacteria (PGPR) are increasingly explored. Developing sustainable nutrient management strategies that maintain crop performance with lower synthetic nitrogen application is therefore essential for sustainable peanut production. In this study, two PGPR sources (Biozote-max and Biopower) were tested with different nitrogen doses (15 and 30 kg N/ha) to optimize peanut growth and reduce reliance on synthetic nitrogen fertilizers. Glasshouse and field experiments were carried out. Two peanut varieties, NARC-2019 and BARD-479 were used. In glasshouse experiments, morphological and physiological traits and antioxidant enzyme assays were conducted. Also changes in phytochemical and metabolic profiles of peanut plants were assessed. In the field experiment, the yield and yield contributing factors were measured. Contrary to inducing stress, PGPRs, notably Biozote-max, demonstrated positive effects. Combining nitrogen (30 kg N ha − 1 ) and Biozote-max showed remarkable results, with NARC-2019 outperforming BARD-479. No. of nodules increased in both varieties, with the response being markedly higher in NARC-2019 than in BARD-479. Antioxidant enzyme assays yielded non-significant results, suggesting PGPRs’ role in enhancing growth rather than inducing stress. Phytochemical profiling indicated significant influence of PGPR on plant metabolites. Total soluble sugars increased with bacterial inoculation, further enhanced with nitrogen. Field experiments revealed increased yield parameters when PGPRs were applied with 30 kg N/ha. The combined application of PGPR with reduced nitrogen amount (30 kg N/ha) is an effective strategy for improving peanut growth and production while promoting nodulation. This integrated approach holds promise for reducing reliance on synthetic nitrogen fertilizer, thereby contributing to environmental sustainability and reduced agricultural costs.