Bacterial Inoculants Boost Groundnut Growth at Reduced Nitrogen Rates

The work, conducted in glasshouse and field experiments, used two peanut varieties, NARC-2019 and BARD-479, and was designed to test whether bacterial inoculants could help maintain crop performance while cutting reliance on synthetic nitrogen fertiliser.

Nitrogen is an essential macronutrient for peanut growth and productivity, but excessive nitrogen in agricultural soils contributes to serious environmental pollution and degradation. The researchers therefore evaluated the two PGPR sources alongside the reduced nitrogen doses to identify a sustainable nutrient management strategy. In the glasshouse phase, they measured morphological and physiological traits, ran antioxidant enzyme assays, and assessed changes in the phytochemical and metabolic profiles of the plants; the field experiment measured yield and yield-contributing factors.

The results pointed to positive effects rather than stress induction. Biozote-max in particular performed well, and the combination of 30 kg N per hectare with Biozote-max produced the strongest overall response, with NARC-2019 outperforming BARD-479. Nodule numbers increased in both varieties under the treatments, though the response was markedly higher in NARC-2019 than in BARD-479, indicating a clear varietal difference in nodulation response to the combined inoculation and reduced nitrogen regime.

Antioxidant enzyme assays yielded non-significant results, which the authors interpret as evidence that the PGPR formulations enhanced growth rather than inducing oxidative stress in the plants. Phytochemical profiling showed a significant influence of the PGPR treatments on plant metabolites: total soluble sugars increased with bacterial inoculation and were enhanced further when nitrogen was added. In the field experiments, yield parameters improved when the PGPR formulations were applied together with 30 kg N per hectare.

The study concludes that combining PGPR application with a reduced nitrogen rate of 30 kg N per hectare is an effective strategy for improving peanut growth and production while promoting nodulation. The authors suggest this integrated approach holds promise for reducing reliance on synthetic nitrogen fertiliser, contributing to environmental sustainability and lowering agricultural costs. As the findings come from glasshouse and field trials with two peanut varieties under specific reduced nitrogen doses, the reported benefits apply to the tested formulations, varieties and conditions described in the study.

Subject of Research: Effects of two PGPR formulations on groundnut growth, yield and nodulation under reduced nitrogen fertiliser rates

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

Article References: Fatima, H., Bibi, F., Alam, T., Hira, Q. U. A. A., Rafi, A. M., Munir, F., Gul, A., Jahanzaib, M., & Amir, R. (2026). Differential effects of two PGPR formulations on groundnut growth, yield, and nodulation under reduced nitrogen amounts. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10245-x

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10245-x

Keywords: PGPR, groundnut, nitrogen fertiliser, nodulation, Biozote-max, Biopower, NARC-2019, BARD-479, sustainable agriculture, plant growth-promoting rhizobacteria, phytochemical profiling, crop yield