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Plant Science Today (PST)

Research Articles

Vol. 13 No. sp5 (2026): Recent Advances in Agriculture

Improved lentil production and revitalised soil health using liquid formulation of Rhizobium leguminosarum and Bacillus tequilensis in the Indo-Gangetic Plain

DOI
https://doi.org/10.14719/pst.13116
Submitted
8 December 2025
Published
01-07-2026

Abstract

The use of bacterial inoculants as biofertilisers has gained considerable attention in agriculture due to their ability to enhance crop productivity and improve soil fertility. However, the limited shelf life of liquid-based bacterial formulations remains a major constraint to their commercialisation and widespread adoption. To address this challenge, the present study evaluated the effect of different additives on the shelf life of newly developed liquid bacterial formulations and assessed their impact on lentil growth, microbial activity and soil health. In vitro experiments were conducted to determine the influence of various additives on the survival of two bacterial strains, Rhizobium leguminosarum bv. viciae DPR2 and Bacillus tequilensis DPB4. Among the tested combinations, the formulation containing 1.5–2 % polyvinyl pyrrolidone (PVP) supplemented with 1.5 % cassava starch proved to be optimal, significantly enhancing bacterial viability during storage. A field experiment was subsequently carried out to evaluate the agronomic performance of co-inoculation using both bacterial strains in the optimised liquid formulation and to assess its influence on soil microbial activity. The application of liquid biofertiliser treatment (T6), comprising both bacterial strains in the optimised formulation (1.5–2 % PVP + 1.5 % cassava starch), significantly improved plant height, nodule number and other growth attributes of lentil. Furthermore, key soil health parameters including available nitrogen (N), phosphorus (P) and potassium (K), soil microbial biomass carbon (SMBC), CO₂ evolution and dehydrogenase activity were significantly enhanced compared to charcoal-based inoculation and the uninoculated control, indicating increased soil microbial activity. Overall, the findings demonstrate that the optimised liquid formulation (1.5–2 % PVP + 1.5 % cassava starch) effectively extends shelf life and improves the performance of co-inoculated bacterial strains, leading to enhanced lentil growth, soil nutrient availability and microbial activity. These results highlight the potential of this formulation for sustainable agricultural applications.

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