Effect of plant growth-promoting bacteria Bacillus amylliquefaciens Y1 on soil properties, pepper seedling growth, rhizosphere bacterial flora and soil enzymes

The Bacillus amyloliquefaciens Y1 strain was evaluated for its effects on soil properties, pepper seedling growth, rhizosphere bacterial flora and soil enzyme activities. Y1 solubilised insoluble phosphate, produced chitinase, and released siderophores in plate detection assay. In order to evaluate the plant growth promotion potential in vivo, strain Y1 was grown in media containing chitin powder and complex fertiliser. The pot experiment was conducted by treating pepper seedlings with C1/1 (Y1 culture, 50 ml), C2/3 (Y1 culture, 33 ml), C1/2 (Y1 culture, 25 ml), F1/1 (complex fertiliser, 50 ml), F1/2 (complex fertiliser, 25 ml), and W (water) at 10, 20, 30, 40, and 50 days after transplantation (DAT). Plants receiving Y1 had 52% (C1/2) and 68% (C1/1) more root and shoot biomass than W, and 14% (C1/1) and 18% (C2/3) more compared to F1/1 at 80 DAT. Total numbers of flowers per plant at 80 DAT were found significantly higher with the application of Y1 having 34 (C1/1), 35 (C2/3), and 22 (C1/2) compared to 4 (W), 12 (F1/1) and 10 (F1/2). In addition, chlorophyll content in pepper leaves was found to improve with the application of Y1. Furthermore, Y1 has significantly improved nutritional assimilation of total NPK, population of total culturable bacteria and chitinase producing bacteria and activities of chitinase and dehydrogenase in soil. At 60 and 80 DAT, the number of B. amyloliquefaciens at C1/1, C2/3, and C1/2 ranged from 2.3 × 104 to 4.6 × 104 CFU/g of soil. Our results concluded that B. amyloliquefaciens Y1 has positive effects on soil properties and can be suggested as a bio-fertiliser to minimise fertiliser application in modern agriculture.