Impact of Plant Growth Promoting Rhizobacteria in Restoring Soil and Crop Attributes

Abstract

Background: To evaluate the effect of selected plant growth promoting rhizobacteria (PGPR) (Paenibacillus polymyxa, Pseudomonas putida and Azospirillum brasilense) and Trichoderma sp. in the restoration of selected attributes of soil fertility and the crop productivity in Indian Vindhyan semi-arid region. Methods: An experiment was conducted at the Rajiv Gandhi South Campus, Banaras Hindu University, with test crop brinjal (Solanum melongena L.). Fourteen treatments: four mono-inoculants (T1 to T4), six bi-inoculants (T5 to T10), two tri-inoculants (T11 and T12), one tetra-inoculant (T13) and control (T14) were included in the present study. Paenibacillus polymyxa, Pseudomonas putida, Trichoderma sp. and Azospirillum brasilense were used in single or in combination in all treatments. Result: The results showed a positive increment in organic C and total N in all treatments. This increase was maximum in T13 (Paenibacillus polymyxa + Pseudomonas putida + Trichoderma sp. + Azospirillum brasilense) treatment followed by T11 greater than T12 greater than T8 greater than T9 greater than T5 greater than T6 greater than T10 greater than T2 greater than T3 greater than T4 greater than T1 compared to control. Positive increment in plant height, number of leaves and flowers were also noted in T13, T11 and T12 treatments. Maximum above-ground biomass and below-ground biomass were recorded in tetra inoculant treatment. Improved nutrient acquisition in T13 (tetra-inoculant) and T11 and T12 (tri-inoculant) treatments is due to increasing nutrient uptake of N from nitrogen-fixing bacteria and uptake of P from phosphate mineralizing. Thus, for restoration of selected soil and crop attributes through PGPR and Trichoderma sp. especially through tetra-inoculants or tri-inoculantsis considered to be a good technique.