Evaluating the effects of biochar and plant growth-promoting bacteria on growth parameters of mustard and rice

Abstract

Soil degradation is a major concern, causing a decline in crop productivity and making sustainable agricultural practices essential for humankind. Biochar and plant growth-promoting bacteria (PGPB) are currently applied as affordable and environmentally safe alternatives. Biochar, a porous, carbon-rich by-product of biomass pyrolysis, was applied at 3 % (w/w) alone (control) and in combination with microbial inoculants, including a bacterial consortium. A 15-day pot experiment was conducted under controlled conditions to evaluate the effects of biochar and plant growth-promoting bacteria (PGPB) on plant growth. This study investigates the effects of biochar and PGPB (three Pseudomonas spp. and one Diaphorobacter spp.) on rice (Oryza sativa L.) and mustard (Brassica juncea L.) when applied individually and in combination. The results were evaluated based on plant growth-promoting criteria namely root and shoot length and chlorophyll content. It was observed that biochar had a positive impact on plant growth parameters when applied individually, however in combination with bacterial inoculants, the results were significantly improved. The consortium treatment showed higher values for root length, shoot length and chlorophyll content compared with individual treatments. This study highlights the major scope and potential of utilising plant growth promoting bacteria and biochar to achieve sustainable increases in plant growth and yield. However, some treatments showed variability in results, which could be attributed to the compatibility between biochar and microbial inoculants. This underscores the need for further optimisation studies on the interaction between biochar and bacterial inoculants.