Efficiency of a novel endophytic fungus based biofertilizer in enhancing rice productivity and reducing the chemical fertilizer use in saline and non-saline coastal regions of Bangladesh

Enhanced soil salinity is a major constraint to rice production in the coastal regions of Bangladesh. Salinity stress impairs nutrient uptake and induces ionic toxicity and osmotic stress, while excessive use of chemical fertilizers degrades soil health and causes environmental pollution. A novel salt-tolerant endophytic fungus, Aspergillus welwitschiae Oc streb1, isolated from the halophytic wild rice Oryza coarctata , exhibited multiple plant growth–promoting traits under both non-saline and 900 mM salt-stress conditions in vitro. These findings suggest that Ocstreb1-based biofertilizer could serve as an eco-friendly and cost-effective alternative to enhance rice productivity under saline conditions. In this experiment, the biofertilizer was prepared using fungal spores produced on wheat bran and subsequently mixed with talcum powder as a carrier. Field trials were conducted following a randomized complete block design (RCBD), incorporating different levels of chemical fertilizer application (0%, 80%, and 100% of the BRRI-recommended NPKSZn rates) in both biofertilizer-treated and untreated plants. Compared with the 100% chemical fertilizer treatment, the combined application of biofertilizer and 80% chemical fertilizer resulted in a comparable yield in Barguna and increased yield of 196.6 kg ha⁻¹ in Satkhira. Profitability analysis showed that this treatment provided an additional economic benefit of USD 48–68 ha⁻¹ over the 100% chemical fertilizer treatment. Moreover, fumonisin B1 levels in grains from biofertilizer-treated plants were negligible. In conclusion, commercial production of this biofertilizer will pave the way for enhancing rice yield with less use of chemical fertilizer while promoting sustainable agricultural practice particularly in areas affected by salinity stress.