International Journal of Plant & Soil Science

Background: The extensive use of chemical fertilizers and agrochemicals has led to soil degradation, reduced microbial diversity, increased vulnerability to pests and diseases, and adverse environmental consequences. The excessive dependence on chemical inputs in rice cultivation has resulted in declining soil fertility and environmental concerns, necessitating a shift toward sustainable alternatives.

Aim: This research seeks to provide insights into sustainable agricultural practices that can mitigate the adverse effects of chemical fertilizers while ensuring food security and environmental sustainability.

Methods: A field experiment was conducted at the Department of Agricultural Microbiology, Instructional Cum Research Farm, College of Agriculture, IGKV, Raipur (C.G.), India during the Kharif season of 2023-24. The study aimed to evaluate the impact of bio-fertilizers on rice growth, yield, and soil properties under different nutrient management treatments. The experiment comprised seven treatments, including control (T₁), 100% RDF (T₂), 75% RDF (T₃), and combinations of 75% RDF with bio-fertilizers such as Azospirillum (T₄), phosphate-solubilizing bacteria (PSB) (T₅), potassium-solubilizing bacteria (KSB) (T₆), and an integrated approach combining PSB, KSB, and Azospirillum (T₇).

Results: The study indicated that bio-fertilizer treatments significantly influenced plant height, tiller number, panicle count, biomass accumulation, and grain yield. At 30, 60, and 90 days after transplanting (DAT), T₇ consistently recorded the tallest plants (86.92 cm at 90 DAT), followed by T₂ (87.31 cm), highlighting the role of Azospirillum and KSB in enhancing plant growth. Similarly, T₇ exhibited the highest tiller count (5.33 at 90 DAT) and maximum panicle number (5.13 at 90 DAT), underscoring the beneficial effects of bio-fertilizers in promoting tillering and panicle formation. Grain yield was highest in T₂ (40.60 Q/ha), followed closely by T₇ (40.51 Q/ha), while the control (T₁) had the lowest yield (23.40 Q/ha), demonstrating the importance of nutrient supplementation in rice productivity. The straw yield was significantly higher in T₇ (52.82 Q/ha), further validating the effectiveness of integrating bio-fertilizers with reduced chemical fertilizers. Test weight was also improved, with T₇ (27.43 g) and T₄ (27.03 g) recording the highest values, emphasizing enhanced seed quality.

Discussion: Soil analysis at different growth stages indicated no significant changes in pH and organic matter content but revealed notable improvements in soil nitrogen, phosphorus, and potassium levels at harvest, particularly in bio-fertilizer-treated plots. The microbial inoculation of bio-fertilizers enhanced rhizosphere activity, thereby improving soil-plant interactions, nutrient uptake, and overall crop performance.

Conclusion: The study concludes that the application of bio-fertilizers in combination with 75% RDF (T₇) significantly improves rice growth, yield, and soil health, offering a sustainable alternative to full chemical fertilization.