Sustainable Intensification of Rice through Integrated Use of Organic Amendments, Biofertilizers, and Chemical Fertilizers in the Lower Gangetic Alluvial Zone

Abstract

Aims: To evaluate the influence of various nutrient management approaches involving organic amendments, biofertilizer, and chemical fertilizers on soil health and plant health of rice under the lower Gangetic alluvial zone of West Bengal. Study Design: A Randomized Block Design (RBD) was employed with six treatments and four replications. Place and Duration of Study: The study was conducted at the Agricultural Experimental Farm, University of Calcutta, Baruipur, South 24 Parganas, West Bengal during the Rabi season of 2024–25. Laboratory studies were undertaken in the Department of Agricultural chemistry and soil science and Department of Agronomy, University of Calcutta, Kolkata-700019. Methodology: The rice variety MTU 1153 was transplanted at uniform spacing and managed according to standard agronomic practices. Organic manures and biofertilizers were incorporated into the soil before transplanting. The full dose of phosphorus and potassium along with half of the nitrogen was applied as basal, while the remaining nitrogen was top-dressed at 45 days after transplanting. Soil samples were collected from a depth of 0–15 cm and analyzed for soil physico-chemical parameters using standard analytical procedures during various growth stages of rice. Observations on growth attributes of rice were recorded at 30, 60 days after transplanting, and at harvest. Yield and yield attributes were measured from the net plot area and expressed in quintals per hectare. The data were subjected to analysis of variance at a five percent level of significance. Results: Integrated treatments significantly enhanced soil CEC and OC, with T6 (organic amendments +Bio fertilizer+ 100% RDF) recording the highest values. Available nitrogen, phosphorus, and potassium were consistently higher in integrated nutrient treatments compared to sole chemical fertilizers, reflecting improved nutrient retention and slow mineralization from organic sources. Significant variations (p < 0.05) were observed among treatments for growth and yield parameters. The highest plant height (107 cm), Crop growth rate (24.76 g m⁻² day-1), and dry matter accumulation (1266.74 g m⁻²) were recorded at harvest under integrated nutrient management which involved organic amendments, biofertilizer and chemical fertilizer (T5 and T6). Grain yield increased significantly from 3.20 t ha⁻¹ in control to 5.36 t ha⁻¹ in the treatment(T6), while straw yield rose from 5.37 t ha⁻¹ to 7.24 t ha⁻¹. ANOVA confirmed treatment effects were significant (p < 0.05) for all major growth and yield traits. Conclusion: These findings highlight the potential of INM as a sustainable strategy for intensive rice cultivation in Gangetic alluvial soils. Although short-term effects on soil physico-chemical properties were observed, substantial improvements require repeated application over multiple seasons.