Inorganic–Organic Fertilization for Sustainable Rice Production: Enhancing Yield and Soil Fertility

Abstract

The study evaluated the effects of integrated inorganic and organic fertilization on rice yield, nutrient uptake, and soil health over six cropping cycles from 2013 to 2019 in different intensive and diversified rice-based systems in West Bengal, India. A split-plot design was used, which included three cropping sequences: rice-mustard-jute (C1), rice-wheat-maize with greengram (C2), and rice-lentil-sesame (C3). The study examined four nutrient treatments: 100% Recommended Dose of Fertilizers (RDF) using NPK fertilizers; 75% RDF (NPK) combined with 25% nitrogen from biogas slurry (BGS); 50% RDF (NPK) combined with 50% nitrogen (BGS); and 100% nitrogen from biogas slurry (BGS). The legume-based systems (C2 and C3) demonstrated higher rice yields, better nutrient uptake, and improved soil fertility compared to the cereal-oilseed systems. The application of solely inorganic fertilizers (100% RDF) resulted in the highest rice grain yield of 3.25 tons per hectare. However, the combined application of 75% RDF and 25% BGS achieved yields statistically similar to those with 100% RDF, while increasing soil organic carbon levels by 12% and improving nutrient availability. In contrast, the 100% BGS treatment yielded the lowest at 1.73 tons per hectare due to slower nutrient release. Overall, this study highlights that integrated nutrient management, through partial substitution of chemical fertilizers with biogas slurry, is beneficial for soil health without compromising production. The findings underscore the potential of utilizing both organic and inorganic sources within diverse cropping systems to promote sustainability in rice production and enhance long-term soil fertility.