Assessment of the soil fertility index (SFI) for sustainable nutrient management in rice-based cropping systems of Barind tract of West Bengal, India

Assessing soil fertility is essential for efficient land management, especially for the ever-growing global population and shrinking arable land per person. This study aims to assess the soil fertility through the Soil Nutrient Index (SNI) and Soil Fertility Index (SFI), and also determine site-specific NPK requirements of rice-based cropping systems of the Barind Tract. The assessment was based on 12 key soil parameters: pH, electrical conductivity (EC), organic carbon (OC), essential macronutrients (N, P, K and S) and micronutrients (Fe, Cu, Zn, B and Mn). SFI and SNI were developed, and nutrient requirements were calculated using FertiliCalc software. The results indicated that 45.41% of the area had low fertility and 54.49% had moderate fertility levels. To achieve optimal rice yield (5200 kg/ha), the average nutrient requirement was 114 kg/ha (N), 14 kg/ha (P), and 50 kg/ha (K). The key findings of this study revealed that the overall soil fertility status of this soil was deficient and unable to support sustainable rice production and suggested the dosages of nutrients help build up the soil OC content and essential primary nutrients (NPK) for specific soils, and also recommended some endemic and high-yielding varieties with a scoped fertilization strategy for achieving the long-term soil fertility and sustainability of the rice-based cropping system of Barind tract. This research provides valuable insights for farmers, researchers, and policymakers to improve crop productivity, optimize fertilization, and ensure sustainable soil fertility through regular monitoring and adaptive management.