Development of Integrated Fertilizer Prescription Based on STCR- IPNS for Cotton through Inductive Cum Targeted Yield Model in Thirunallar Soil Series of Karaikal, Puducherry, India

The Soil Test Crop Response (STCR) approach within the Integrated Plant Nutrient System (IPNS) is a targeted yield-based strategy that balances immediate crop nutrient needs with long-term soil health, aiming to optimize yield, fertilizer efficiency, and sustainability. Field trials on Typic Haplusterts soils in Karaikal used an inductive cum targeted yield model to develop fertilizer prescription equations (FPE) based on the nutrient requirement (NR) of crops and the contributions from soil (Cs), fertilizers (Cf), and farmyard manure (Cfym). For cotton, desired yield targets of 31, 33, and 35 q ha⁻¹ were set, and nomograms were created to determine precise fertilizer applications based on soil test values. When FYM was applied at 12.5 t ha⁻¹, it contributed 52 kg of nitrogen (N), 30 kg of phosphorus (P2O5), and 48 kg of potassium (K2O), which complemented the calculated NPK fertilizer needs. These values allowed for precise adjustments of nutrient inputs, aligning with both crop demands and the soil’s nutrient-supplying capacity, and improving efficiency while maintaining soil health. This approach provides a practical framework for farmers, enhancing yields and profitability while promoting the sustainable use of resources by balancing "fertilizing the crop" with "fertilizing the soil."