Agronomic Performance and Soil Chemical Responses of Kharif Rice to Balanced and Reduced P and K Supply in the Red and Lateritic Soils of Paschim Medinipur, West Bengal, India

Abstract

Balanced fertilisation is essential for sustaining rice productivity and maintaining soil fertility, particularly in acidic red and lateritic soils where nutrient availability and retention can be limiting. Although nitrogen is commonly applied to enhance rice growth, its effectiveness depends on an adequate supply of phosphorus and potassium. However, the short-term agronomic, soil-fertility and economic consequences of reducing or omitting phosphorus and potassium under a fixed nitrogen supply remain insufficiently characterised for Kharif rice in Paschim Medinipur, West Bengal. A field experiment was conducted during the Kharif season of 2025 at the Agricultural Experimental Field of Midnapore City College, Paschim Medinipur, West Bengal, India, to evaluate the effects of different NPK combinations on rice (Oryza sativa L.) growth, yield, post-harvest soil chemical properties and economic performance under red and lateritic soil conditions. The experiment was laid out in a Randomised Block Design with seven treatments and three replications. Nitrogen was maintained at 80 kg ha⁻¹ in all fertilised treatments, while P₂O₅ and K₂O were supplied at recommended, reduced or omitted levels. Treatments were T1 (80:40:40), T2 (80:40:20), T3 (80:40:0), T4 (80:20:40), T5 (80:0:40), T6 (80:20:20) and T7 (0:0:0 kg N:P₂O₅:K₂O ha⁻¹). Growth, yield attributes, yield, post-harvest soil pH, EC, organic carbon and available N, P and K, along with economic returns, were assessed. T1 recorded the highest values for most growth and yield attributes. Grain yield was highest under T1 (5.06 t ha⁻¹), followed by T2 (4.84 t ha⁻¹) and T4 (4.73 t ha⁻¹), while T7 recorded the lowest yield (2.19 t ha⁻¹). T1 increased grain yield by 131.1% over the control; however, its yield was statistically comparable with T2 and T4. Treatments involving P or K omission generally reduced growth and yield. Post-harvest soil analysis showed comparatively higher available N, P and K and organic carbon under nutrient-supplied treatments. T1 also recorded the highest gross return (₹139,363 ha⁻¹), net return (₹86,279 ha⁻¹) and B:C ratio (1.63). The study indicates that balanced NPK supply improved rice productivity, post-harvest soil chemical status and economic returns under the experimental conditions, although multi-season and multi-location evaluation is required for wider recommendation.