Effect of soil disturbance and nutrient supply on soil-plant NPK dynamics and profitability under DSR

A field experiment titled “Response of Direct Seeded Rice to Tillage and Nutrient Management” was carried out during the kharif season of 2024 at All India Coordinated Research Project, College of Agriculture, Nagpur. The study aimed to assess how various tillage methods and nutrient management practices affect the soil-plant NPK and economics of direct seeded rice. The research site was characterized by vertisols with flat topography and a slightly alkaline pH of 7.3. The soil profile showed moderate organic carbon content (0.63 %), low nitrogen availability (227.52 kg ha⁻¹), moderate phosphorus levels (23.54 kg ha⁻¹), and high potassium content (367.38 kg ha⁻¹). A split-plot design was used for the experiment. The main plots were assigned three different tillage treatments: T1- conventional tillage (ploughing fb single rotavator pass), T2 - reduced tillage (one pass using a cultivator), and T3 - zero tillage while sub-plots included four nutrient management treatments: N1- application of 100 % recommended dose of fertilizers (RDF); N2 - 100 % RDF along with seed treatment using a microbial consortium (Biomix); N3 - 100 % RDF combined with foliar sprays of PDKV Grade-II micronutrients at two critical growth phases (5 ml/l at flowering, 65-70 DAS and 10 ml/l at grain filling, 85-90 DAS) and N4 - an integrated approach using 100 % RDF, Biomix seed treatment, and both foliar applications. In total, the experiment comprised of 12 treatment combinations, each replicated thrice to ensure accuracy and statistical robustness. The findings demonstrated that conventional tillage (T1) significantly enhanced nutrient parameters in the plant, including nitrogen, phosphorus, and potassium levels. This tillage practice also increased the residual availability of NPK in the soil as well as improved gross and net monetary returns and the benefit-cost (B:C) ratio. Among the nutrient management strategies, the integrated approach (N4), which combined the recommended dose of fertilizers (RDF), microbial inoculants and specific micronutrient applications showed superior performance across all measured parameters. While both tillage practices and nutrient management had a significant individual influence on rice growth and yield, their combined interaction did not yield statistically significant effects on the evaluated traits.