Integrated nutrient management’s impact on Dahlia cultivation (Dahlia variabilis L.) cv. Zail Singh

The experiment was conducted during the winter season of 2022–2023 at the Horticultural Research Centre, SVPUA&T, Meerut, to evaluate the impact of Integrated Nutrient Management (INM) on Dahlia variabilis L. cv. Zail Singh using a Randomized Complete Block Design (RCBD) with 19 treatments and three replications. Significant differences (P < 0.05) were observed among treatments for vegetative growth, flowering, and soil parameters. Treatment T12 (50% RDF + poultry manure + Azotobacter + VAM) recorded the maximum number of primary branches (9.75), leaf area (97.75 cm²), leaf area index (0.048), chlorophyll index 55.45 mg/m²), and nitrogen index (26.62 mg/m²), showing approximately 81% improvement over the control (100% RDF). T17 (25% RDF + vermicompost + Azospirillium + VAM) produced the largest stem diameter (14.30 mm), stalk diameter (10.30 mm), and flower diameter (18.00 cm). T5 enabled early color break (6.58 days), T10 extended vase life (7.10 days), while T6 and T7 significantly enhanced soil nutrient availability, and T14–T15 improved soil organic carbon, EC, and pH. In contrast, the control (T1) consistently recorded the lowest values across traits. These findings demonstrated that integrating organic manures and bio-inoculants with reduced levels of chemical fertilizers significantly enhanced crop performance and soil health, offering a sustainable strategy for ornamental horticulture.