Influence of integrated nutrient management on growth, yield and quality of Brassica oleracea var. gongylodes cv. White Vienna under Garhwal Hill region

A field experiment was undertaken during the Rabi season of 2016-17 at the Horticultural Research Centre, Chauras Campus, Department of Horticulture, H.N.B. Garhwal University, Srinagar (Garhwal), Uttarakhand, to evaluate the influence of integrated nutrient management (INM) practices on the growth, yield, and quality of knol-khol (Brassica oleracea var. gongylodes cv. White Vienna). The experimental layout followed a randomized block design (RBD) with 20 treatment combinations involving varying proportions of organic manures (neem cake, chicken manure), bio-fertilizers (Azospirillum, Azotobacter), and inorganic fertilizers (Recommended Dose of Fertilizers-RDF) replicated thrice. Results revealed that the treatment T7 (RDF 75% + Azospirillum) was significantly superior in terms of yield, recording a 61.83% increase over the control (T0). This treatment also exhibited the highest nutrient use efficiency among all tested combinations. Furthermore, T7 significantly improved key horticultural traits including early knob initiation, reduced days to harvest, increased knob length, knob diameter, and average knob weight. In quality parameters, the highest total soluble solids (TSS) were recorded under T9 (RDF 75% + neem cake), while the maximum vitamin C content was observed with the application of Azospirillum + Azotobacter (T15). The study underscores the effectiveness of integrating organic and bio-fertilizer inputs with reduced chemical fertilizers in enhancing productivity and produce quality of knol-khol, while contributing to sustainable soil fertility management. Based on these findings, the adoption of INM practices, particularly RDF 75% in combination with Azospirillum, is recommended for sustainable knol-khol cultivation in the hill regions of Uttarakhand.