Growth, yield and quality of knol-khol (Brassica oleracea var. gongylodes) as affected by fertilizer management

Abstract

A field experiment was conducted during rabi (winter) season of 2016-2017 at Horticultural Research Center, Department of Horticulture, Chauras Campus, HNB Garhwal University, of Uttarakhand to assess the effectiveness of combined dose of organic manure and fertilizer on knol-khol (Brassica oleracea var. gongylodes) vegetable crop. The study involved twenty treatments viz., no fertilizer control (T₀), recommended doses of fertilizers (RDF) 100% (T₁), RDF 50% (T₂), Azospirillum (T₃), Azotobacter (T₄), Neem cake (T₅), Chicken manure (T₆), RDF 75% + Azospirillum (T₇), RDF 75% + Azotobacter (T₈), RDF 75% + neem cake (T₉), RDF 75% + chicken manure (T₁₀), RDF 50% + Azospirillum (T₁₁), RDF 50% + Azotobacter (T₁₂), RDF 50% + neem cake (T₁₃), RDF 50% + chicken manure (T₁₄), Azospirillum + Azotobacter (T₁₅), Azospirillum + neem cake (T₁₆), Azospirillum + chicken manure (T₁₇), Azotobacter + neem cake (T₁₈), Azotobacter + chicken manure (T₁₉), and neem cake + chicken manure (T₂₀). The results showed that the treatment T7 (RDF 75%+ Azospirillum) is more efficient over other treatments in terms of yield. The highest yield was found (61.83% over control) in treatment T₇ (RDF 75% + Azospirillum) as compared to control (T₀). Different fertilizer-use efficiencies were significantly improved with the application of organic, inorganic and bio-fertilizer over control as well as chemical fertilizer alone. The treatment T₇ (RDF 75% + Azospirillum) showed maximum nutrient use efficiency and the minimum value was recorded in T₂ (RDF 50%) > T₁ (RDF 100%) > T₁₇ (Azospirillum + chicken manure) > T₁₅ (Azospirillum + Azotobacter) > T₅ (neem cake) and T₀ (control). Study concluded that the combination of organic manure and bio-fertilizer improved the growth and yield of knol-khol (Brassica oleracea var. gongylodes) plant. Therefore, the application of organic manure and bio-fertilizers are recommended for knol-khol production.