Effect of Biofertilizers at Different Fertility Levels on Nutrient Content and Uptake by Gobhi Sarson (Brassica napus L.) under Himalayan Region

The field experiment was conducted during Rabi 2022-23 at CSKHPKV Shivalik Agricultural Research and Extension Centre (SAREC), Kangra, Himachal Pradesh to assess the effect of biofertilizers at varying fertility levels on soil properties and nutrient uptake by gobhi sarson. The experiment was conducted in split plot design having main plot treatments, comprised three fertility levels (control, 75% recommended dose of fertilizer (RDF) and 100% RDF) and six treatments of liquid biofertilizers viz. Azotobacter, phosphate solubilizing microorganism (PSMO), potassium mobilizing biofertilizer (KMB), zinc solubilizing biofertilizer (ZSB), NPK consortia + ZSB and control (no biofertilizer) as sub-plots, replicated thrice. Results showed that application of 100% RDF recorded higher N, P, K and Zn content (3.90, 0.58, 0.65% and 34.31 ppm and 0.81, 0.19, 1.35% and 29.36 ppm in seed and straw, respectively) and thereby enhanced their uptake (73.1, 10.9, 12.2 kg ha-1 and 64.3 ppm in seed and 66.4, 16.3, 110.1 kg ha-1 and 240 ppm in straw, respectively). Among biofertilizers, seed inoculation with Azotobacter recorded higher nutrient content and uptake of NPK and Zn by seed and straw; the increase was being (45.29, 45.45, 57.97, 46.80 and 31.34, 37.96, 32.22, 34.66%, respectively) over control (no inoculation). Hence, Azotobacter and PSMO was found to be most efficient biofertilizers.