Impact of Micronutrients Foliar Application on the Growth Traits of Cauliflower (Brassica oleracea var. botrytis L.)

An investigation was conducted during two successive winter season of 2018-19 and 2019-20 at the Agricultural Research farm of Banaras Hindu University, Varanasi, involving sixteen different treatments. These treatments included T1 (Control), T2 (Ammonium Molybdate (Mo) @ 0.20%), T3 (Ammonium Molybdate @ 0.30%), T4 (Ammonium Molybdate @ 0.40%), T5 (Boron @ 0.060%), T6 (Boron @ 0.080%), T7 (Boron @ 0.1%), T8 (Ammonium Molybdate @ 0.20% + Boron @ 0.060%), T9 (Ammonium Molybdate @ 0.20% + Boron @ 0.080%), T10 (Ammonium Molybdate @ 0.20% + Boron @ 0.1%), T11 (Ammonium Molybdate @ 0.30% + Boron @ 0.060%), T12 (Ammonium Molybdate @ 0.30% + Boron @ 0.080%), T13 (Ammonium Molybdate @ 0.30% + Boron @ 0.1%), T14 (Ammonium Molybdate @ 0.40% + Boron @ 0.060%), T15 (Ammonium Molybdate @ 0.40% + Boron @ 0.080%), and T16 (Ammonium Molybdate @ 0.40% + Boron @ 0.1%). These treatments were replicated three times using a Randomized Block Design. A recommended basal dose of nitrogen, phosphorus, and potassium (160:80:120 kg ha-1) was applied using urea, single super phosphate (SSP), and muriate of potash (MOP), respectively, during both years of the experiment. Nitrogen was administered 50% as a basal dose and the remainder at 40 days after transplanting (DAT). The total rainfall during the crop growth period was 29.4 mm in 2018-19 and 93.9 mm in 2019-20. The Snowball-16 variety of cauliflower served as the test crop. Chelated zinc at a concentration of 0.5 g l-1 was applied to all treatments, while boron and molybdenum were applied according to the specific treatment. Other crop management practices were followed as per local recommendations. Results revealed that, the tallest plants, the most leaves per plant, and the highest crop growth rate (CGR) in cauliflower were significantly better with the application of (T16) Ammonium Molybdate at 0.40% combined with boron at 0.1%. This outcome was statistically similar to (T13) Ammonium Molybdate at 0.30% plus boron at 0.1% and (T10) Ammonium Molybdate at 0.20% with boron at 0.1%, surpassing other treatments in both years and in the combined analysis. Future research should focus on optimizing micronutrient spray formulations, application techniques, and cauliflower timing.