Effects of foliar application of micronutrients on growth, yield and quality of onion

Abstract

A field experiment was conducted to determine the effects of foliar application of micronutrients on growth, yield and quality of onion (Allium cepa L.) cv. Pusa Red. The experiment was laid out in randomized block design with three replications. The treatments consist of foliar sprays of five micronutrients, viz., Cu, Zn, B, Fe, and Mn, each in two concentrations (Cu @ 2 and 4 mg l-1, Zn @ 4 and 6 mg l-1, B @ 1 and 2 mg l-1, Fe @ 100 and 200 mg l-1, Mn @ 1 and 2 mg l-1) along with tap water as control. Two foliar sprays of micronutrients were done at 15 days intervals after 50 days of seedling transplanting. Results were found to be significant in most of the growth, yield and quality contributing parameters of onion. The number of leaves per plant (14.1), plant height (66.9 cm), leaf width (4.3 cm), leaf length (63.9 cm), neck length (1.6 cm), neck diameter (2.0 cm), roots length (8.1 cm), number of roots per plant (162.1), bulb diameter (7.6 cm), plant weight (226.3 g), bulb fresh weight (171.7 g), leaves fresh weight (54.5 g), roots fresh weight (4.2 g), number of scales (12.6), total sugars (6.6%), total soluble solids (14.2%), volume (148.5 ml), specific gravity (1.3), dry weight of bulb (13.2 g), dry weight of leaves (21.0 g), dry weight of roots (2.0 g) and yield ha-1 (419.8 q) were maximum in Zn @ 4 mg l-1 treatment, while treatment Zn @ 6 mg l-1 shows maximum ascorbic acid (17.4 mg/100 g). The results clearly indicated that foliar feeding of Zn @ 4 mg l-1 significantly improved vegetative growth parameters, total yield and quality contents in bulb tissues compared to other micronutrients and control. Foliar spraying of Zn gave the superiority in all measured parameters than other treatments.