INFLUENCE OF NITROGEN AND MULCHING ON THE GROWTH AND YIELD OF ONION

Abstract

A field experiment was conducted at the Sher-e-Bangla Agricultural University Farm. Dhaka, Bangladesh during the rabi season from October 2010 to April 2011 to evaluate the influence of nitrogen (N) and mulching (M) on the growth and yield of onion Allium cepa) cv. Taherpuri. The experiment was carried out with the application of four levels of nitrogen viz: 0 (N0) , 60 (N). 120 (N120) and 180 (N180) kg ha" and three types of mulching such as no mulch or control (M0), rice straw (M5) and water hyacinth (Mw) with the following 12 treatment combinations N0M0, N0M5, N0M, N50M0 N60M N120M0, N120M N120M N1,Mo Nj80MS. N180M. This was laid out in randomized complete block design (RCBD) and replicated thrice. The results indicated that growth parameters such as plant height and number of leaves at different days aller transplanting, dry weight of leaf; dry weight of pseudostem and dry weight of root were increased significantly with the application of both nitrogen (N) and mulching (M). As nitrogen, mulching of soil with straw (Ms) and water hyacinth (M) increased the length and diameter of bulb, fresh weight and dry weight of bulb and bulb yield. Interestingly, the bulb yield did not show differences between application of 120 kg N ha" (N 120) and application of ISO kg N ha" (N130) as well as M. and M. The maximum plant height and number of leaves per plant were found in N130M and N120M treatment combination whereas minimum plant height and number of leaves were showed at control. The yield components and yield such as maximum bulb diameter, individual bulb fresh weight and bulb yield were also significantly influenced with the combination of N and M. The results revealed that the highest bulb diameter and individual bulb fresh weight were obtained from N12oM treatment and minimum values were observed in N0N10, control condition. The treatment combination N120M was found to provide with the best bulb yield (12.20 t ha") whereas control, N0M0 showed the lowest yield (5.99 t ha 5. In this study. 103 % increased bulb yield of onion was obtained from the treatment N120M in comparison to N0M0 treatment combination. Based on the above results it can be concluded that the use of 120 kg N ha" along with water hyacinth mulch (N120M) increased onion bulb yield significantly under this locality.