EFFECTS OF NITROGEN FERTILIZER RATES ON VEGETATIVE GROWTH AND YIELD OF LETTUCE (Lactuca sativa L.) CULTIVARS AT KADAWA, SUDAN AGRO-ECOLOGICAL ZONE OF NIGERIA

Abstract

The study was carried out to evaluate effects of nitrogen fertilizer on vegetative growth and yield of lettuce (Lactuca sativa L.) cultivars under irrigated conditions during 2016/2017 and 2017/2018 dry seasons in a semiarid ecology of Northern Nigeria at Irrigation Research Sub-Station farm (IRS) of the Institute for Agricultural Research, Ahmadu Bello University, Kadawa, Nigeria. Treatments were factorial combination of five nitrogen rates (0, 30, 60, 90 and 120 kg N ha-1) using urea (46% N) and three lettuce cultivars (Great lake, Lettuce Slaai and Baby leaf mix) laid out in a complete randomized block design (RCBD) with three replicates. The results indicated that different levels of nitrogen fertilizer rates on all growth and yield characteristics were significant with the highest nitrogen level of 120 Kg recording the highest yield of 10.0 and 11.9 tonnes ha-1 in 2016/2017 and 2017/2018 seasons respectively while the control recorded least yield of 4.0 and 5.3 tonnes ha-1 in both seasons. Application of 120 kg N ha significantly increased yield of lettuce in the tune of 52.7% compared to control treatment. Cultivar had a significant effect on growth characters like fresh weight, number of leaves, canopy spread and vegetative yield but not on stem diameter and root length. Great lake significantly out yielded the other two cultivars. The highest yield was obtained with 120 kg ha -1 treatment with Great lake.