Effects of nitrogen fertilizer rates on vegetative growth and yield of lettuce cultivars (Lactuca sativa L.) 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 semi-arid ecology of Northern Nigeria. Treatments were factorial combinations of five nitrogen (urea 46% N) rates (0, 30, 60, 90 and120 kg N ha-1) 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 (120 kg ha-1) 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-1 significantly increased yield of lettuce in compared to control treatment. Cultivar had a significant effect on growth characters like fresh weights, 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.