Growth and Yield Stability of Maize Varieties (Zea mays L.) as Affected by Different Rates of Nitrogen Fertilizer and Cow Dung in Mubi, Adamawa State, Nigeria

A field experiment to study the growth and yield stability of maize varieties (Zea mays L.) to different rates of nitrogen fertilizer and cow dung in Mubi Adamawa State, Nigeria was conducted in 2014 and 2015 cropping seasons at the Food and Agricultural Organization/Tree crops Plantation (FAO/TCP) Farm of Faculty of Agriculture, Adamawa State University Mubi. Two maize varieties; viz. Quality Protein Maize (QPM) and Extra Early White (EEW) were selected for sowing. They were assigned to the main plots and nitrogen with cow dung assigned to the subplots in a factorial combination with nitrogen at the rates of 0, 60 and 120 kg N ha-1 and cow dung at 0, 1- and 2-ton ha-1 in split plot design. Data were collected on plant height, leaf area per plant, leaf area index and grain yield per hectare. Data collected were subjected to analysis of variance and treatment means were separated using Duncan Multiple Range Test. The result showed that EEW had the highest plant height (190.77 cm), higher leaf area per plant (535.6 cm2) and leaf area index (0.40 cm) than QPM. The effect of nitrogen fertilizer on the growth and yield parameters increased as the nitrogen fertilizer was increased. 120kg N ha-1 gave the highest plant height (195.68 cm) and grain yield (5658.3 kg). The control plot produced the least; 164.77 cm (plant height) and 2662.50 kg ha-1 (grain yield). Application of 1ton ha-1 cow dung exhibited the highest plant height, (95.00 cm), leaf area per plant (518.91 cm2) and leaf area index (0.37 cm). There was an interaction of variety with nitrogen on plant height and grain yield. High interaction of variety with cow dung on plant height and leaf area per plant was recorded. There was an interaction of nitrogen with cow dung on plant height, leaf area per plant and leaf area index. However, there was an interaction of variety with nitrogen and cow dung on plant height, leaf area per plant and leaf area index. Application of 120 kg N ha-1 significantly increased the yield of QPM maize along with 2-ton ha-1 of cow dung.