Response of different maize (Zea mays L.) cultivars grown on a continuously cropped land to nitrogen fertilization at varying times of application in a rainforest agro-ecology

Abstract

Farmers often apply N fertilizer to the soil for high productivity in maize but different maize cultivars may respond differently to time of fertilizer application on a continuously cropped land which is usually characterized with low organic matter and low plant nutrients. A field trial was conducted during 2014, 2015 and 2016 growing seasons at Benin City in Nigeria Rainforest to determine the response of early maturing, late maturing and local maize cultivars to split-applied N at 1 week before sowing (WBS) and 2 weeks after sowing (WAS), 0 and 3 WAS, 1 and 4 WAS, 2 and 5 WAS, and 3 and 6 WAS and Control (without N) on a continuously cropped land. The trial was laid out in a split-plot design with cultivar assigned to main plots and time of N fertilization assigned to the subplots, having three replications. Over three years, grain yield was high when early maize cultivar was fertilized 1 and 4 WAS (av. 3500 kg ha-1) and at 2 and 5 WAS (av. 3700 kg ha-1). For late maize cultivar, high grain yield was obtained when N was applied 1 and 4 WAS (av. 4300 kg ha-1), 2 and 5 WAS (av. 3900 kg ha-1) and 1 WBS and 2 WAS (av. 3800 kg ha-1). For local maize cultivar, grain yield was high when fertilized 1 WBS and 2 WAS (av. 2700 kg ha-1), 2 and 5 WAS (av. 2600 kg ha-1) and 1 and 4 WAS (av. 2500 kg ha- 1). Therefore, different maize cultivars have their appropriate time for fertilizer application to achieve maximum yield on a continuously cropped land.