Nitrogen (N) is considered one of the most important nutrients affectingphenology, growth, yield, and yield components of maize. A field experiment was conducted during the 2020-2022 main cropping seasons to determine the effect of different rates and times of nitrogen applicationson phenology, growth, yield, and yield components of maize. The experiment was laid out in a factorial randomized complete block design with three replications. The experiment consisted of five rates of nitrogen (0, 46, 92,138 and 184kg N ha-1) and three times of application (Full at planting, 1/2 at planting +1/2 at the 5-leave stage, and 1/3 at planting+1/3 at 5-leave stage + 1/3 at booting). Both rate and time of nitrogen application significantly affected the maize phenology, growth parameters and yield components considered, while their interaction significantly affected only numbers of days to 50% silking. The time of nitrogen application (1/3 at planting, 1/3 at the 5-leave stage, and 1/3 at booting) showed highernumber of ears /plant,above ground dry biomass,grain yield andharvest index than did other treatments. The higher nitrogen rate (184kg N ha-1) showed a higher grain yield, while the lower number of ears /plant,above ground dry biomass,grain yield andharvest index were recorded from negative control (0 N kg ). The N in three splits (1/3 at planting, 1/3 at the 5-leave stage, and 1/3 at booting) and 184kg N ha-1produced a higher grain yield with a higher economic return than did the other time-rate nitrogen combinations, suggesting that these time and rate can be used for maize production under rain fed in the study area.

Keywords: Maize, grain yield, partial budget analysis,rate and time of N application.