The research was conducted to determine the appropriate application time of nitrogen fertilizer on yield and yield components of sorghum during 2017 and 2018 cropping seasonin Benishangul gumuz region. Treatments consisted of eight application times of nitrogen: all recommended rate of N at planting (T1), ½ at planting + ½ at knee height(T2), Applying 1/2 at planting+1/2 at near flowering (T3), Applying 1/3 at planting+1/3 at knee height+1/3 at near flowering (T4), Applying 1/3 at planting+2/3 at knee height (T5), Applying 1/3 at planting+2/3 at near flowering (T6), Applying 2/3 at planting+1/3 knee height (T7), and Applying 2/3 at planting+1/3 knee height(T8) Days to 50% maturity,harvest and plant height, and grain yield were the parameters significantly affected by treatment effect, while, days to heading, and thousand kernel weight showed non-significant. The maximum grain yield was 5658kg ha-1, in two split applications (1/2 dose at sowing and 1/2 dose at knee height. The highest gross monetary and net monetary return also gained from the application of 1/2 dose at sowing and 1/2 dose at knee height. Therefore, the use of nitrogen in two split applications (1/2 dose at sowing and 1/2 dose at knee height stage) can be recommended for farmers for production of sorghum in the study area and other areas with similar agro ecological conditions.

Keywords: Productivity, Planting time, Sorghum, Nitrogen, Yield, Application time