The researchers studied how different levels of nitrogen fertilizer affected the growth and yield of two hybrid maize varieties in Bangladesh. They found that increasing nitrogen levels led to higher yields, with the highest grain yield achieved with 230 kg of nitrogen per hectare. BARI hybrid maize-9 had the highest yield at 10.99 t/ha, followed by BARI hybrid maize-7 at 10.37 t/ha. This suggests that using 230 kg of nitrogen per hectare is the most economical way to maximize maize yield.