Abstract
Afield experiment was conducted to investigate the effect of varieties, nitrogen fertilizer levels and their application dates on growth characters of corn (Zea mays L.). The split -split plot design in RCBD with three replications was used. The experiment included two corn varieties (Buhooth 106 and Tallar) and four nitrogen fertilizer levels (0,80,120,160 kg N/ha) and three application dates of fertilizer (half of recommended level was added at sowing and other half after 30 days from sowing, half of recommended level was added at sowing and other half after 60 days from sowing, one fourth of the quantity was added at sowing and half after 30 days from sowing and the last quarter after 60 days from sowing. The varieties ,nitrogen fertilizer levels and application dates, represented as main plot , sub plot and sub-sub plot, respectively. The result indicated that the varieties Buhooth 106 was significantly superior than Tallar variety for grains yield and components with the exception of number of rows per ear and harvest index .Tallar variety was significantly exceeded than Buhooth 106 in crude protien , oil yield and percentage .Increasing nitrogen fertilizer rates caused continuous increase in all grains yield and components and continuous singnificant increase in grain quality with the exception of oil percentage.Application dates of nitrogen affected significantly all grains yield and components. Partitioning nitrogen to three batches gave higer grains yield and components , crude protien and oil .
