In order to evaluation of plant density and nitrogen fertilizer on yield, yield components and some
other traits of Maize (Zea mays) in Ardabil region, Iran, an split-plot experiment based on randomized complete
block design was conducted with three replications in 2006. Main- plots were allocated to nitrogen levels
(0, 75 and 150 kg haG1) and sub-plots to plant densities (7, 9 and 11 plant mG2). Results showed that increase
in density resulted in increase in yield per hectare and decrease in yield and yield components per plant. Also,
increase in nitrogen application led to increase in yield and yield components. With increasing nitrogen level,
leaf appearance rate was increased and Phyllochron was decreased. Also, with increasing density, Phyllochron
was increased and leaf appearance rate was decreased. The highest leaf appearance rate and the shortest time
for Phyllochron was obtained at 7 plant mG2 and 150 kg haG1 nitrogen treatment. Vegetative growth period was
increased as a result of increase in density and nitrogen. Time of appearance of pollens was decreased with
increasing density and at 11 plant mG2 and 150 kg haG1 nitrogen, this time was longer than other treatments.
Flowering conformity period was decreased with increasing density and nitrogen had no significant effect on
this trait and the longest period was related to 7 plant mG2 and 75 kg haG1 nitrogen. Totally, with increasing
density and nitrogen, yield of Maize was increased.