Effects of time and rate of nitrogen application on phenology and some agronomical traits of maize (Zea mays L.)

Abstract

Maintaining soil fertility and the  use of plant nutrient in sufficient and balanced amounts is one of the key factors in increasing crop yield and decreasing adverse environmental effects and pollutions arising from nonpoint fertilizer usage. The  effects of time and rate of nitrogen application on phenology and some agronomical traits of corn (Zea mays L.) were investigated at the research farm of the University of Mohaghegh Ardabili. The trial was laid out in a split plot design based on a randomized complete block scheme with three replications. Experimental factors were nitrogen fertilizer at four levels (0, 75, 150, and 225 kg ha^–1) in the  main plots and three levels of nitrogen application time [(1/3 at sowing +  1/3 at V_8–10 +  1/3 at tasseling), (1/2 at sowing +  1/2 at tasseling), and (1/2 at sowing +  1/4 at V_8–10 +  1/4 at tasseling) as T₁, T₂, and T₃, respectively] as subplots. The results showed that the maximum values of grain yield and its components, days to 50% tasseling (63.85 days), days to 50% silking (68.2 days), days to physiological maturity (128.9 days) were observed in the plots treated with 225 kg N ha^–1 as T₁. The maximum nitrogen use efficiency (38.16 kg kg^–1) was obtained at application of 75 kg N ha^–1 as T₁, and the minimum values of this index (19.41 kg kg^–1) were obtained in the plots that received 225 kg N ha^–1 as T₂. Based on the results, it was concluded that application of the highest N fertilizer rate (225 kg ha^–1) in three equal splits can be recommended for profitable corn production.