تاثير تراكم بوته و شيوه مصرف كود نيتروژن بر عملكرد دانه ذرت واجزاء آن

Effects of plant density and nitrogen application methods on yield and yield components of grain maize

A field experiment was carried out to study the effects of plant density, and nitrogen application methods on yield, and yield components of grain maize (Zea mays L.) (SC 704 hybrid) at Bakhtajerd Agric. Exp. Sta., Darab, Iran in 1998. The experiment was conducted as a split plot arranged in randomized complete block design with four replications. Treatments consisted of three plant densities (5.33, 6.67 and 8.82 plants m^-2) as main plots and five N application methods (all N at planting, %z at planting, and the rest as topdressing, 1/3 at planting, and the rest as topdressing, 1/4 at planting, and the rest as topdressing, and all N as topdressing) as subplots. The total applied N was 240 kg N ha-ʹ. OF of Nitrogen topdressing was applied in stages 5-7 leaves, 12-14 leaves, and tassel appearance growth stages. Results showed that increased plant density did not significantly affect the ear number per plant, and harvest index. Increasing plant density from 5.33 to 6.67 plants m^-2 had no significant effect on 1000-seed weight, but seed number per ear, grain, and proteins yield significantly decreased with increased plant density to 8.89 plants m^-2. The highest grain and protein yield were obtained at 6.67 plants r n^-2. Nitrogen application methods had a significant effect on seed number per ear, 1000-seed weight, seed and protein yields. The highest rates were obtained when N was applied as 1/4 at planting, and 3/4 as topdressing which was not significantly different with applying 113 N at planting, and 2/3 as topdressing. It was generally concluded that the highest seed, and protein yields was obtained with planting 6.67 plants m^-2, and applying 1/4 N at planting, and the rest as topdressing.