Effects of Nitrogen on Yield and Nitrogen Efficiency of Silage Corn Hybrid SC. 604 at Different Plant Density

This research was conducted to study the effects of nitrogen application rates, and plant densities on, nitrogen agronomic efficiency, nitrogen use efficiency and nitrogen recovery fraction of grain corn (hybrid SC.604) in 2007 in experimental field of Agricultural college, of Urmia University, Iran. Three nitrogen rates consisting of 100, 200 and 300 kg N ha -1 were chosen as main plots, and three plant densities consisting of 75, 85 and 95 thousands plant ha -1 as sub plots. The results showed that the effect of plant density and nitrogen on grain, biological and protein yield and harvest index was significant. The increase of nitrogen application rate caused significant increase in grain, biological and protein yield and harvest index. The response of grain and protein yield and harvest index to increase in plant density was negative. The results showed that nitrogen agronomic efficiency was higher in plant density of 95 thousand plants with application of 100 kg N ha -1 and Nitrogen use efficiency and nitrogen recovery fraction was higher in 75 thousand plants ha-1 with application of 100 kg N.