Evaluation of nitrogen use efficiency in intercropping of maize and soybean

In order to investigation nitrogen use efficiency in intercropping of maize and soybean an experiment was conducted with split plot arrangement in a randomized complete block design with three replications in 2012 in Bojnourd (North Khorasan). Nitrogen fertilizer rate was as a main factor at three levels (control, 50 percent lower than recommended N rate, recommended N) and five mixing ratio treatments were (0:100, 50:50, 66:33, 100:0 and 100:25 corn and soybean) as subplots within the main plots. Results indicated that nitrogen and intercropping system had significant effect on yield and nitrogen use efficiency. Nitrogen fertilizer increased nitrogen use efficiency, economical yield and land equivalent ratio. The highest nitrogen use efficiency, economical yield and land equivalent ratio were obtained in mixture of 50:50 corn and soybean under nitrogen recommended rate that 131, 16 and 21 percent higher than sole cropping, respectively. Therefore, intercrops could be used for more efficient use of N on a per land area basis.