Effect of N fertilizer on growth and yield of soybean at North Khorasan

In order to study the effects of nitrogen fertilizer on yield and growth of soybean (Glycine max L.) an experiment as factorial in RCB design with three replications was conducted during 2006 and 2007 years at North Khorasan. Factors were cultivar (Hobbit, L.W.K., and Williams), and nitrogen fertilizer (0, 50, 100, and 150 Kg N/ha from urea source). Results indicated that cultivar and N fertilizer significantly effected on seed yield. Williams showed the highest seed yield among cultivars. With increasing N fertilizer application, seed yield increased significantly. Among yield components, number of pod per node, significantly affected by N fertilizer. Nitrogen application caused that number of pod increased. Growth analysis indicated that, nitrogen fertilizer caused the increment of dry matter accumulation, crop growth rate, and leaf area index. Also, williams and L.W.K. showed higher growth indices rather than hobbit.