Investigating the Interaction of Inoculation of Biological Fertilizers and nitrogen on Soybean growth and yield Under Weed Free and Weedy Check Condition

Inoculation of crops with mycorrhiza fungi and growth-promoting bacteria, due to the high benefits (including increased root area and nitrogen fixation) increase the growth, and also nitrogen due to the important role that in crop growth and development directly increases the seed yield in crops. On the other hand, increasing competition between crops-weeds and reducing the access of crops to resources reduces seed yield. Therefore, this experiment was conducted with the aim of investigating the interaction of mycorrhiza, rhizobium inoculation and nitrogen fertilizer on soybean characteristics under weedy check and weed free conditions. This experiment was conducted in the city of Ali Abad Katoul in 2016. Treatments were included 1- Weed management at two levels of weed free and weedy check, 2- inoculation of biological fertilizer at four levels of non-application (control), inoculation of seeds with Bradyrhizobium japonicum, inoculation of seeds with mycorrhizal fungus Glomus mosseae and co-inoculation with Mycorrhiza and Rhizobium and 3- Application of nitrogen fertilizer (pure) from the source of urea fertilizer at three levels of zero (control), 25 and 50 kg / ha. In this experiment, leaf area and dry matter changes were measured during the growing season and grain yield, biological yield, number of pods per plant, number of seeds per plant and 100 seed weight in soybean plant was measured in Soybean plant (Katoul variety). The results of this experiment showed that the effect of biological fertilizer and the interaction of weed and chemical fertilizer on maximum soybean leaf area index was significant. So that, with increasing application of nitrogen fertilizer in weedy check and weed free treatments, the maximum leaf area index increased, but this increase was higher in weedy check tratments. Also, the results of this experiment showed that the effect of biological fertilizer, nitrogen fertilizer and weed management on yield components and seed yield was significant. So, with increasing application of nitrogen fertilizer, inoculation with biological fertilizer and weed control, number of pods per plant, 100 seed weight and number of seeds per plant increased. seed yield with weed control increased 22.2% and by using 50 kg of pure nitrogen, 16.3% was added to seed yield compared to control. Inoculation with mycorrhizal fungi and rhizobium also increased 8.6% and 13.2% of seed yield, respectively, as compared to the control. In general, the results showed improved growth conditions for soybean (weed control and the use of chemical and biological fertilizers) makes the leaf area and dry matter accumulation during the growing season increase. This increase in leaf area and dry matter accumulation cause increases in yield components of soybean and eventually increased seed yield.