Effect of different levels of nitrogen, bio-fertilizers and Nano-nitrogen on some qualitative and quantitative traits in soybean (Glycine max L.) in Darab (Fars) region

Background and objectives: Soybean is one of the plants that need large amounts of nitrogen for grain yield production. Todays bio-fertilizers are considered as a best replacement for chemical nitrogen to increase soil fertility and sustained agricultural production. Meanwhile, the use of soybean symbiotic bacteria and nitroxin, which contain the most effective nitrogen-fixing bacteria of the genus Azotobacter and Azospirilium, and nano fertilizers containing nitrogen, have been considered. This study aimed to investigate the effect of different levels of nitrogen, bio-fertilizers and nano-nitrogen on some quantitative and qualitative characteristics of soybean cultivar Williams.
Materials and methods: Experiment was conducted as splilit plot in a randomized complete block design with three replications and 12 treatments in the Fars Research Center for Agriculture and Natural Resources (Darab) in the summer of 2013. The main factor consisted of mineral nitrogen (0, 75 and 150 kg ha-1) as urea and sub plot consisted of nitrogen sources (Rhizobium Japonicum, Nano nitrogen, nitroxin and control). In this study, yield, yield components and seed oil and protein content were measured.
Results: Results showed that interaction of nitrogen and nitrogen source was significant for seed yield, haevest index, the first pod distance from the soli and seed protein content. Maximum seed yield (2018 kg ha-1) was seen in 75 kg ha-1 nitrogen with Rhizobium applicarion and minimum seed yield was seen in 0 kg ha-1 nitrogen. In general with increasing nitrogen application, 1000 seed weight increased. So that the maximum 1000 seed weight (110.98 g) was seen at 150 kg ha-1 nitrogen. Maximum biological yield (4508.4 kg ha-1) related to the use of Rhizobium. The highest harvest index (44.24%) obtained from 75 kg ha-1 nitrogen with Rhizobium. The most distance of the first pods from the soil surface (9.56 cm) was found from 150 kg ha-1 nitrogen with rhizobium. Maximum of the seed protein belonged to the combination tretment of 150kg nitrogen and Rhizobium inoculation. The highest (22.99 %) and the lowest (20.32 %) percentage of seed oil was found in without fertilizer and 150 kg ha-1 nitrogen, respectively. The highest oil yield was seen in Rhizobium (386.31 kg ha-1) treatment.
Conclusion: Generally, for soybean (cv. Williams) production in the Darab region, 75 kg nitrogen consumption with the use of Rhizobium is sugested, wich compared to the consumption of 150 kg ha-1 nitrogen (commonly used in the region), will reduced consumption of chemical nitrogen fertilizer by 50 percent.