Study of using Azotobacter in reducing nitrogen consumption in production of common bean cultivars in climatic conditions of Langaroud city

Legumes are considered as one of the most important plant sources that rich in protein and after cereals are the second source of human food. Among legumes, beans (Phaseolus vulgaris L.) due to economic value and area under cultivation are first in rank of the world. Nitrogen is one of the most important nutrients needed by plants and plays an important role in increasing yield, but environmental issues, especially increasing the concentration of nitrate in shallow groundwater in northern Iran have led to the use of biofertilizers. The purpose of this experiment was to investigate the effect of using Azotobacter in reducing chemical nitrogen consumption in bean production in northern Iran.

In order to investigate the effect of using Azotobacter and nitrogen fertilizer on yield and yield components of bean cultivars as a split plot in a randomize complete block design with three replications was performed in an experimental farm located in Langaroud city in 2017. The main factor includes two bean cultivars including: = V1 native and = V2 modified Doroud 4803 and sub-factor 6 levels of nitrogen fertilizer and bacteria: = F1 control, F2 = 50 kg N / ha, F3 = 100 kg N / ha, F4 = Application Azotobacter, F5 = Azotobacter + 25 kg N / ha and F6 = Azotobacter + 50 kg N / ha.

The results showed that the effect of cultivar on number of pods in main branch, number of pods in sub-branch, number of seeds per plant, 100-seed weight, seed yield, biological yield, harvest index, plant height and number of leaves per plant were significant. Different levels of fertilizer on the number of pods in the main branch, number of pods in the sub-branch, number of seeds per pod, number of seeds per plant, 100-seed weight, seed yield, biological yield, harvest index, plant height and number of leaves per plant were significant. The interaction between cultivar and fertilizer on pod number per branch, number of seeds per plant, 100-seed weight, seed yield and harvest index was significant. Treatment F3 (100 kg N / ha) and F6 treatment (50 kg N / ha + Azotobacter) in the studied traits showed superiority over other treatments. Seed yield with application of 100 kg / ha nitrogen (F3) and 50 kg N / ha + Azotobacter (F6) were 2585 and 2455 kg / ha in Doroud cultivar, respectively, which increased seed yield by 68% and 66% compared to the control treatment (F1).

According to the results of the study, the highest seed yield was obtained in the improved Doroud cultivar with an average of 2585kg / ha in treatment of 100 kg N / ha and was in one statistical group with application of 50 kg N / ha + Azotobacter. In fact, it is possible to reduce environmental pollution by consuming 50% less nitrogen fertilizer and using inoculation with Azotobacter. Therefore, inoculation treatment with Azotobacter and 50 kg N / ha is the most suitable fertilizer treatment for beans in the experimental area.