The Effect of Municipal Sewage Sludge, Azotobacter, and Azospirillum Application on Some Fatty Acids and Nitrogen Indices in Canola

In order to investigate the effect of municipal sewage sludge, Azotobacter, and Azospirillum on some nitrogen indices and fatty acid composition of Canola, a factorial experiment has been conducted based on randomized complete block design with three replications in the field of South Tehran Water and Wastewater Company during 2016-2017 and 2017-2018. The experiment is a factorial experiment in a randomized complete block design with three replications. The experimental factors include canola seed inoculation in three levels (without inoculation, inoculation with azotobacter, and inoculation with azospirillum) and the use of municipal sewage sludge in five levels (control, recommended fertilizer, 10, 20, and 30 tons of sewage sludge). Results show that the interaction between seed inoculation and sewage sludge treatments on eicosanoic, palmitic, and arachidonic fatty acids has been significant at 1% and on stearic acid at 5%. Aztobacter and 30 tons of sewage sludge treatment (2680 kg/ha) has had the highest grain yield, 23.5% higher than the control treatment (2170 kg/ha). The highest amount of oleic and linoleic acid is obtained from 30 tons of sewage sludge treatment with 61.23% and 18.41%, respectively. Nitrogen uptake efficiency is the highest in fertilizer recommendation treatment with Azotobacter (16.79%). Interaction effects of inoculation and sewage sludge treatments on both trait consumption efficiency and productivity efficiency (agricultural) have been significant in terms of biomass and grain yield. Results indicate that the use of nitrogen fertilizer in proper amount, provided that it is in a timely manner, combined with inoculation could have a greater effect on productivity efficiency (agricultural) index. It can be stated that with appropriate use of sewage sludge, and necessary precautions, it can be a good substitute for nitrogen fertilizers.