Document Type : Research Paper
Authors
1 Assistant Professor, Soil and Water Research Institute, Tehran, Iran
2 Former M.Sc. student of Islamic Azad University of Karaj, Alborz, Iran
3 Member of Young Researchers and Elite Club, Islamic Azad University of Rasht, Gilan, Iran
Abstract
The present investigation was designed to compare the effect of combination biofertilizer of nitrogen fixing free-living bacteria and plant growth promoting bacteria of Azotobacter. It also aimed to compare the effect of Azospirillum alone and in combination with other plant growth promoting bacteria of Pseudomonas fluorescens and Bacillus subtilis with five nitrogen fertilizer levels on the wheat growth indices and yield.The experiment including biofertilizer and different amounts of nitrogen fertilizer was carried out as factorial in completely randomized design with three replications. At the end of plant growth period, some plant indices such as spike and grain number, crop yield, grain to straw weight ratio, straw yield, and grain nitrogen percentage were measured. The results showed that in the simple effect of bio fertilizer, the most effective factor was related to the biofertilizer consortium containing Azotobacter, Azosprillum, Pseudomonas and Baillus subtilis which respectively increased 8, 22.5, 26.5 and 23.3 % the amounts of grain nitrogen, spike number, straw yield and plant yield in comparison with control treatment. Although in the simple effect of chemical fertilizer on studied indices, 100 kg/ha of nitrogen had the most effect, it didn’t demonstrate any significant difference in comparison with the fertilizer level of 75 kg/ha. The highest amounts of measured indices were related to the interaction of bio fertilizer including Azotobacter, Azosprillum, and Pseudomonas and Bacillus subtilis with nitrogen level of 75kg/ha that could respectively increase 25, 100.4, 53.5, 100.6 and 92.6% of grain and spike number, the nitrogen content of grain, straw and plant yield compared to control plant.
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