Introduction: About 90% of nitrogen fixation is performed by microorganisms. Azotobacters are important free-living nitrogen-fixing bacteria. In this study the role of Azotobacter Chrococcum and Azotobacter Paspali in the growth and productivity of wheat has been investigated. Materials and Methods: The most active Azotobacter Chrococcum and Azotobacter Paspali in fixation of nitrogen in different wheat fields of Fars Province were isolated using Winogradskii culture medium. This randomized study was performed in six replications at outdoors considering the following factors; 1- soil sterile with animal manure and unsterile with animal manure, 2- urea at three levels (no urea, 100 mg urea per kg soil, and 200 mg urea per kg soil), and 3- bacteria type at four levels (no bacteria, Azotobacter Paspali alone, Azotobacter Chrococcum alone, and a mix of both bacteria).Findings: The highest weigh of wheat thousand-seed was seen in pots treated by Azotobacter Chrococcum and Azotobacter Paspali. Pots containing unsterile animal manure had the greatest plant growth and in this regard the difference between various levels of nitrogen fertilizer was significant at 5% level. Discussion and Conclusion: The region’s indigenous Azotobacter Chrococcum enhances more wheat growth through nitrogen fixation compared to the other Azotobacter due to calcareous soil and warm and dry weather of the Province. Organic compounds such as animal manure degrade gradually and enhance the growth and stimulate nitrogen fixation by free-living bacteria such as Azotobacters. The indigenous Azotobacter Chrococcum can also be isolated and used for biologic fertilizers to improve crop yield.
کلید واژگان :Azotobacter, nitrogen fixation, animal manure, wheat
ارزش ریالی : 300000 ریال
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