Question

The fixation of free nitrogen by bacteria in the soil protein is only done by

• A. Azotobacter
• B. Nitrosomonas
• C. Nitrobacter
• D. Thiobacillus

Answer 1

The correct option is A Azotobacter

Leguminous plants require a large amount of nitrogen for their proper growth and development. The soil in which they grow does not provide enough nitrogen It is present in air but it is not in the absorbable form as it is free nitrogen. Roots of legumes contain nodules that provide habitat to a large number of Azobacter. These bacteria convert atmospheric nitrogen into soluble and absorbable forms like nitrites and nitrates that fulfil the nitrogen requirement of plants.