Studies on azotobacters prevailing in Egyptian soils.

Soil samples from different locations in Egypt, representing various types of soils, different degrees of fertility and under various standing crops, were used for isolating Azotobacter strains. Sixty Azotobacter isolates were obtained, and A. chroococcum was found to be the most predominant species (56 isolates), while A. vinclandii was sporadically found (4 isolates). Other species of the genus Azotobacter were not detected in the examined soil samples. Isolates were studied for their morphological, cultural, and physiological properties. Thirteen isolates, differing in morphological features, were selected for studying their pleomorphic character.