Survival of Azotobacter spp. in Dry Soils

Dry soils stored in glass containers in the laboratory and protected from contamination for periods of 22 to 24 years yielded numerous colonies of Azotobacter chroococcum and other members of the family Azotobacteraceae. These results were compared with those reported in 1974, and the findings are uniformly consistent in terms of surviving populations. The data prove that these bacteria remain viable after prolonged periods of dormancy in much the same way as do the endospores of gram-positive bacteria.