The effects of soil moisture on the survival of three diazotrophic bacteria species (Azospirillum amazonense, Gluconacetobacter diazotrophicus and Azospirillum brasilense) were tested. Soil moisture had little influence on the survival of A. brasilense, which is considered a free-living species. On the other hand, increased soil moisture extended the survival of the endophytes A. amazonense and G. diazotrophicus. These results indicate that nitrogen-fixing endophytic species are more affected by soil moisture than associative nitrogenfixing species.
Oliveira, A. L. M., Canuto, E. L., Silva, E. E., Reis, V. M., & Baldani, J. I. (2004). Survival of endophytic diazotrophic bacteria in soil under different moisture levels. Brazilian Journal of Microbiology, 35(4), 295–299. https://doi.org/10.1590/S1517-83822004000300005