| The dynamics of mesophilic and thermophilic bacterial population was studied in the bulk soil and rhizosphere of the grass Aristida adscensionis L. in a caatinga of the semi-arid Brazilian Northeast. Mesophilic heterotrophic bacteria, sporeforming bacteria and actinomycetes were significantly more abundant than thermophiles, and their counts were 10(6) - 10(7) CFU g-1 dry soil, showing weak fluctuations over the one-year study period. Thermophiles were below 10(6) CFU g-1 dry soil and, in general, demonstrated stronger fluctuations over the studied period. Among them, thermophilic actinomycetes showed the greatest decline during the dry season. No significant differences in microbial number were observed between bulk and rhizosphere soil. Mesophilic... |
