Abstract
Changes of microbiological characteristics during the revegetation of two naked hill slopes were examined as an index for the recovery of natural environment. The number of bacteria increased and the number of fungi decreased with the lapse of years during the revegetation of the slopes, while there was no clear tendency in the number of actinomycetes. Each ratio among them, i.e., bacteria/fungi (B/F), actinomycetes/fungi (A/F), and bacteria/actinomycetes (B/A), showed a clear tendency of exponential decreases with time. The correlation between the ratios with the physical and chemical properties of the soils was also observed. Among these ratios, B/F reflected the changes of the chemical properties of the soils during the revegetation of the slopes most clearly. Although some kinds of restriction are known to exist, dilution-plate method for the evaluation of soil microorganisms was shown to be effective in this experiment, as it was useful for obtaining the index of soil development on the slopes.
