Recent studies on the colony formation of soil bacteria opened the way
to categorize soil bacteria into colony forming curve (CFC) groups of
different growth rates. A bacterial culture collection comprising org
anisms from every CFC group is called an ecocollection (EC). Outlines
of ECs of paddy soil 1992 and grassland soil 1987 and 1992 were descri
bed. Phylogenetic studies by 16S rDNA sequencing showed a great divers
ity of culture strains of the ecocollections. A set of alternative con
cepts was proposed; the active and the quiescent forms of bacterial ce
lls in soil. The former is able to be cultivated and thus counted by t
he plate method, while the latter is not unless it transforms into the
former. Based on the results several points required for extensive ca
taloguing of soil bacteria were noted.