Summary
In order to examine if in Amazonia, earthworms exert the same influence on soil microorganisms observed in other tropical and temperate regions, counts were made of the total number of soil microorganisms in pots containig soil, organic matter and different number of earthworms. In contrast to the behaviour in pots without worms an increase in the total number of microorganisms was observed in all pots containing worms, but did not vary greatly with worm number. The increase in microbial population was considered principally due to the presence of an organic substrates in the worm casts and in consequence was distributed throughout the soil profile of pots with worms.