Earthworm microbiology

Abstract

In the 1950S and 60S, in the heyday of ecosystem energetics, soil zoologists, who had done much to instigate this cult, were keenly disappointed to discover that the direct contribution of the mesofauna to total soil metabolism was negligible. A new goal for soil zoology was perceived ---to demonstrate that invertebrate activity promotes microbial metabolism --- but, like other babies, this proved easy to conceive but hard to deliver. Early work suffered from the limitations of dilution plate counting, selective media and general remoteness from field conditions where there are no pure cultures, temperatures fluctuate and energy sources are limited. Keenly interesting work was done with Collembola which consume fungi at one end and produce neat pellets at the other but earthworms, which in culture aerate the medium with burrows, mix organic and inorganic, living and non-living elements indiscriminately and smear their milieu with mucus, urine and faeces, are distressing subjects for microbiology. There are nevertheless numerous publications on earthworm microflora interactions, last critically reviewed in 1967 (this author) and 1972 (Edwards and Lofty). This chapter assesses present knowledge in this field as it applies to soil biota and to the microflora of other substrates, particularly the organic materials potentially available for vermiculture.