ABSTRACT
Although Darwin (1881) ¤rst drew attention to the great importance of earthworms in the decomposition of dead plants and the release of nutrients from them, it was necessary to wait more than a century until this was taken seriously as a ¤eld of scienti¤c knowledge or even a real technology. Vermicomposting is a mesophilic bio-oxidative process in which detritivorous earthworms interact intensively with microorganisms and soil invertebrates within the decomposer community, strongly affecting decomposition processes, accelerating the stabilization of organic matter,
CONTENTS
I What is Vermicomposting? ............................................................................ 53 II Vermicomposting Food Web .......................................................................... 55 III The Process of Vermicomposting ................................................................... 55 IV Effects of Earthworms on Microbial Communities during
Vermicomposting............................................................................................ 56 A Microbial Biomass ................................................................................... 57 B Bacterial and Fungal Growth ................................................................... 59 C Effects of Earthworms on the Activity of Microbial Communities ........ 59 D Effect of Earthworms on Total Coliform Bacteria during
Vermicomposting ..................................................................................... 61 E Effect of Earthworms on the Composition of Microbial
Communities ............................................................................................ 63 V Conclusions .....................................................................................................64 Acknowledgment .....................................................................................................64 References ................................................................................................................65
and greatly modifying its physical and biochemical properties (Edwards and Bohlen 1996; Domínguez 2004; Edwards et al. 2004). Microorganisms produce the enzymes that cause the biochemical decomposition of organic matter, but earthworms are the crucial drivers of the process as they are involved in the indirect stimulation of microbial populations through fragmentation and ingestion of fresh organic matter, which results in a greater surface area available for microbial colonization, thus dramatically increasing microbiological activity. Earthworms also modify microbial biomass and activity through stimulation, digestion, and dispersion in the casts (Figure 5.1) and interact closely with other biological components of the vermicomposting system, thereby affecting the structure of the micro¯ora and microfauna communities (Domínguez et al. 2003; Lores et al. 2006). Thus, the decaying organic matter in vermicomposting systems is a spatially and temporally heterogeneous matrix of organic resources with contrasting qualities that result from the different rates of degradation that occur during decomposition.
