Nematode succession during Controlled Microbial Composting

Composting is the heat-producing, aerobe disintegration of organic materials by several organisms which form a complex and fast changing community. Until now only the dynamics of the bacterial community has been thoroughly investigated in relation to decomposing processes. This research focuses on the taxonomical composition and the succession of the nematode community during the composting process. Nematodes show several characteristics which make them ideal bio-indicators to analyze the ecosystem quality. Furthermore, the nematode diversity and density in mature compost are considered crucial to construct a solid soil food web. To characterize the nematode community, a compost heap prepared according to the CMC-method (Controlled Microbial Composting) was surveyed at different time intervals and at the same time several variables (temperature, pH, conductivity and moisture) were determined. The quantitative and taxonomical analyses of the compost samples clearly showed an abundant presence of nematodes in compost (except during the heat peak at more than 71 °C). The most important genera were Rhabditis, Cephalobus, Aphelenchoides, Diploscapter, Panagrolaimus and Mononchoides. Some major shifts in the nematode community occurred during the process. The first nematodes appearing after the heat peak were bacterial feeding enrichment opportunists followed by the bacterial feeding general opportunists. Later in the process fungal feeding nematodes became gradually more important. These apparent temporal changes in nematode community and associated indices illustrate the potential of nematodes to assess the maturity of compos