Role of the earthworm, Eisenia foetida, in affecting organic matter decomposition in microcosms of sludge-amended soil.
Organic matter decomposition was monitored for 49 days at 15 deg C by measuring CO2 fluxes from microcosms in the form of soil cores. Microcosms were amended with activated sewage sludge, Eisenia foetida or both. The organic matter content of microcosms amended with sludge was less where E. foetida was also present than in its absence. The biomass of E. foetida increased only when sludge was added. The redox potential (Eh > 390 mV) indicated oxidizing conditions and no methane was produced. Those microcosms amended with sludge showed an exponential decline in carbon mineralization without E. foetida: the decline was arrested by E. foetida. Labile constituents of sludge were converted to earthworm biomass and respiration. The increase in biomass accelerated sludge stabilization and earthworm activity dispersed the sludge within the soil.