A series of 48 greenhouse soil microcosms were established and treated with combinations of sewage sludge, Acer saccharum leaves, and the earthworms Eisenia fetida and Lumbricus terrestris. The microcosms were incubated at constant moisture for 110 days. Samples were then taken and analysed for sludge depth, organic-matter content, and waterstable soil aggregates. Weights of surface leaves and weights and numbers of surviving earthworms were determined for each microcosm. L. terrestris significantly reduced sludge depth and the surface organic-matter content of microcosm soil and significantly increased percentages of 4-mm diameter water-stable aggregates. Leaf litter also significantly reduced sludge depth and increased 4-mm water-stable aggregates. E. fetida inhibited surface feeding by L. terrestris, reduced its 110-day survival rate, and inhibited the production of 4-mm water-stable aggregates in L. terrestris treatments. Numbers of E. fetida increased in L. terrestris treatments. Sludge depth, organic-matter content and water-stable aggregates were not significantly different from controls in E. fetida treatments.
All Science Journal Classification (ASJC) codes
- Agronomy and Crop Science
- Soil Science