The response of soil macrofauna to OM is particularly marked in low fertility soils (Lowe and Butt, 2002).
The fast turnover of OM in tropical environments and the small amount of litter and fresh OM debris in tropical agro-ecosystems lead to a predominance of endogeic earthworm species (Lavelle and Spain, 2001).
In our study, the experiment was carried out with the endogeic earthworm M. posthuma. Earthworm individuals did not survive in the control treatment.