Municipal household waste used as complement material for composting chicken manure and crop residues

There are few organic materials available as agricultural soil amendment because their low chemical content means that large quantities are required. In order to improve the availability of raw materials for composting, as well as the quality of the compost produced, municipal solid waste (MW) was added to cotton-seed residue (CSR) and to the association of CSR with chicken manure (M) in different weight/weight (MW/added materials) ratios of 5:1 and 2:1. Aerobic composting was processed and compost yield was determined, as well as compost particle size and pH. Also, the compost bulk density and its water holding capacity were determined as well as contents of total nitrogen, carbon, phosphorus, calcium (Ca), magnesium and heavy metals. According to its pH and carbon/nitrogen ratio values, the municipal waste of Cotonou was judged to be a good raw material for composting in order to improve availability of the organic source of nutrients. The composts produced with MW+M+CSR had the highest potential for amending Ferralsols, especially with a mixture of 2:1 (200 kg MW+100 kg M+100 kg CSR) that could be applied at 10 t ha–1. However, further improvement in composting methods was suggested to increase Ca++ and reduce mercury contents, respectively. Moreover, potassium balance should be improved in the produced compost