Effects of earthworm introduction on soil processes and plant growth

We studied short-term effects of three selected earthworm species on soil physical parameters and the production of Oryza sativa (rice), Arachis hypogea (peanuts) and Zea mays (maize) in short-term pot experiments at Lamto (Cote d'Ivoire). Millsonia anomala significantly compacted the soil and decreased water infiltration whereas Chuniodrilus zielae and Hyperiodrilus africanus had opposite effects, and the association of C. zielae and Millsonia resulted in a moderate compaction. Plants had specific responses to earthworm activities. Arachis did not respond whereas maize had a much higher above ground production and decreased root production and rice produced more roots in the presence of worms. Earthworm species had different effects; the association of M. anomala and C. zielae was the most efficient treatment whereas C. zielae alone, or H. africanus had little effect if any on plant production. (C) 1997 Elsevier Science Ltd.