Effects of Container Types and Soil Organic Matter Proportions on the Culture of a Tropical Earthworm (Libyodrilus violaceus Beddard, 1891)

Abstract

Earthworms are becoming increasingly useful in solving human and environmental problems. In addition to biomonitoring and soil fertility renewing roles, they are now used as livestock feed, therapeutic agents and soil contaminants remover. It is therefore imperative to encourage more earthworm culture research. The aim of this study was to determine the extent to which container types and soil amendments affect the breeding of Libyodrilus violaceus Beddard, 1891 in the laboratory. The earthworm species was cultured in loamy sandy soil amended with different proportions of cow dung inside earthenware, plastic and wooden pots for a period of twelve weeks in the laboratory. The data generated were subjected to multivariate analysis of variance (MANOVA) using the general linear model (GLM) multivariate tests. These tests indicated that both pot and soil types had significant influence on L. violaceus culture. The effects of pot type was more significant (Lambda = 0.114, p < 0.001) compared to soil type (Lambda = 0.302, p < 0.001). Follow-up univariate analysis of variance indicated that pot type had more significant influence on final earthworm number (F = 68.74, p < 0.001) than the final weight (F = 7.14, p < 0.005). While soil type had a strong significant influence on the final number of earthworms (F = 12.24, p < 0.001), its influence on the final weight was not significant (F = 2.20, p > 0.05). Wooden pot had the highest mean final earthworm number (76.50 ± 20.27), followed by earthenware pot (61.75 ± 16.43). Loamy soil amended with 25% cow dung had the highest mean final earthworm number in the three types of pot, 82.67 ± 11.93, 32.00 ± 7.00, and 94.00 ± 11.53 for earthenware, plastic and wooden pots respectively. These findings imply that if L. violaceus must be cultured ex situ, wooden pot should be preferred above earthenware and plastic, while loamy soil amended with 25% cow dung should be preferred over other soil amendments.