Nweke IA and Ogugua Udoka V
Soils of south eastern Nigeria are generally characterized by low fertility and structural defects due to high erosivity and poor management practices. Earthworms are most important soil organism in terms of their influence on plant litter decomposition, nutrient cycling and availability of resources for some other soil organisms, but detailed study on these roles have received very little attention in the study area. This study was therefore an attempt to assess changes in soil physico-chemical properties as induced by Keffia nigeriense (Kn) activities. Two earthworm conditions, Keffia nigeriense cast (Kc), earthworm habitat {soil under Keffia nigeriense activity (Ksi)} and a control {soil outside the area of Keffia nigeriense activities (Kot)} were studied. Composite soil samples were taken from 0-5cm soil depth from the earthworm habitat and control. To determine the quantity of earthworm cast produced a wooden quadrant was used for the daily collection of earthworm cast. The physical and chemical properties were analyzed and the characteristics of both the soil and casts described. The result of the study showed that daily earthworm cast production varies from 0.120 – 0.603 tha-1 day-1 when daily evapo transpiration was minimal 0.3 – 0.6mm/cm2. Kn activities increased the soil total porosity by 7 % and decreased soil bulk density by 8 %. The buffering capacity and pH result showed a trend of Kc > Ksi > Kot, the CEC of the soil increased 3 folds and electrical conductivity 8 folds with Kn activities compared to where there is no Keffia nigeriense activity. The soluble mineral cation values of the soil under Keffia nigeriense activities was 100% and the casts value was 569.6%. The earthworm worked soil (casts) recorded the least value in exchangeable acidity but with highest value of base saturation among the treatments. The result of this study showed that Keffia nigeriense is very effective in plant nutrient release and amelioration of soil physicochemical properties, therefore proper culturing and study should be intensified in the studied area with a view to promote soil fertility and crop performance.
