Effect of compost and earthworm production on soil properties, growth and dry matter yield of maize in crude oil degraded soil

The effect of compost and earthworm production on soil properties, growth and dry-matter yield of maize in crude oil degraded soil was studied. The treatment consisted of 250 g crude oil degraded soil (DS) and 50 g each of four different compost materials mixed differently with 250 g of degraded soil, and the compost were cassava peels (CP), cassava peels + poultry manure (PC), cassava peels + pig manure (GC) and cassava peels + pig manure + poultry manure (PGC) and 10 pieces of sub-adult earthworms (Eudrilus eugenae) were inoculated to each of the experimental pot after 11 days. The five treatments were replicated four times, data generated were subjected to analysis of variance test and treatment means were separated using least significant difference (LSD0.05). The results of the study indicated significant differences between the treatments in soil and agronomic parameters assessed. The application of compost and earthworm activities increased the plant height, leaf area, and number of leaves at 4 weeks after planting (WAP) and 6 WAP, and dry matter yield of maize. The shoot and root dry matter yield was observed to increase in the order PC > PGC > GC > CP > DS. Earthworm production in this study measured by the number survived and biomass weight showed CP and GC as the best culture for earthworm production in oil degraded soil. The degraded soil (DS) did not record any earthworm survival at harvest. The result of the soil analysis indicated less change in the textural class of the soil, and all the chemical parameters tested were enhanced by the compost and earthworm activities. Based on the results of growth rate and yield components of maize as well as soil chemical properties, the PC and PGC cultures having performed competitively better than the other treatments can be considered useful and adequate with the help of earthworm in reclaiming an oil degraded soil for crop production in a tropical environment like Nigeria.