Abstract

Sub-adult earthworms, Eudrilus, Eugenae were cultured for 100 days in rubber containers made from old tyres to determine the plant nutrient release composition in vermicompost using different organic diets. The diets are Andropogon grass + Pig manure (AGPM) Andropogon grass (AG), Bracharia grass + pig manure (BGPM) and Bracharia grass (BG). Result of the study show that the produced vermicompost in each diet consisted mostly of high quality humus with favorable pH level and high cat ion exchange capacity (CEC) which varied with the diets. Pig manure enhanced the CEC of the vermicompost by 114.82%. Available P, exchangeable Ca and Mg were significantly (p = 0.05) increased in the vermicompost and varied among the various diet treatments. Available P was greatest with Andropogon vermicompost relative to the Bracharia vermicompost. Pig manure enhanced the release of available P of Andropogon vermicompost by over 185% and over 1000% in Bracharia vermicompost relative to the grass vermicompost alone. Exchangeable Ca and Mg of Bracharia vermicompost was enhanced 32 and 74% respectively by Pig manure. Results of the study also show increase in earthworm biomass production and cocoon size in the vermicompost which varied among the diet treatments and non-significant difference among the vermicompost in water holding capacity. Weight loss from composition and decomposition rate was highest in BG relative to BGPM, AG and AGPM. Average decomposition rate of the grass diet was 75.25%. Earthworm (Eudrilus eugenae) through its activities increased the rate of decomposition and degradation of organic wastes and is effective in plant nutrient release if subjected to proper culturing with suitable feed materials.

Key words: Eudrilus eugenae, vermicompost, Brancharia grass, Andropogon grass.