Comparative Microbial Analysis of Earthworm Casts Collected From Ikenne, Ogun State, Nigeria

A comparative assessment of the physicochemical parameters and microbial profile of three types of earthworm casts (Pellet, Mass and Turret) were determined. The total viable count (TVC), coliform counts, yeast and mould counts were determined using standard procedures. The pH ranged from 7.8 for Mass cast to 8.6 for Pellet cast. Moisture content of the casts ranged from 29.43% for pellet casts to 47.10% for turret casts. Organic matter was 1.05%, 0.72% and 0.63% for pellet, turret and mass casts respectively. TVC was 4.8 x 107cfu/g, 6.1 x 107cfu/g and 1.2 x 108cfu/g for Mass, Turret and Pellet casts respectively. Pellet cast recorded the highest coliform count (1.5 x 107) while Turret cast the least (7.3 x 106 cfu/g). Mould counts was 8.3 x 106 cfu/g for turret cast and 1.2 x 107cfu/g for pellet and mass casts. The lowest yeasts count was 1.2 x 107cfu/g in mass cast while the highest was 3.8 x 107cfu/g for pellet cast. Microbial distribution in the three casts types showed that Staphylococcus aureus is common to all Cast-types. Citrobacter spp, Pseudomonas fluorescens, Penicillium chrysogenum and S. rosei were isolated from Pellet cast only. Aspergillus fumigatus, Fusarium oxisporum, Pseudomonas aeruginosa and Penicillium oxalicum were isolated from only Turret Cast while Aspergillus terreus, Fusarium compacticum, Klebsiella aerogenes and Streptococcus feacalis were isolated from Mass Cast only. The presence of Bacillus licheniformis in Pellet Cast is an advantage plus for Pellet cast usage since this bacteria contributes to nutrient cycling and displays antifungal activities.Keywords: Pellet cast, Turret cast, Mass cast, Microbial Count

NUTRIENT ANALYSIS OF THREE EARTHWORM CAST-TYPES COLLECTED FROM IKENNE, OGUN STATE, NIGERIA

Three types of earthworm cast, i.e. pellet cast, turret cast and mass cast, were analysed for physicochemical characteristics, nutrient composition and compared with impact on soil fertility. The standard methods of AOAC was used to analyse the pH, moisture content, cast profile, cations (Ca, Mg, Na, K, Mn, Cu and Zn), anions (P, PO4, NO4, NO3, N), Organic Carbon and Organic Matter. Pellet cast recorded a significantly higher pH of 8.60ª¤¡Þ0.01 while the mean pH of 8.09ª¤¡Þ0.01 and 7.81ª¤¡Þ0.01 were obtained for turret and mass cast respectively (p<0.05). On the other hand, pellet cast recorded the lowest moisture content (29.42%) compared with 45.60% and 47.19% obtained for mass cast and turret cast respectively. The % organic matter (1.05ª¤¡Þ0.02), % organic carbon (0.61ª¤¡Þ0.01), % Nitrite (0.008ª¤¡Þ0.001), % Nitrate (0.018ª¤¡Þ0.001), % Nitrogen (0.063ª¤¡Þ0.001) and % Phosphorus (0.39 ª¤¡Þ 0.001) obtained for Pellet Cast were significantly higher (p<0.05) than those obtained for mass and turret casts. Pellet cast had higher Ca (11.04ª¤¡Þ2.80 mg/dL), Mn (113.08ª¤¡Þ38.45 mg/dL) and Zn (8.54ª¤¡Þ2.62 mg/dL) than turret (9.64ª¤¡Þ0.77, 77.0ª¤¡Þ17.02, 6.68ª¤¡Þ1.65 mg/dL) and mass cast types (4.54ª¤¡Þ0.25, 19.12ª¤¡Þ6.82, 2.04ª¤¡Þ0.70) mg/dL). This study indicated that pellet cast has poor water holding capacity whereas it has higher nutrient concentration compared with mass and turret casts. On the overall, pellet cast, mass cast and turret cast all played synergistic role in soil fertility