The rate of the decomposition of selected organic waste materials by Lumbricus rubellus

The rate of the decomposition of five organic waste materials (cattle manure, carton shreds, coffee peelings, chayote peelings and banana stalk) as affected by the presence or absence of earthworm (Lumbricus rubellus) was determined and their organic constituents before vermicomposting and 30 and 60 days after vermicomposting compared using the completely randomized design with two replications. The general characteristics of the waste and mean earthworm fresh weights were assessed. At the end of the experiment, all the organic constituents (carbon, nitrogen, organic matter, and crude protein) of all the waste decreased except the nitrogen and crude protein contents of cattle manure which increased during the second month of the decomposition period. The decrease of the organic constituent was, however, significantly higher in the treated media than in the control media. The C:N ratios of the waste also decreased, a result indicating that the decomposition process took place and that it was faster in the treated media. Both the organic constituents and the C:N ratios of the waste exhibited a negative relationship with decomposition time. Regardless of the treatment used, the rate of decomposition was fastest in banana stalk followed in descending order by cattle manure, chayote peelings and carton shreds. During the 60 day duration of the experiment with earthworms, decomposition was hastened to a greater extent foremost in cattle manure by 27 days or 44.72 percent next was carton shreds by 22 days or 37.08 percent, coffee peelings by 21 days or 35.52 percent banana stalk by 19 days or 31.61 percent and chayote peelings by 12 days or 20.40 percent.On the average waste with earthworm decomposed faster by 20 days or 33.86 percent than waste exposed to microorganisms alone. There was no significant difference between the rate of decomposition of the first month and the second month of the study. Changes were observed in the general characteristics (color, odor, size and texture) of the waste during the various periods of decomposition. Mean earthworm weight was heaviest in the cattle manure and coffee peelings media.