Waste Conversion to Vermicast by Eisenia foetida Given Four Types of Organic Substrates in the Natural Malaysian Environmental Conditions

The present study was carried out to determine the ability of the earthworm Eisenia foetida to convert four different types of organic wastes into vermicast in the natural Malaysian environmental conditions. The experiment was carried out in the worm house with the ambient temperature recorded as between 26°C-33°C and relative humidity ranged between 65%-80%. The water content of the raw organic matter ranged from 71.0%-95.2%. The highest water content of the substrates was in the shredded banana trunk (95.2%), followed by cafeteria waste (91.0%), shredded newspaper (76.3%)and cow dung (71.0%). The pHKciand pHH2o of the cafeteria waste increased 86.3% and 90.2%, respectively after vermiculture treatment. The increase in pH was the highest when the raw material was acidic (4.16). Only slight increase or decrease (i.e. between 6.7%-17.2%) occurred when the raw materials were slightly alkaline (7.40-7.86). Regardless of types and initial pH of the raw materials, pH of vermicast has shifted to near neutral or more alkaline (6.49-8.35). In general, exponential increase in growth of the earthworm in all the organic wastes tested occurred until the 5th day of vermicomposting and declined thereafter. The trend in growth increment was similar in all types of organic wastes. Weight increment commenced immediately after the worms were inoculated onto the media. Earthworms grown on cafeteria waste showed the highest growth increment, followed by cow dung, shredded banana trunk and shredded newspaper. Cafeteria waste was also found to be the fastest to completely convert to vermicast. The raw materials completely turned to vermicast within 36.2 ±1.3 days for cafeteria waste, 43.8 ± 1.14 days for shredded banana trunk, 47.4 ± 0.84 days for shredded newspaper and 58.2 ± 0.84 days for cow dung. Vermicast production was 41% of the earthworm s body weight per day for cafeteria waste, followed by 34% for banana trunk, 32% for shredded newspaper and 26% for cow dung. In the natural Malaysian environmental conditions, the ability of E. foetida to convert organic waste into vermicast vary with type and quality of the substrate used. Growth increment of E. foetida was paralled with the rate of waste conversion into vermicast, e.g. higher growth increment resulted in faster conversion of wastes into vermicast.