Performance of Three Epigeic Earthworm Species, Eisenia fetida, Eisenia andrie and Dendrobanae veneta, in Managing Rose and Carnation Wastes in some Selected Ethiopian Flower Farms

Abstract

The horticulture sector in Ethiopia is being challenged by multifaceted hitches; among which managing excess wastes produced from the farms and minimizing the cost of inorganic fertilizers are the major ones. The performance of three epigeic earthworm species, Eisenia fetida, Eisenia andrie and Dendrobanae veneta, in managing flower (rose and carnation) wastes through vermicomposting was evaluated. The study was done using wastes collected from two flower farms, Dugda Flora (Debre Zeit) and Ethiopian Magical Farm (Legedadi). The wastes were pre-composted by mixing with cow dung and arranged in piles with 80 cm height and 1.5m width under different treatments. The worms were introduced into the piles when the temperature and moisture of the piles was lowered to a level suitable for the worms. The physico-chemical variables of the vermicompost and size reduction of the wastes were evaluated at the beginning, middle and at the end of the experiment. It took 3 months for all rose wastes to be converted into vermicompost, while it took 6 months for carnation wastes. Size reduction ranged (from 49.6 to 87.5%), total nitrogen (TN) (1.43 to 2.5%), available phosphorus (P2O5) (1879 to 2600ppm), Available Potassium (AV.K) (73.3 to 105.5 cmol(+)/kg), carbon to nitrogen ratio (C:N) (12:1 to 28:1) for rose while TN ranged (1.6 to 2.3%), P2O5 (1867 to 2112 ppm), AV.K (73.3 to 103 cmol(+)/kg), C:N (14.4:1 to 25:1) for carnation during the same study period. There was no significant variation in terms of the quality of vermicompost produced by the worms and between the waste types; however, the process of vermicompost was delayed for carnation. There could be multifaceted reason for the delay but the recalcitrant nature of the plant seems to be the main reason. The overall results showed that all the three worms can be employed to manage both types of wastes.