Quality of Vermicompost Obtained from Residues of Forestry and Livestock

The forestry-livestock waste materials represent a serious ecological problem if they are not handled properly in agricultural activities. Vermicomposting is a biotechnological process with potential to transform such materials into products that can be safely used as soil enhancers. The objective of this study was to evaluate the nutritional characteristics of organic fertilizers obtained from forestry-livestock organic waste materials when they are processed through vermicomposting using “Red Californian Earthworm” (Eisenia fetida). A completely randomized experimental design with four treatments and eight replicates was performed. Treatments (mixtures) included: leaf litter + sawdust (LS), bovine manure + sawdust (BS), rabbit manure + sawdust (RS), and ovine manure + sawdust (OS). Total nitrogen, pH, carbon/nitrogen ratio, organic carbon and nitrates from vermicompost samples were measured and statistically analyzed using SAS v8.2. At the end of the study, all mixtures showed similar characteristics according to the analyzed variables. Carbon/nitrogen ratios decreased in three mixtures to values considered as within the vermicompost maturity stage. Contents of nitrates and total nitrogen were increased. Final pH showed statistical difference among all mixtures. Results indicate that vermicomposting is a viable process for recycling forestry-livestock organic waste materials since it improves their chemical and nutritional characteristics.