Identification of Soybean Husk and Cow Manure Metabolites after Vermicomposting

Abstract

Soybean husk and cow manure are organic wastes that can be used as raw materials for making organic fertilizers through vermicomposting technique. To explore the potential, it was necessary to identify the vermicompost metabolites produced. Gas Chromatography-Mass Spectroscopy (GC-MS), a powerful tool, was used to identify metabolites that characterize vermicompost. The purpose of this study was to identify vermicompost metabolites derived from different proportions of soybean husk and cow manure. Information obtained can guide alternative soybean husk and cow manure use, especially as raw materials for organic vermicompost fertilizer. The materials used in this study consisted of soybean husk, cow manure and lumbricus rubellus earthworms. This vermicomposting study was conducted using a Randomized Complete Block Design (RCBD) with five treatments and five replicates. The treatment details are: V1 = soybean husk (100%); V2 = cow manure (100%), V3 = soybean husk: cow manure (50%: 50%); V4 = soybean husk: cow manure (75%: 25%) and V5 = soybean husk: cow manure (25%: 75%). Metabolites were analyzed using GC-MS and the Least Significant Difference (LSD) test. Based on GC-MS analyses of all treatments (V1-V5), metabolites were identified consist of sugar compounds, amino acid compounds, organic acids, vitamins, and hormones. Consistent relationships between chromatograms of treatment V1-V5 were directly proportional to the LSD test results; treatment V5 consistently yielded the highest total area under the curve