Physicochemical characterization of humic acid extracted from vermicomposting obtained by animal manure

Humic acid extracted from vermicomposting (VHA), originated by animal manure and treated with Eisenia foetida or Lumbricus rubellus, was chemically characterized concernings its elemental composition, cation exchange capacity, carboxylic and phenolic acidity, molar absorption by UV-Vis spectroscopy, and main functional groups by FTIR spectrometry. Vermicompost is the stabilized product from vermicomposting. The isolated VHA was compared to other humic acid samples extracted from peat and from different soils. VHA presented a high nitrogen content. Due to low cost, large amount of raw material, and favorable climatic condiditons, vermicomposting may become a good alternative to produce fertilizers in Brazil.