Species specifity of lumbricidae in bioconversion of organic substrates

Abstract

The article is devoted to decomposers of family Lumbricidae. The purpose of the work was to study specificity of bioconversion of organic substrates by different species of Lumbricidae. The objectives included vermiculture in organic substrates followed by an assessment of the chemical composition of the humus obtained, an assessment of its nutritional value and the content of heavy metals. It was shown that the chemical composition of the biohumus and its nutritional value were determined by decomposer species. The nutritional value of the biohumus obtained with the activity of natural species E. fetida and L. rubellus were not inferior to the biohumus obtained with the activity of industrial hybrid E.f. andrei. Transition of biogenic elements of the substrate into accessible forms for plants was caused by intestinal microbiota of Lumbricidae. The conversion quality of each organic substrate was determined by ecological niche taken by tested species of Lumbricidae. Lumbricides from different ecological niches converted the same substrate with different performance. L. rubellus, in accordance with their nutritional adaptation, began decomposion processes at later stages of biotic cycle, in comparison with compost worms E. fetida and E.f. andrei, therefore, the vermitransformation rate of the original substrates provided by this species was the lowest. All tested species were characterized by a threefold decrease in the level of heavy metals in vermicompost due to the binding by organic compounds produced by intestinal microbiota with a transition into immobile forms.