Study of the effect of biochar application on soil fauna: avoidance assay with Eisenia fetida

Abstract

The use of by-products resulting from the pyrolysis process, such as biochar (BioC), has reveal increasing interest in maintaining edaphic environment, especially in the respective physicochemical properties, minimize the potential effects on biology conditions. This study aimed to evaluate the effect of applying different doses of a plant derived BioC on the behavior of Eisenia fetida, based on determining the percentage of escape or avoidance (% Evit) from a test soil (with biochar) compared to a control soil (without biochar), in order to estimate the potential risks to soil application, according to the required guidelines for this type of test (ISO 17512-1). The results showed a significant effect (p <0.05) of BioC application and dose on the behavior of the earthworms. In all treatments with BioC, avoidance of E. fetida was observed, with values ranging from 33 to 66%. Factors associated with an increase in soil water retention, pH, and electrical conductivity seem to explain the behaviour of earthworms in the BioC treatments, with more higher effects for 15 and 30 t/ha doses, where soil habitability limits, relative to 60% avoidance, were exceeded.