Mycotoxin contamination and its regulation by the earthworm species Lumbricus terrestris in presence of other soil fauna in an agroecosystem
Background and aims In 2011 and 2013, mesocosm-studies were conducted in the field to assess the degradation performance of soil fauna (earthworms: Lumbricus terrestris, collembolans: Folsomia candida and nematodes: Aphelenchoides saprophilus) on mycotoxin-contaminated crop residues. The aim of the study was to investigate the potential of anecic earthworms in the regulation of the mycotoxin deoxynivalenol (DON) and whether the degradation capacity is influenced by the presence of collembolans and nematodes. Methods After 4 and 8 weeks, DON concentrations in residual straw and in soil samples of all faunal treatments (containing earthworms, collembolans and nematodes in different combination) and the non-faunal control treatments were determined using an ELISA-method. Results After 4 weeks, the DON concentration in straw decreased in all treatments: faunal treatments 2011: 97–99 %; 2013: 78–94 %; non faunal treatments 2011: 88 %; 2013: 68 %. After 8 weeks a further decline of DON concentrations was measured in all faunal treatments (2011: 58–91 %; 2013: 50–86 %). DON concentration of the non-faunal treatments increased during the final four weeks. In soil the DON concentration was below quantification limits (<0.037 mg kg−1). Conclusion This study revealed L. terrestris as the driver of the degradation process. The presence of collembolans and nematodes did not affect its degradation capacity. Earthworms contribute to a sustainable control of mycotoxins in wheat straw, thus reducing the risk of environmental pollution as an ecosystem service.
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