Using near infrared spectroscopy (NIRS) to identify the contribution of earthworms to soil macroaggregation in field conditions

•NIRS was used as a tool to identify origins of casts collected in the field.•Casts of each species were characterized by a specific NIR spectral signature.•74.5% of the total mass of casts could be identified in a forest site.•Best discrimination among casts was obtained for freshly produced casts.•Specific NIR wavelengths of casts were correlated with earthworm ecological groups.