The effects of the invasive species Eisenia tracta and Aporrectodea caliginosa and the native species Eisenia nordenskioldi pallida, individually and in combination, on changes in the total organic matter content of Gleyic Chernozem were compared in a one-year experiment. Soil organic matter was determined by photometric oxidation with potassium dichromate in sulfuric acid. The invasive species A. caliginosa had the greatest impact on the soil organic matter content, especially in combination with other species. The obtained results can be used to predict changes in soil organic matter under the influence of earthworms.
Unru et al. (Mon,) studied this question.