Earthworms contribute to soil functioning by burrowing through soil, but quantitative knowledge of their burrowing
activities and how environmental factors influence it under field conditions is still limited. The objectives
of this study were to test a method for quantification of the temporal dynamics of in-situ earthworm burrowing
rates, and to investigate links between variations in burrowing rates and soil moisture and temperature. Specially
designed perforated cylinders repacked with soil were installed in an arable field with a known earthworm
community in Uppsala, Sweden, and repeatedly removed, X-ray scanned, and re-installed, during May-October
2023. Earthworm burrow volumes and characteristics of burrow networks were derived from the X-ray images.
Burrows were classified into burrows likely originating from endogeic earthworms (burrow diameter ≤ 4 mm)
and anecic earthworms (> 4 mm). We tested two methodological approaches, using either new repacked soil
after each scan or re-installing the same soil cylinder. We also employed two soil moisture treatments (with and
without rainout shelters). In-situ soil moisture and temperature were monitored using sensors. The results
showed that burrowing rates in newly repacked soils were higher than in the soil columns with the same soil.
Depending on treatment and the time of the year, mean burrowing rates varied between 0.05 and 0.64 cm3
day 1. On average, we estimated that topsoil turnover rate by earthworm burrowing is about 21–42 years in this
field where the earthworm abundance was 81 individuals per m2. The data from the “same soil” treatment indicates
that a steady state in earthworm burrow volume was achieved after five months, indicated by the balance
between burrow creation and disappearance. In our study, soil moisture appeared to be a more important driver
for earthworm burrowing than soil temperature. We show that about 40% of the earthworm burrow volume was
classified as anecic earthworm burrows in the topsoil. We conclude that the proposed method using perforated
cylinders with repeated scans is suitable for seasonal monitoring and to quantify earthworm burrowing rates
under field conditions.