Earthworms play a key role in soil processes, yet quantitative estimates of their burrowing activity under
field conditions remain scarce. Here, we present a method to quantify field earthworm burrowing rates
using repeated X-ray scanning of soil columns.
Perforated cylinders (10 cm diameter, 20 cm height) were fabricated using 3D printing and filled with soil.
Each cylinder contained 244 holes (11 mm diameter) to permit earthworm entry and exit. The cylinders
were buried for several months at a grassland site in Uppsala (Sweden) and periodically removed for X
ray scanning before being immediately reinstalled. In-situ sensors continuously recorded soil moisture and
temperature. Earthworm burrow networks were extracted from the X-ray images to quantify burrow
characteristics (volume, diameter and direction), assess burrow persistence, and calculate burrowing rates.
Burrows created by endogeic and anecic earthworms were further distinguished based on diameter.
Repeated removal and X-ray scanning of soil columns at 1-2 months intervals enabled quantification of
earthworm burrowing rates and assessment of burrow persistence. The estimated rates suggest that
complete burrowing of the topsoil would require approximately 40 years. The data further indicate that
anecic earthworm burrows accounted for about 40% of total burrow volume and that these burrows were
more persistent than burrows created by endogeic earthworms. Preliminary analyses suggest that soil
moisture exerted a stronger influence on burrowing rates than soil temperature. Overall, the approach
provides novel insights into the links between earthworm activity and soil structure dynamics.