A well-developed soil structure is a key attribute of a productive and functioning
soil. Evidence shows that subtle changes in the spatial arrangement and binding of
soil constituents impart large changes in soil mechanical and hydraulic properties
and associated ecological services. However, these features remain difficult to quantify
at spatial scales relevant for agricultural management. In this work, we propose
a pedophysical model to interpret macroscopic seismic properties in terms of soil
structure. The model captures subtle soil mechanical traits accounting for soil plastic
deformation due to compaction. In order to evaluate the model, we use data from
field monitoring at an experimental site that revealed elevated seismic velocities in
plots that were compacted 5 yr prior to our measurements. Our results show that
P-wave velocities carry a strong imprint of soil compaction and are well predicted
by the proposed model. The model infers contact areas between aggregates that are
nearly threefold larger for compacted than for non-compacted soils, indicating that
soils have not recovered from compaction. The study illustrates the potential of seismic
methods to identify chronic compaction at field scale.