Soil compaction negatively impacts soil functions, but its effects on soil microorganisms' resistance and resilience remain poorly understood. This study investigated the response of soil microbial diversity to a single compaction event and its subsequent evolution over four growing seasons under different agricultural management systems. While crop yields largely recovered after the initial decline, soil compaction persistently increased bulk density, and drastically reduced air permeability and gas diffusion. Compaction induced cropping system-dependent shifts in microbial communities, with limited resilience over the four seasons. Anaerobic prokaryotes and saprotrophic fungi increased in compacted soils, while aerobic prokaryotes and plant-associated fungi were negatively affected. Spatial variability across replicated blocks highlighted the influence of initial conditions on compaction effects. This research shows that soil compaction has long-lasting effects on soil properties and microorganisms, which may not always align with changes in crop yield.

Manon Longepierre, Franco Widmer, Thomas Keller, Peter Weisskopf, Tino Colombi, Johan Six, Martin Hartmann