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The ever-increasing weight of agricultural machines exacerbates the risk of subsoil compaction, a condition believed to be persistent and difficult to alleviate by soil tillage and natural loosening processes. However, experimental data on the persistency of subsoil compaction effects on soil pore functioning are scarce. This study evaluated and quantified persistent effects of subsoil compaction on soil pore structure and gas transport processes using intact cores taken at 0.3, 0.5, 0.7 and 0.9m depth from a loamy soil in a compaction experiment in southern Sweden (Brahmehem Farm). The treatments included four repeated wheelings with ∼10Mg wheel loads. Water retention characteristics (WRC), air permeability (k_a) and gas diffusivity (D_s/D_o) were measured. A dual-porosity model fitted the WRC well, and there was a reduction in the volume of macropores >30μm in compacted compared with control soil for all soil …