What does compaction look like?
On the soil surface, compaction is likely where there is “cloddiness” with soil resisting breakup by rain or tillage, deep ruts, ponding or pushed and deformed soil from tyres. In the soil profile, dense impenetrable layers are found, commonly with horizontal, plate-like structure (i.e. hard-pan). Compaction is more likely in the subsoil. Dense subsoil can also have a “massive” (or featureless) appearance, a puggy feeling with peds breaking with force or tearing rather than along normal fracture lines. Associated symptoms include poor establishment adjacent to the wheel tracks, water ponding in tracks and headlands, distorted crop root systems (“right angle” disease), crop lodging and “thirsty” crops due to shallow rooting. Crops with thick taproots (e.g. safflower, lupins, canola) have a better ability to penetrate these compacted layers than those with fibrous roots (wheat, barley).
