Electronic Field Guide » Restoration & Goals » Soil Compaction
Prepared by Patrick Drohan (Crop and Soil Sciences)
Soil compaction can occur at the surface and/or subsurface, and is one of the most common landscape/soil problems encountered across all infrastructure elements. For example, seismic investigations may result in soil compaction in wet areas. Certainly pad and pipeline development will result in compaction.
Soil compaction occurs when a weight (tire, piece of equipment, container, etc.) compresses voids within the soil, resulting in rearrangement of soil inorganic and organic material. This causes less void space for air or moisture. If surface compaction occurs, the movement of water into the soil surface (infiltration) can decrease. Compaction of a wet surface with a sheer force applied to the soil can result in smearing of the surface. This will seal the surface and make it nearly impermeable to water movement; ponding then occurs, and if ponding is substantial enough, then overland flow will result. Excess overland flow can lead to soil erosion and sediment build-up in nearby water bodies.
Checking periodically for sediment build-up in silt fences or silt socks can help prevent failures of these erosion control devices, and minimize loss of valuable soil and associated organic matter and nutrients.
Visible and physical signs of a potential compaction problem can include standing water, stunted plant growth, discolored leaf tissues, and/ or a soil surface that feels unusually hard when walked upon. If you suspect that compaction is a problem, there are several direct and indirect tests one can conduct on the disturbed site and on a native, similar undisturbed soil for comparison. See Repairing Soil Compaction.