|Herrick, Jeffrey - Jeff|
Submitted to: Soil Quality Information Sheets
Publication Type: Government Publication
Publication Acceptance Date: 5/1/2001
Publication Date: 5/1/2001
Citation: HERRICK, J.E., TUGEL, A.J., SHAVER, P.L., PELLANT, M. RANGELAND SOIL QUALITY: COMPACTION. SOIL QUALITY INFORMATION SHEET. 2001. RANGELAND SHEET 4. Interpretive Summary: Interpretive summary not required for government publications.
Technical Abstract: Soil compaction occurs when moist or wet soil aggregates are pressed together and the pore space between them is reduced. Compaction changes soil structure, reduces the size and continuity of pores, and increases soil density (bulk density). Wheel traffic or pressure (weight per unit area) exerted on the soil surface by large animals, vehicles, and people can cause soil compaction. In areas of rangeland, compacted soil layers are generally at the soil surface or less than 6 inches below the surface, although they can be as deep as 2 feet under heavily used tracks and roads. Compaction is a problem when the increased soil density and the decreased pore space limit water infiltration, percolation, and storage; plant growth; or nutrient cycling. Compacted wheel tracks or trails can concentrate runoff that can create rills or gullies, especially on steep slopes. The following features may indicate a compacted soil layer: platy, blocky, dense, or massive appearance; significant resistance to penetration with a metal rod; high bulk density; and, restricted, flattened, turned, horizontal, or stubby plant roots. Because some soils that are not compacted exhibit these features, refer to a soil survey report for information about the inherent characteristics of the soil. Dry soils are much more resistant to compaction than moist or wet soils. Soils that are wet for long periods, such as those on north-facing slopes and those on the lower parts of the landscape, where they receive runoff, are susceptible to compaction for longer periods than other soils. Natural recovery is often slow, taking years to decades or more. To minimize compaction, minimize grazing, recreational use, and vehicular traffic when the soils are wet; use only designated trails or roads and reduce the number of trips; do not harvest hay when the soils are wet; maintain or increase the content of organic matter in the soil by improving the plant cover and plant production.