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Soil Compaction

Soil Compaction

by Steven P. Graber, Soil Scientist
Natural Resources Conservation Service
Dodge City, Kansas

Soil compaction occurs on nearly every farm in the United States, and the results are evident in crop growth. Recent research has shown that organic matter on the surface and within the soil is an important factor in reducing soil compaction. Low soil organic matter levels have been shown to make the soil more susceptible to soil compaction.

Organic residues on the surface have the ability to cushion the effects of soil compaction. It has the ability to be compressed but retain its shape and structure after the traffic has passed. This is unlike mineral soil aggregates which tend to compress under traffic. However, excessive traffic or tillage will break up organic matter, and accelerate its decomposition. Organic residues in the soil profile may be even more important than residues on the surface. This is because organic matter attaches to soil particles and helps to keep the particles from compacting.

Soil compaction has a biological component, and research has shown that a main cause of soil compaction is a lack of actively growing plants and active roots in the soil. Plant roots create voids and macro pores in the soil for air and water movement. Plant roots also provide the food source for soil microbes and fauna. Finally, organic matter is lighter and less dense, and when mixed with mineral soil material helps to reduce the density of the mineral soil material.

The alleviation of the compacted soil is not easy. Although subsoiling or chiseling can alleviate compaction immediately, the first pass by a single vehicle or implement may nullify the effort. The use of multiple strategies will be the best shot at solving the problem. Reducing tillage, controlling traffic, and increasing organic matter will all benefit the soil, improve soil quality, and increase crop production.

To learn more about soil compaction or get more information about natural resources conservation, please contact your local Natural Resources Conservation Service (NRCS) office or conservation district office located at your local county USDA Service Center. The office is located at your local U.S. Department of Agriculture (USDA) Service Center (listed in the telephone book under United States Government or on the internet at offices.usda.gov). More information is also available on the Kansas Web site at www.ks.nrcs.usda.gov. Follow us on Twitter @NRCS_Kansas. USDA is an equal opportunity provider and employer.

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