Submitted to: International Soil Conservation Organization Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: August 30, 1996
Publication Date: N/A
Technical Abstract: The average size of farm equipment continues to increase in the United States. Use of this heavy machinery for land cultivation often results in soil compaction with corresponding negative effects on soil functions. Harvest and associated transport equipment commonly have axle loads exceeding 10 Mg. An 8-row maize harvester and a large grain cart can have axle loads approaching 20 and 40 Mg, respectively. This paper reviews research conducted in Minnesota by several researchers over the past 20 years. Four passes of a wheel carrying an axle load of 18 Mg on a relatively wet soil caused increased penetrometer resistance to a depth of at least 45 cm, and increased bulk density to a depth of at least 60 cm. Smaller compactive loads, or the same load applied at a relatively dry soil water content caused less increase in bulk density, and the increase did not extend as deep. In the absence of further heavy axle loading, this subsoil compaction persisted for several years. When the growing season soil water status was either much wetter or much drier than normal, maize yield was reduced by up to 20%. Detailed soil data indicates that even if crop growth was not significantly affected, soil properties show long- lasting changes that may significantly affect movement of water and solutes through the soil profile. Pre-consolidation data may be a useful test to determine the limitations of a given soil to tolerate heavy wheel traffic of current farming operations, thus providing guidelines for use of heavy field equipment.