PERSISTENCE OF SOIL STRUCTURAL MODIFICATIONS ALONG A HISTORIC WAGON TRAIL

Authors: Sharratt, Brenton; Voorhees, Ward; MCINTOSH, GORDON - UNIVERSITY OF MINNESOTA

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/17/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Modern farm machinery can cause compaction to soils which could hamper soil productivity in the future. We are uncertain how long it takes to fully restore the physical attributes of the soil once the soil is compacted. However, past studies have shown that soil properties may remain altered for at least one decade after compaction. We documented the current state of soil physical properties along a historic wagon trail that hasn't been utilized in the past 110 years. Our findings suggest that soil pore size, soil density, and soil strength are not yet fully restored to their original condition despite the natural forces that affect change in soils. Thus, to preserve the integrity and productivity of our soils for future generations, soil compaction must be curtailed on susceptible soils. These studies can be used by scientists and farm equipment manufacturers to develop machinery that minimize soil compaction. .In addition, this report would be beneficial to extension personnel to disseminate information concerning trafficking wet soils as well as using confined wheel traffic.

Technical Abstract: Tractors and implements driven over soils can cause compaction or plastic deformation, both of which cause changes in soil structure that effect the long-term productivity of fine-textured soils. Swedish experiments related to amelioration of compaction from soil processes such as wetting and drying and freezing and thawing suggests that subsoil compaction can persist for a decade. A paucity of information exists, however, on the persistence of soil structural modifications caused by vehicular traffic beyond a decade. Wagon wheel ruts are still evident along pioneer trails that traversed the continental United States in the 1800's, suggesting that soil properties remain modified after a century. One such trail, the Wadsworth Trail that traversed western Minnesota from 1864 to 1871, was the focus of this investigation. We examined soil water content, thermal conductivity, penetration resistance, water infiltration, and air permeability across three transects of the Trail. Soil strength was greater within the area trafficked by wagon wheels and animals as indicated by higher penetration resistance compared to the non-trafficked area. Soil pore structure and continuity also appeared to differ between the non-tracked and wheel-tracked areas of the Trail as indicated by differences in soil water content, water infiltration, and air permeability. Indeed, complete amelioration of physical properties caused by compaction or plastic deformation from wagon wheel and animal traffic or by erosion and deposition was not evident after 110 years. This information suggests that for a sustainable agricultural system, vehicular traffic should be confined to wheel lanes and curtailed across wet soils.