Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 4, 2010
Publication Date: N/A
Technical Abstract: While plow pans (a thin layer of compacted soil at the bottom of the normal tillage depth) in the Central and Southern US tend to be genetic in origin, they were believed to be wheel-induced in the upper Midwest by running the rear tractor wheel in the plow furrow. But it was also believed that annual freeze-thaw cycles would alleviate this compacted layer. However, anecdotal observations questioned the validity of this belief. Thus in the mid 1950s, Dr. George Blake in the Soils Department at the University of Minnesota conducted a field experiment on plow pan soil compaction at the Southwest Minnesota Experiment Station in Lamberton, Minnesota. Dr. Ray Allmaras did some follow up research on these field experiments in the early 1960s that provided solid evidence for persistence of soil compaction in the upper Midwest. Dr. Allmaras with cooperation from Dr. Wally Nelson, Superintendent of the Southwest Experiment Station, then developed a plan for an expanded field study on wheel-induced soil compaction. However, Dr. Allmaras was transferred to Pendleton, Oregon, before his plan could be implemented. I then assumed responsibility for this research. Results clearly showed that wheel-induced soil compaction significantly affected root growth patterns in a way that had practical agronomic impacts. This lead to an international study on the effect of heavy farm machinery on deeper subsoil compaction. This paper will review Dr. Allmaras' role in establishing some early basis for soil compaction research and the subsequent research conducted on an international scale by the author of this paper.