Research Accomplishment Reports 2007

Soil Productivity as Affected by Mechanical Influence

L.G. Wells, L. Murdock, T. Stombaugh
Department of Biosystems and Agricultural Engineering

 

Project Description

An experimental device for assessing soil compaction was designed, fabricated and tested. A 32 in. diameter straight coulter was mounted on a two-directional force gauge to measure horizontal and vertical soil resistance. The coulter assembly was mounted on a tractor 3-point hitch and was oscillated vertically by the action of a hydraulic cylinder such that coulter depth continuously varied between 2 in. and 14 in. as the tractor moved forward. Vertical and horizintal soil resistance, coulter depth and GPS coordinates were recorded continously in order to map soil compaction in a field. Measurements of vertical and horizontal coulter soil resistance were compared to conventional soil cone penetrometer and soil bulk density measurements. Excellent correlation between both vertical and horizontal coulter resistance and soil bulk density was determined. Correlation between coutler resistance and soil cone index was less than expected, perhaps owing to inaccurate recording of penetrometer depth. These results were presented at the 2007 International Meeting of the American Society of Agricultural and Biological Engineers.

A mechanical system for reconstructing severely disturbed soil (U.S. patent no. 6,056,066) was modified and tested. Approximately 1.5 ac of silt loam cropland was excavated to an approximate depth of 3 ft at a site on a University of Kentucky research farm. The experimental system was used to then reconstruct the soil while completely avoiding mechanical traffic and resultant compaction. The site was reconstructed using four treatments replicated three times. The treatments were: A- and B-horizons separated, no organic matter added; A- and B-horizons mixed, no organic matter added; A- and B-horizons separated, 22 tons/ac organic matter added; and, A- and B-horizons mixed, 22 tons/ac organic matter added. The mechanical system reconstructed soil at a maximum rate of approximately 850 cu.yds. per hour. These reults were reported at the 2007 Annual Meeting of the American Society of Mining and Reclamation.

Impact

The 'coulterometer' will be submitted for potential patenting in 2008. If subsequent evaluation proves successful, the device could be used to inexpensively map potential adverse compaction in fields and provide the basis for site-specific remedial deep tillage.

A proposal was submitted to the U.S. Office of Surface Mining to evaluate the mechanical soil reconstruction system on a surface coal mine operated by Peabody Energy. The proposed project would result in a side-by-side comparison of the system with the current best method used by Peabody Energy. Soil reconstruction rate and resulting soil physical properties would be intensively mopnitoried and compared during 2008. The ultimate goal of the project would be to establish the system as a superior method of soil reconstruction which can re-establish crop production potential in prime farmland and other agricultural soils.

Publications

Pitla, S.K., L.G. Wells and S.A. Shearer. 2007. Identifying soil compaction using an extended ring transducer and soil coulterometer. Amer. Soc. Agr. and Biol. Engineers paper no. 071005, St. Joseph, MI.

Bodapati. V.S. and L.G. Wells. 2007. Evaluation of a mechanical system for reconstructing soil without traffic compaction. Procs. of the 2007 Annual Meeting of the Amer. Soc. for Mining and Reclamation, Gillette, WY.