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Soil Productivity as Affected by Mechanical Influence
L.G. Wells, L. Murdock, T. Stombaugh
Department of Biosystems and Agricultural Engineering
Machinery traffic can cause adverse compaction of cropland that results in reduced yield. The purpose of this research is to develop a means of preventing adverse compaction of soil during reconstruction after mining and to determine an optimum procedure to identify and ameliorate adverse soil compaction in conventional cropland.
2009 Project Description
Field measurements were collected during April-May 2009 to evaluate the utility of the soil coulterometer which has been developed as a component of this project. Soil coulterometer measurements were recorded along separate transects across a field at depths of 4, 8 and 12 in. Soil cone index and soil bulk density were measured at 75 discrete locations along each transect at the corresponding depth. Correspondence of coulterometer measurements to these locations was accomplished by comparing DGPS coordinates. Correlation between coulterometer indices and both soil cone index and dry bulk density was poor. The experiments will be repeated in 2010 using more precise correspondence of measurement locations. A preliminary evaluation of the soil coulterometer as a predictor of soil bulk density and cone index was published in Applied Engineering in Agriculture. Corn yield was measured on plots reconstructed by a mechanical soil replacement system in 2009. A randomized block design was utilized in which 4 reconstruction treatments (separating or combined A & B horizons, with and without 22 tons/ac organic matter) were applied in triplicate. The average yield was 233 bu/ac and the range was 192 to 265 bu/ac. These measurements will be repeated in 2010 and 2011.
The development of the soil coulterometer could be instrumental in the implementation of site specific remedial deep tillage. This system is intended as a cost-effective means of locating adverse soil compaction in fields so that site-specific remedial tillage can be applied. This approach offers substantial potential reducing energy use and improving production efficiency and profitability. The successful demonstration of the mechanical system for reconstructing cropland offers the potential of returning most or all cropland subjected to surface mining, or similar massive disturbance, to original productive capacity. The impact would be substantial in maintaining U.S. agricultural productivity.
Tom Mueller's research group has been testing the Veris NIRS field spectrometer that was purchased with Hatch funding. They have conducted extensive testing in the laboratory and field. In the laboratory, they tested the instrument with the North American Proficiency Testing (NAPT) test soils. They found that they could predict carbon with the NAPT samples with an r2 value of 0.68 using simple linear regression (these results were based on a leave-a-subset-out validation analysis). They also are testing the spectrometer in probe and shank mode but these analyses have not yet been finalized. Additionally, they are comparing the Veris spectrometer with a research grade laboratory spectrometer.
Pitla, S.K., L.G. Wells and S.A. Shearer. 2009. Integration of an extended octagonal ring transducer and soil coulterometer for identifying soil compaction. Applied Engineering in Agriculture 25(5): 647-652.