2008 Joint Annual Meeting (5-9 Oct. 2008): Tillage as a Mechanism for Enhancement of Clay Translocation and Argillic Horizon Development.

 Two columns, 30 cm x 60 cm x 9 cm, were constructed with a simple entisol model of a silty clayloam “A” horizon over a coarse sand “C” horizon. Over the course of a year, the columns were subjected to identical moisture regimes with 2.5 cm of water at a time being ponded on the surface and allowed to percolate through the column. One column was “plowed” 152 times, prior to introduction of water, the other was not. The columns were then deconstructed and examined. Slides were made of sampling points within the columns and examined using both optical and scanning electron microscopes. The “plowed” column appeared to exhibit significantly higher clay translocation, both in mass and depth of translocation, than the “unplowed” column. The “plowed” column appeared to have obvious clay translocation to a depth of 8 cm as opposed to 4.2 cm for the “unplowed” and exhibited distinct clay coatings on sand grains and clay bridging between grains. This indicates that agricultural practices may contribute significantly to the formation and thickening of argillic horizons.