Submitted to: Applied Engineering in Agriculture
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/20/2005
Publication Date: 3/20/2005
Citation: Raper, R.L. 2005. Force requirements and soil disruption of straight and bentleg subsoilers for conservation tillage systems. Applied Engineering in Agriculture. 21(5):787-794. Interpretive Summary: In-row subsoiling prior to planting has become a valuable conservation tillage practice for producers to combat soil compaction and leave large amounts of crop residue in place. Many different tillage shanks are available for producers to choose for in-row subsoiling. However, some are better at minimally disrupting the soil surface and leaving crop residue in place while others are better at disrupting the soil profile and removing soil compaction. This experiment was conducted to determine the best shanks for conservation tillage systems based on the following criteria: minimally disturbing soil on the soil surface, maximally disturbing the soil profile, and requiring minimal amounts of tillage energy. Two shanks from different manufacturers that are bent to one side were found to excel at all of these criteria. Producers who need to reduce soil compaction problems in their conservation tillage systems could use either of these shanks and receive the maximum benefits for the crop rooting systems while protecting the environment.
Technical Abstract: Aboveground soil disruption prior to planting is not wanted in conservation tillage systems due to the need to keep plant residue in place. However, belowground disruption is necessary in many Southeastern U.S. soils to ameliorate soil compaction problems. To assist in choosing the best shank for strip-tillage systems which accomplish both objectives, comparisons were made between several shanks commonly used for conservation tillage systems to provide in-row subsoiling prior to planting. A three-dimensional dynamometer was used to measure draft, vertical, and side forces for experiments conducted in the soil bins of the USDA-ARS National Soil Dynamics Laboratory in Auburn, AL. A portable tillage profiler was used to measure both above- and belowground soil disruption. For use in conservation tillage systems, belowground soil disruption should be maximized while aboveground disruption should be minimized. Two parameters, spoil resistance index and trench specific resistance, were defined in the paper to consider the effect of draft force, aboveground soil disruption and belowground soil disruption. The two best shanks for conservation tillage systems based on these selection criteria are the BBP shank and the BWT shank, which are both bentleg shanks from different manufacturers.