In-Row Subsoilers that Reduce Soil Compaction and Residue Disturbance

Aboveground soil disruption prior to planting is avoided 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. For use in conservation tillage systems, belowground soil disruption should be maximized while aboveground disruption should be minimized. 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 tractor-mounted three-dimensional dynamometer was used to measure draft, vertical, and side forces in a Coastal Plain soil in Alabama. Three subsoiler systems were evaluated at different depths of operation: (i) Paratill™ bentleg shanks, (ii) Terramax™ bentleg shanks, and (iii) KMC straight shanks. A portable tillage profiler was used to measure both above- and belowground soil disruptions. Shallower subsoiling resulted in reduced subsoiling forces and reduced surface soil disturbance. The bentleg subsoilers provided maximum soil disruption and minimal surface disturbance and allowed surface residue to remain mostly undisturbed. Bentleg shanks provide optimum soil conditions for conservation systems by disrupting compacted soil profiles while leaving crop residues on the soil surface to intercept rainfall and prevent soil erosion.