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item Raper, Randy

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/29/2004
Publication Date: 10/11/2004
Citation: Raper, R.L. 2004. Selecting subsoilers to reduce soil compaction and minimize residue burial. Meeting Proceedings. In: Proceedings of Session IV of the 2004 CIGR International Conference, October 11-14, 2004, Beijing, China. p. 135-143.

Interpretive Summary: Selecting the best implement for eliminating compacted soil layers and producing optimum crop yields is mostly driven by implement cost. However, implements for deep tillage vary in their ability to maintain crop residues on the soil surface which is extremely important for conservation tillage systems. A field experiment was conducted which compared several deep tillage implements which are commonly used for soil compaction disruption. Results from this experiment showed that bentleg shanks maintained the highest amount of crop residue on the soil surface while not requiring additional force to disrupt compacted soil profiles. Producers who must conduct deep tillage to manage soil compaction can use these bentleg shanks with confidence that they are able to maintain maximum amounts of crop residue on the soil surface.

Technical Abstract: 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 Coastal Plains soils in Alabama, USA. Three subsoiler systems were evaluated: (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. The trench specific resistance was used to consider the combined effect of draft force and belowground soil disruption. The amount of residue remaining on the soil surface after subsoiling was also measured. 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.