New roller concepts for mechanical terminating cover crops in conservation agriculture in the southern United States

Authors: Kornecki, Ted; Price, Andrew; Raper, Randy; Arriaga, Francisco

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/23/2008
Publication Date: 6/23/2008
Citation: Kornecki, T.S., Price, A.J., Raper, R.L., Arriaga, F.J. 2008. New roller concepts for mechanical terminating cover crops in conservation agriculture in the southern United States. In: Proceedings of the International Conference on Agricultural Engineering, Hersonissos, Crete, Greece June 23-25, 2008. CDROM. Paper No. 1132659.

Interpretive Summary: Cover crops are a vital part of no till conservation system, but they must be managed appropriately not to create planting problems for producers. One technique to manage tall cover crops such as rye that produce large amounts of biomass is to roll down and crimp covers using rolling technology. Rollers/crimpers have been used by some U.S producers to manage cover crops but large vibrations limit the number of producers who are ready to adopt this technology. Field experiments were conducted in 2006 and 2007 with six different 1-section, 1.8 m wide roller designs: designs (1.8 m width) were tested at 3.2 and 6.4 km/hour: a straight-bar roller, curved-bar roller, a smooth roller without crimping bar, a smooth roller with an oscillating crimping bar and two different cam mechanisms, and two-stage roller. In 2006 and 2007, three weeks after rolling, all tested rollers effectively terminated rye from 95% to 98% which are recommended for planting a cash crop. In both years, rolled rye residue preserved much better soil volumetric moisture content compared to standing rye even under severe drought in 2007. At both speeds the original straight-bar roller design generated the highest vibration levels and exceeded comfort and health limits set by international standards. All other roller/crimper designs generated much less vibrations both on roller and tractor’s frames that are below health and comfort limits, thus improved comfort to the operator.

Technical Abstract: Rollers may provide a viable option to herbicides for terminating cover crops; however, excessive vibration generated by rollers and transferred to tractors hinders adoption of this technology in the US. To avoid excessive vibration, producers must limit their operational speed, which increases time and cost of rolling. The effect of speed on cover crop (rye, Secale cereale L.) termination rate, volumetric soil moisture content and vibration level was evaluated on different roller designs in 2006 and 2007. Six rollers single-section designs (1.8 m width) were tested at 3.2 and 6.4 km/hour: a straight-bar roller, curved-bar roller, a smooth roller without crimping bar, a smooth roller with an oscillating crimping bar and two different cam mechanisms, and two-stage roller. Comparisons were made with a standing rye. In 2006 and 2007, three weeks after rolling, all roller designs achieved from 95% to 98% rye termination rates which are recommended for planting a cash crop. In both years, soil volumetric moisture content was preserved much better with rolled rye compared to standing rye even under severe drought in 2007. At both operational speeds the original straight-bar roller design generated the highest vibration levels and exceeded comfort and health limits established by international standards. All other designs generated much less vibrations both on roller and tractor’s frames (below health and comfort limits) while maintaining or exceeding rye termination rates.