New roller crimper concepts formechanical termination of cover cropsin conservation agriculture

Rollers crimpers have been used in conservation agriculture to terminate cover crops; however, excessive vibrationgenerated by the original straight-bar roller design has delayed adoption of this technology in the United States. To avoidexcessive vibration, producers generally reduce operating speeds that increase the time needed to perform the fieldoperation. The objectives of this research were to identify roller crimper designs that terminated rye cover cropsconsistently, resulted in soil moisture conservation after use, and minimized vibrations when operated in the field. Sixdifferent roller types were developed and tested at 3.2 and 6.4 km h - 1 in Alabama field experiments during the 2006, 2007and 2008 growing seasons. All roller types were used alone and one also in combination with glyphosate. Rye mortalitieswere evaluated 1, 2 and 3 weeks after rolling and compared with the check (non-rolled standing rye). Soil volumetricmoisture content (VMC) was measured at the day of rolling, and then at 1, 2 and 3 weeks after rolling. Vibration wasmeasured on the rollers’ and tractor’s frames during operation. Mortality for rolled rye 2 weeks after rolling was at least98% compared with 96% for the check in 2006, 93% for rolling compared with 75% for the check in 2007, and 94% forrolling compared with 60% for the check in 2008 (P < 0.10). There were no consistent differences in rye mortality acrossroller types (without glyphosate) and speeds. VMC for soil in non-rolled rye plots was consistently lower than in rolled ryeplots, averaging 3% compared with 7% 2 weeks after rolling in 2006, and 4% compared with 8% in 2008. During 2007,VMC was affected by severe drought conditions, and differences between roller treatments were detected but minor. Thestraight-bar roller generated the highest vibration on the tractor’s frame at 6.4 km h - 1 (0.71ms - 2, RMS), which exceededInternational Standards (International Standard Office (ISO)). At 6.4 km h - 1, new roller designs generated significantlylower acceleration levels from 0.12 to 0.32ms - 2 on the tractor’s frame and were below detrimental effects on health ‘healthlimits’ classified by ISO. Overall, 2 weeks after rolling, all roller designs effectively terminated rye above 90%, which is therecommended termination level of rye to plant a cash crop into residue mat, while protecting soil surface from water lossNew roller designs generate less vibration than the original design and can be used safely at higher operating speeds