Use of a mechanical roller-crimper as an alternative kill method for cover crops

Abstract

Abstract Cover crops have long been recognized as a beneficial component of many cropping systems; however, their use is still not commonplace. Usage may be increased by identifying more cost-effective and environment-friendly techniques for cover-crop management. This study was conducted to determine the effectiveness of using a mechanical roller-crimper as-an alternative method for killing cover crops. The study location was in east-central Alabama, using a split-split plot experimental design with four replications and 3 site-years during 1999–2000. Rye, wheat and black oat were evaluated in terms of ease of kill and optimum time of kill using a roller-crimper, two herbicides (paraquat and glyphosate) at their labeled rate, and two reduced chemical (half label rate) combinations of the same chemicals with the roller-crimper. Four Feekes' scale growth stages were used to determine optimum time of kill; 8.0 (flag leaf), 10.51 (anthesis), 10.54 (early milk) and 11.2 (soft dough). Plant growth stage was the main determining factor for effectiveness of the roller-crimper for killing the cover crops. At the flag leaf stage, the roller-crimper provided only 19% kill across all covers over the 3 site-years. After plants reached anthesis, the roller-crimper with half-rate herbicide combinations equaled the effectiveness of herbicides alone at their label rate, averaging 94% kill. By the soft dough growth stage, all kill methods were equally effective due to accelerating plant senescence (95% mean kill across kill methods). Use of the roller-crimper alone after anthesis can decrease costs by as much as $26.28 per ha, while providing a kill rate equivalent to that of herbicide treatment alone.