Effect of roller/crimper designs in terminating rye cover crop in small-scale conservation systems

Authors: Kornecki, Ted

Submitted to: International Agricultural Engineering Conference (IAEC)
Publication Type: Proceedings
Publication Acceptance Date: 7/6/2014
Publication Date: 7/6/2014
Citation: Kornecki, T.S. 2014. Effect of roller/crimper designs in terminating rye cover crop in small-scale conservation systems. In: Proceedings of the International Conference of Agricultural Engineering, July 6-10, 2014, Zurich, Switzerland.(Ref.: C0216 - www.eurageng.eu).

Interpretive Summary: Cover crops are an essential component of no-till agriculture and they improve soil quality, provide better weed control and conserve soil moisture. A common method to manage cover crops is using rolling/crimping technology. Small scale producers need rollers compatible with small tractors already used on farms. To address these needs, a field experiment was started in fall of 2011 in central Alabama to determine the effectiveness of three rollers/crimpers (one commercially available roller and two experimental prototypes) designed for walk-behind tractors. Rollers were operated at two speeds and from one to three rolling passes during springs of 2012 and 2013. In both years at two weeks after rolling, rolling/crimping three times generated increased termination rates compared to rolling/crimping once or twice. Overall, across both growing seasons, the rye termination rates generated by the experimental powered roller/crimper and the two stage roller/crimper were consistently higher compared to a commercially available chevron type, curved roller/crimper. In 2012, Soil water conservation was improved by rolled residue within one week after rolling, whereas in 2013, soil moisture for rolled rye was higher compared to standing rye one, two, and three weeks after rolling due to higher rye biomass that created better soil coverage.

Technical Abstract: In recent years, use of cover crops in no-till organic production systems has steadily increased. When cover crops are terminated at an appropriate growth stage, the unincorporated residue mulch protects the soil from erosion, runoff, soil compaction, and weed pressure, and conserves soil water. In the Southern United States, the recommended time to plant cash crops into residue cover is typically three weeks after terminating the cover crop, when the termination rate exceeds 90% and competition for resources is minimized between cover and cash crops. The expansion of fresh food production by local small vegetable farms must be associated with sustainable practices that include no-till systems with proper cover crop management. One method to properly manage and terminate cover crops is to apply rolling/crimping technology. Small scale producers need equipment compatible with small tractors already used on farms. To address these needs, a field experiment was initiated in fall of 2011 to determine the effectiveness of three rollers designed for walk-behind tractors. Results from two growing seasons are presented. In 2012, a powered roller generated rye termination rates of 91%, 92%, and 99%, compared to 88%, 94% and 100% obtained by a two-stage roller, at one, two, and three weeks after rolling. During the same evaluation period, a commercial curved roller generated lower termination rates of 75%, 88%, and 98%, compared to 38%, 53% and 80% for standing rye. Results indicated that two weeks after rolling, termination rates produced by the powered roller and the two-stage roller were high enough for cash crop planting into rye residue. One week after rolling, soil volumetric moisture content (VMC) for all rolled rye residue was higher (8.5%), compared to standing rye (5.4%) indicating better water conservation due to rolling. In 2013, rye termination rates by all rollers were lower compared to 2012 due to higher rye biomass in 2013 (9604 kg ha-1 vs. 8228 kg ha-1), higher moisture content (14% vs. 10%) and in 2013 rye was terminated at an earlier rye growth stage (early milk vs. soft dough). The powered roller generated average rye termination rates of 80%, 87%, and 87% which exceeded the 76%, 83%, and 82% obtained by the two-stage roller, at one, two, and three weeks after rolling. A commercially-available curved roller generated termination rates of 57%, 70%, and 73% which were lower than for the experimental rollers; during the same period, standing rye termination rates were 15%, 15%, and 45%. One, two and three weeks after rolling, VMC for standing rye was 6.7%, 13%, and 7.8%, compared to much higher VMC for all rolling treatments of 11.6%, 17%, and 13.7%, respectively, indicating that rolled residue conserved soil moisture by superior soil coverage, due to a mulch effect. Overall, in both growing seasons at two weeks after rolling, rolling/crimping three times generated increased termination rates compared to rolling/crimping once or twice. In 2012, increasing operating speed generated a higher termination rate one week after rolling (86% vs. 83%), whereas in 2013 higher termination rates were recorded one week (72% vs. 69%), and two weeks after rolling (82% vs. 78%).