Effects of Different Rollers and Rye Termination Methods on Soil Moisture and Cotton Production in a No-Till System

In the southern U.S., rollers/crimpers are used to terminate cover crops approximately 3 weeks before planting cotton when the cover crop reaches > 90% termination. When spring is wet or cold, the 3-week period is reduced to keep recommended planting dates. A 3-year experiment was initiated in Alabama to determine the effectiveness of a 4-stage roller/crimper in increasing termination rates for cereal rye compared to 2-stage and spiral rollers/crimpers in rolling 1, 2, and 3 times over rye along with a single-pass smooth roller with glyphosate application. Effects of rye termination at 7, 14, and 21 days after rolling were assessed as were the effects on soil water conservation, cotton population, and yield. Seven days after rolling, the 4-stage, 2-stage, and spiral rollers rolling 3 times generated 96, 92, and 81% termination, respectively. Termination with the smooth roller with glyphosate was 94% and the control (no rolling) was 37%. At 14 days, termination among rollers was 91 to 98% and at 21 days no differences were found among rollers (99-100%). The 4-stage roller 3 times had the highest average soil volumetric water content (VWC) of 16.1%, whereas the spiral roller 1 time had the lowest (13.6%). Rolled rye had higher VWC content averaging 14.7% (12-cm surface layer) compared to the control (12.7%). Rolling treatments affected cotton emergence only in 2015; cotton population and yield were not affected. Seven days after rolling, the 4-stage and 2-stage roller/crimpers exceeded 90% rye termination making earlier cotton planting possible if required by climatic conditions.