EFFECTIVENESS OF DIFFERENT ROLLER DESIGNS ON MANAGIN G RYE AS A COVER CROP IN

Rollers may provide a viable alternative to herbicides for terminating cover crops, however, excessive vibration generated and transferred to the tractor hinders adoption of this technology in the U.S. To avoid excessive vibration, producers must limit their operational speed, which increases time and cost of rolling. The effect of speed on rye (Secale cereale L.) termination rate, vibrations and cotton yield was tested for two roller designs during the 2004-2005 growing season. A triple-section roller (4.1 m wide) with long straight bars (straight bar roller) and a smooth roller with an oscillating crimping bar (smooth roller/crimper) were evaluated at speeds of 3.2 and 6.4 km h-1. Cover termination and cotton yield were recorded. In 2004, higher rye termination rates resulted from the straight bar roller (96%) in comparison with the smooth roller/crimper (94%). Three weeks after rolling, both rollers had effectively terminated rye without use of herbicides. The smooth roller/crimper transferred lower vibration levels to the tractor’s frame than the straight bar roller at both speeds. No differences in cotton yield were found between roller types, speeds and chemical treatment (glyphosate) except for lower cotton yield recorded for the smooth roller/crimper at the speed of 3.2 km h-1. Cotton yield in 2004 was decreased by hurricane Ivan and these results might not be representative for normal weather conditions. Under typical weather conditions in 2005, higher cotton yield resulted following straight bar roller and glyphosate application, and might be associated with higher soil moisture availability due to faster termination of rye