Submitted to: Applied Engineering in Agriculture
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/1/2009
Publication Date: 1/13/2010
Citation: Kornecki, T.S., Price, A.J., Raper, R.L., Bergtold, J.S. 2010. Effectiveness of different herbicide applicators mounted on a roller/crimper for accelerated rye cover crop termination. Applied Engineering in Agriculture. 25:819-826. Interpretive Summary: Two different methods of glyphosate application (nozzle and herbicide saturated felt systems) combined with the rolling/crimping of rye were compared during three growing seasons (2006-2008). One week after the rolling/crimping operation combined with different glyphosate applications provided between 94 to 100% of rye termination rates. The nozzle spray system controlled by high speed solenoid valves provided much better control in discharging the herbicide to the rolled residue as compared with the felt strip attached to the crimping bar. The felt-strip system generated kill rates comparable to the nozzle system (96-98%). However, it required the use of more herbicide due to the time required to saturate the strip before starting the experiment and dripping herbicide after the operation was completed. In addition, when the soil surface was uneven, some plants may not be contacted sufficiently to terminate their growth. Rolling/crimping alone and with glyphosate conserved more than 3% of the soil moisture as compared to non-rolled rye. As observed in 2008, when rye biomass was lower, the rate of herbicide application can be reduced (i.e., use every 4th crimp and not every other crimp or continuous spray) since spraying every 4th crimp provided 98% termination. Spraying glyphosate every 4th crimp provided high kill rates (96-98%) one week after rolling. Substantially reduced amounts of herbicide (up to 87%) were used by this process which could save producers up to $36.87/ha.
Technical Abstract: Under ideal weather conditions and weed free, a cash crop can be planted 3 weeks after rolling a mature cereal rye winter cover crop without using herbicides. However, cloudy and wet weather can delay the rolling and/or desiccation of rye thereby delaying cash crop planting which can reduce yield. One effective way to shorten the time between rolling and planting is to apply herbicide using a sprayer while rolling. However, a continuous spray may not be required if a roller/crimper is used due to the additive effect of the roller. Two different methods of applying glyphosate (RoundupTM) to rolled rye were compared. First, a felt strip saturated with herbicide was attached to the roller’s crimping bar and provided glyphosate application with every crimp. The second method consisted of a boom (five nozzles controlled by solenoid valves) mounted on the roller applying a spray either continuously, every 2nd crimp, or every 4th crimp. Results showed that 7 days after rolling, the highest rye termination rates were observed for continuous spray (100%) and for spray every 4th crimp (98%). The glyphosate saturated felt strip and 2nd crimp also resulted in adequate termination. For the roller/crimper alone and non-treated rye (standing rye), termination rates were 92% and 70%, respectively. Since spraying glyphosate every 4th crimp provided a 98% termination rate one week after rolling, it may be feasible to use this method to facilitate the cash crop to be planted in a timely fashion while reducing input costs. Economic savings of $12.63 to $36.87 ha-1 may be attained by incorporating herbicide applications with rolling activities. One and two weeks after rolling, volumetric soil moisture content for all rolled rye/chemical treatments were significantly higher compared to standing rye.