Cover Crop Termination with A Front-Mounted Roller in No-till Organic Corn Production.

The use of cover crops is a common sustainable agricultural practice in no-till and organic systems. However, these systems are often seen as mutually exclusive based upon cover crop termination and weed control. No-till relies on herbicides, while organic farming mainly uses tillage.

 We evaluated a front-mounted roller-crimper for termination of annual winter cover crops common in the southeastern USA. Specifically, we evaluated the effectiveness of the roller crimper to kill an oat (Avena sativa L.) and crimson clover (Trifolium incarnatum L.) cover crop at different operating speeds, applied downward pressure levels, and number of passes with the roller. 

 At the time of planting corn, the rolled cover crop showed a significantly decrease in chlorophyll index from 155 to 120 in the order of passes one>two>three. Cover crop digital analysis indicated a decrease from 73% for one pass to 61% green for two passes. Corn emergence increased from 15,209 plants/acre for one pass to 17,819 plants/acre for two passes. Higher speed increased emergence from 16,344 plants/acre to 17,809 plants/acre. The effect of applied pressure showed a decrease of the chlorophyll index only, from 146 to 130. Pressure also had an interactive effect with the number of passes on weed population 5 weeks after planting. There were no significant differences in weed density after 7 weeks, average 37,330 plants/acre, or in final corn stand or yield, as expected without N application. Overall, all treatments gave good results in terms of percent soil cover and weed suppresion.

These results suggest that the front-mounted roller can effectively be used kill annual winter cover crops and control weeds in the southeastern USA with little benefit from higher speed or pressure applied, and with three passes being redundant.