THE INFLUENCE OF A HAIRY VETCH (VICIA-VILLOSA) COVER CROP ON WEED-CONTROL AND CORN (ZEA-MAYS) GROWTH AND YIELD

Influences of a hairy vetch cover crop and residual herbicides were ex amined in field corn in 1991 and 1992. Hairy vetch was seeded in mid-A ugust and killed the following May with tillage, mowing, or glyphosate plus 2,4-D (no-till). These cover crop management systems were compar ed with a no-cover treatment. Residual herbicides including atrazine p lus metolachlor applied PRE at three rates and nicosulfuron plus thife nsulfuron applied POST at a single rate were compared within cover cro p management systems. All cover crop management systems effectively co ntrolled hairy vetch except mowing in 1992. The corn population was re duced in mow treatments containing uncontrolled vetch. Hairy vetch mul ch suppressed some weeds in the no-till treatments in 1991, but more a nnual grass was noted late in the season with no-till into hairy vetch than with the no-cover treatments in 1992. Residual herbicide perform ance was similar across cover crop management systems, except for fall panicum control which decreased in some no-till systems. Unlike soil- applied herbicides, performance of POST herbicides was unaffected by c over crop management systems.