Integrating Herbicide-Resistant Corn Technology in a Kura Clover Living Mulch System

Abstract

Previous research has shown that with adequate suppression, kura clover (Trifolium ambiguum M. Bieb.) can be managed as a living mulch in corn (Zea mays L.); however, significant yield loss was observed in some environments. This study evaluated two herbicide-resistant corn hybrids at three levels of kura clover living mulch suppression over multiple environments. In 1999 and 2000 near Arlington and in 2000 near Lancaster, WI, glyphosate [N-(phosphonomethyl)glycine]-resistant corn (Roundup Ready corn, RRC) and glufosinate [2-amino-4-(hydroxymethylphosphinyl) butanoic acid]-resistant corn (Liberty Link corn, LLC) hybrids were planted where kura clover had been (i) killed for monocrop corn, (ii) strongly suppressed with glyphosate and dicamba (3,6-dichloro-2-methoxybenzoic acid), or (iii) lightly suppressed with only glyphosate. Suppressed kura clover also had a 25-cm clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) plus dicamba-killed band into which corn was planted. Subsequent postemergence applications of glyphosate or glufosinate herbicide were made for each hybrid. Corn whole-plant yield ranged from 17.3 to 19.9 Mg ha−1, and grain yield ranged from 10.8 to 12.3 Mg ha−1. Yield of whole-plant and grain across both corn hybrids did not differ between monocrop corn and corn in strongly suppressed kura clover. Whole-plant yield of monocrop corn was 8 to 11% greater and grain yield 8 to 9% greater than in lightly suppressed kura clover, respectively. Both hybrids had similar corn whole-plant yield, but LLC grain yield was lower than that of RRC. Kura clover recovery in the season following corn production was similar among living mulch suppression treatments by mid-July. Herbicide-resistant corn technology allowed for consistent kura clover living mulch management with little or no whole-plant or grain yield loss.