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.