Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2007
Publication Date: 6/5/2007
Citation: Williams, M.M. II, Lindquist, J.L. 2007. Influence of planting date and weed interference on sweet corn growth and development. Agronomy Journal. 99:1066-1072. Interpretive Summary: Typical dates for sweet corn planting in the north-central USA influence sweet corn canopy development. This variation in canopy development influences the crop’s ability to endure competitive stress and suppress weeds, resulting in interactive effects of planting date and weed interference on the crop. Under central Illinois conditions and weeds common to the region, sweet corn growth appears to give the crop a distinct competitive advantage when planted mid-June, compared to early-May planting. These results largely explain the influence of planting date on critical period of weed control in sweet corn. The impact of this research is that it provides knowledge critical to the development of more effective weed management systems in sweet corn.
Technical Abstract: Crop planting date and canopy density influence interactions between weeds and sweet corn (Zea mays L.); however, little is known about sweet corn growth response to weed interference. Field studies were conducted in 2004 and 2005 near Urbana, Illinois to quantify the influence of planting date and weed interference on growth of sweet corn height, leaf area, aboveground biomass, and phenological development. Crop growth response to weed interference (presence or absence) was determined for sweet corn planted early-May (EARLY) and late-June (LATE). Dominant weed species included barnyardgrass (Echinochloa crus-galli (L.) Beauv.), common lambsquarters (Chenopodium album L.), common purslane (Portulaca oleracea L.), green foxtail (Setaria viridus (L.) Beauv.), redroot pigweed (Amaranthus retroflexus L.), and velvetleaf (Abutilon theophrasti Medicus) at densities ranging from 95 to 256 plants m-2. Weed interference reduced sweet corn’s absolute height growth rate, maximum leaf area index (LAI), absolute LAI growth rate, with some of the largest effects on crop growth observed in the EARLY planting date. Silk emergence was delayed by weeds for EARLY planted sweet corn, but not LATE. Moreover, the LATE planting date resulted in 9% taller crop plants with 36% lower maximum LAI. Relative to an EARLY planting date, lower yield losses due to weeds for LATE sweet corn correspond to greater resiliency of crop growth and silk emergence to weed interference.