Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 17, 2004
Publication Date: November 18, 2004
Citation: Molin, W.T., Hugie, J.A. 2004. Prickly sida (sida spinosa) and spurge (euphorbia hyssopifolia) response to wide row and ultra narrow row cotton (gossypium hirsutum) management systems. Weed Technology 4:222-229. Interpretive Summary: Ultra narrow row cotton management systems differ from wide row in that more shading develops under the crop canopy. This shading can reduce weed growth. This paper describes the effects of ultra narrow row systems on the growth of two weed species. The results show that ultra narrow row systems can limit growth of weeds. Such practices could serve to reduce herbicides in the environment, reduce the competitive ability of weeds, and decrease weed seed production.
Technical Abstract: A 4-yr field study was conducted from 1998 to 2001 to evaluate the response of prickly sida and hyssop spurge growing in cotton in either ultra narrow row (UNR) and wide row (WR) cotton management systems. Weeds surviving pre- and postemergence herbicide treatments were harvested just prior to defoliation and morphological characteristics were compared. Prickly sida growth from ultra narrow row cotton was significantly reduced with regard to number of main stem nodes, primary, secondary, and tertiary branching, number of seed capsules produced, and dry weight. However, plant height was not affected by row spacing. Spurge growth was significantly reduced with regard to branching and fresh weight but not height. These results show that UNR spacing in cotton may suppress development of prickly sida and spurge by reducing vegetative and reproductive biomass. The reduction in seed and seed capsule production of prickly sida will likely reduce its reproductive potential and also diminish subsequent seed rain and soil seed bank reserves. Thus, a potential benefit of ultra narrow row cotton management systems may be to reduce the competitive ability of weeds and decrease seed production.