Effect of Planting Patterns and Inter-row Cultivation on Competition Between Corn (Zea mays) and Late Emerging Weeds

Abstract

Narrower corn row widths, higher crop densities, and interrow cultivation may be used as part of integrated weed management (IWM). During a three-year study, we tested whether these factors affected corn growth, development and grain yield at final harvest, and weed biomass when weeds were late-emerging (after the three-leaf stage of corn). Increasing corn density from 7 to 10 plants m−2or decreasing row width from 75 to 50 cm significantly increased corn leaf area index (LAI), and reduced photosynthetic photon flux density (PPFD) available for a mixture of weed species located below the corn canopy. Narrower rows and higher corn density significantly reduced biomass of late-emerging weeds. Corn yields increased significantly (10 to 15%) only when narrower rows were used. Intraspecific competition between corn plants in the higher density significantly reduced early corn growth and offset any gain in yield from reduced weed competition. In comparison to plots where late-emerging weeds grew uncontrolled, interrow cultivation did not decrease biomass of late-emerging weeds, hence did not increase corn yield. We recommend using narrower row widths to reduce weed competition and increase corn yield. Increased corn densities had no net yield benefit. Early-season weed management is crucial as the later-emerging weeds were less important in terms of their effect on yield.

Population genetic structure of the noxious weed Amaranthus retroflexus in Central Europe

“…Their vigorous aggressive growth and production of allelopathic chemicals allow them to compete strongly against other plants and significantly reduce grain yield and quality (Keeley et al, 1987;Knezevik et al, 1997;Murphy et al, 1996). Besides reduced yields, which have been observed in several crops (Gossett et al, 1992;Klingaman and Oliver, 1994;Vizantinopoulos and Katranis, 1998), compounds that may induce toxicosis and death in livestock have been documented in A. retroflexus (Kerr and Kelch, 1998).…”

Response of Corn (Zea mays) and Weeds to Planting Pattern and Herbicide Use

“…The increase in corn grain yield in narrow rows has been suggested as the decreased intraplant competition for resources (Olson & Sander, 1988) and reduction in weed competition (Forcella et al 1992;Teasdale, 1995, Murphy et al 1996Begna et al 2001). The results obtained here showed that a significant increase in grain yield could be obtained with equidistant plant arrangement due to a better resources use (soil moisture and PAR interception) while reducing the competitive effect from weeds.…”

“…(200 1 ). However, the interception obtained in the equidistant plant arrangement was higher than those reported by Murphy et al ( 1996) and Begna et al (2001). Yao & Shaw (1964), Bullock et al (1988), Teasdale (1995), Barbieri et al (2000) and Andrade et al (2002) repmted that the greater PAR interception in narrow rows at flowering was obtained when corn growth at early stages was most limited.…”

“…These results are in agreement with Forcella et at. ( 1992 ), Teasdale (1995), Murphy et at. (1996) and Begna et a/.…”

Effect ofMucunaFallow on Weed Dry Matter and Composition in Succeeding Maize

“…Shading characteristics are influenced by many factors including plant density, leaf area index and canopy architecture (Wortmann, 1993;Murphy et al, 1996). Mucuna seedling density, leaf area Downloaded by [Eastern Michigan University] at 10:19 11 October 2014 index, percentage ground cover and DM were all negatively correlated with Imperata cylindrica DM production but considerable differences were found among Mucuna varieties .…”