Interference between Redroot Pigweed (Amaranthus retroflexus L.) and Cotton (Gossypium hirsutum L.): Growth Analysis

Abstract

Redroot pigweed is one of the injurious agricultural weeds on a worldwide basis. Understanding of its interference impact in crop field will provide useful information for weed control programs. The effects of redroot pigweed on cotton at densities of 0, 0.125, 0.25, 0.5, 1, 2, 4, and 8 plants m-1 of row were evaluated in field experiments conducted in 2013 and 2014 at Institute of Cotton Research, CAAS in China. Redroot pigweed remained taller and thicker than cotton and heavily shaded cotton throughout the growing season. Both cotton height and stem diameter reduced with increasing redroot pigweed density. Moreover, the interference of redroot pigweed resulted in a delay in cotton maturity especially at the densities of 1 to 8 weed plants m-1 of row, and cotton boll weight and seed numbers per boll were reduced. The relationship between redroot pigweed density and seed cotton yield was described by the hyperbolic decay regression model, which estimated that a density of 0.20–0.33 weed plant m-1 of row would result in a 50% seed cotton yield loss from the maximum yield. Redroot pigweed seed production per plant or per square meter was indicated by logarithmic response. At a density of 1 plant m-1 of cotton row, redroot pigweed produced about 626,000 seeds m-2. Intraspecific competition resulted in density-dependent effects on weed biomass per plant, a range of 430–2,250 g dry weight by harvest. Redroot pigweed biomass ha-1 tended to increase with increasing weed density as indicated by a logarithmic response. Fiber quality was not significantly influenced by weed density when analyzed over two years; however, the fiber length uniformity and micronaire were adversely affected at density of 1 weed plant m-1 of row in 2014. The adverse impact of redroot pigweed on cotton growth and development identified in this study has indicated the need of effective redroot pigweed management.

Global Meta‐Analysis of Cotton Yield and Weed Suppression from Cover Crops

“…Weeds reduce overall yields in many crops, including cotton (Wood et al, 2002;Barnett and Steckel, 2013;Ma et al, 2015). Effect sizes for individual studies were <0.95 for 101 (58%) studies, between 0.95 and 1.05 for 43 (25%) studies (negligible cover crop effect), and >1.05 for 30 (17%) studies.…”

Harmonic Differential Quadrature Method for Surface Location Error Prediction and Machining Parameter Optimization in Milling

“…The second one is to generalize the optimization model for selecting optimal geometry parameters of the cutter. The third one is to fuse the present method with some on-line chatter detection techniques [41,42] for high performance milling.…”

Weed management in cotton (Gossypium hirsutum L.) through weed-crop competition: A review

“…Competitive interference of A. palmeri indicated that 10 plants per 9.1 m row resulted in a 45% reduction in canopy volume at 10 weeks after planting and reduced cotton biomass to 50% by 8 weeks after planting (Morgan et al, 2001). Similarly, A. hybridus can grow taller than cotton and can reach up to 3 m thereby, shade the crop plants (Ma et al, 2015b). This weed at a density of 0.3 plants per m of row could cause a yield reduction of around 50% (Ma et al, 2015b).…”

“…Similarly, A. hybridus can grow taller than cotton and can reach up to 3 m thereby, shade the crop plants (Ma et al, 2015b). This weed at a density of 0.3 plants per m of row could cause a yield reduction of around 50% (Ma et al, 2015b). To further enhance the problems, over-reliance on glyphosate for weed management is favouring many weeds to rapidly evolve resistance to this herbicide (Flessner et al, 2015;Webster and Grey, 2015).…”