Cocklebur and Velvetleaf Interference with Soybean Grown at Different Densities and Planting Patterns

Abstract

Two common problems in soybean [Glycine max (L.) Merr.] fields are weeds and incomplete crop plant stands, and these problems may interact in their influence on soybean yield. A study was conducted in 1986 and 1987 to examine whether weed interference was influenced by soybean plant stand and planting pattern. In full stands (26 plants/m row) of soybean, common cocklebur (Xanthium strumarium L.) and velvetleaf (Abutilon theophrasti Medic.) spaced 1.5 m apart in the row decreased soybean yields 29 and 34%, respectively, in 1986 and 19 and 15%, respectively, in 1987. Decreasing the soybean stand 20, 40, and 60% without weeds resulted in yield losses of 8, 18, and 34% (across both years) in evenly spaced soybean plants, while similar stand losses caused by removal of sections of row resulted in yield losses of 14, 28, and 35%, across both years, respectively. When common cocklebur and velvetleaf were present, percentage yield decreases due to stand losses were similar to those in the weedfree treatment; there was no interaction between weed treatment and stand loss treatments. Light interception by the canopy, measured only in 1987, was higher in weedy plots than in weedfree plots, with the additional interception presumably due to the weeds. Common cocklebur produced more dry weight than did velvetleaf, but the two weeds had similar effects on soybean yield. These results indicate that, while weed competition and stand loss can both cause substantial yield losses in soybean, the effect of these factors is additive when both occur in the same field, and weed growth is not greatly enhanced by decreased competition resulting from loss of soybean stand.

Seed Priming and Field Performance of Soybean (Glycine max L.) in Response to Water Limitation

“…The use of high quality seeds with appropriate seed rate are essential to establish a suitable plant population in a soybean field for better returns (Ajouri et al, 2004;Marwat and Nafziger, 1990). Seed quality may be improved by production techniques or by seed pretreatments with water (hydro-priming), osmotic solutions (osmo-priming) and matric materials (matri-priming) (Hur, 1991;Harris et al, 1999;Kaya et al, 2008;Pill et al, 1991).…”

Variation Among U.S. Accessions of Common Cocklebur (Xanthium strumarium)1

“…], cotton (Gossypium hirsutum L.), and peanut (Arachis hypogaea L.) (Byrd Jr. and Coble 1991;Royal et al 1997;Rushing and Oliver 1998). In soybean, one common cocklebur plant per meter of row can reduce yield by 20%, and higher densities may reduce yield by 50% or more (Barrentine 1974;Bloomberg et al 1982;Marwat and Nafziger 1990;Rushing and Oliver 1998). Common cocklebur growing with crops at harvest can also reduce qual-ity.…”

Velvetleaf (Abutilon theophrasti) Effect on Corn (Zea mays) Growth and Yield in South Dakota

“…Soybean yield losses due to velvetleaf have been well documented and reviewed (3,8,11). Soybean yield can be reduced 30 to 40% at about 3 plants/m 2 and about 50% at densities at or above 16 plants/m 2 .…”