Effects of Common Wheat (Triticum aestivum) Management Alternatives on Weed Seed Production¹

Abstract

Common management alternatives were compared in a factorial arrangement for 2 yr to determine their effects on green foxtail and yellow foxtail seed production in spring wheat in the Northern Great Plains of the United States. Seed production was measured twice, at wheat harvest (in August) and postharvest (after first lethal frost in autumn). Management alternatives were early, middle, and late crop-sowing dates; no-till, chisel, and moldboard plow tillage systems; and broadleaf herbicide only and broadleaf herbicide plus fenoxaprop applications. Fenoxaprop reduced foxtail seed production at wheat harvest but not at postharvest. Early sowing also decreased seed production at wheat harvest but increased postharvest seed production. Tillage system had no consistent effects on foxtail seed production. Postharvest seed production often was greater than or equal to that at wheat harvest regardless of management system. These results indicate that in-crop management alternatives, such as postemergence grass herbicide and early crop sowing, may lower the number of foxtail seeds at harvest substantially, but they must be accompanied by postharvest weed control to reduce overall seed production.

Tillage effect on reproductive output by foxtail cohorts in corn and soybean

“…In 1996, yellow foxtail panicles were slightly larger than similar plants in 1997 (Table 4), but this fact does not give insight into the disparity in seed production. Kegode et al (2003) reported that late sowing can reduce the size of foxtail panicles, but this was not consistent for yellow foxtail over a 2-yr period. Yellow foxtail plants that emerged late had longer panicles in 1996 (16%) than in 1997, when they were 28% shorter.…”

“…Green foxtail, on the other hand, responded uniformly between 1996 and 1997 with a 10 to 34% reduction in panicle length when crop sowing was delayed (Kegode et al 2003). In our study, the absence of significant interactions with tillage system, the consistently higher number of primary tillers and panicles per plant in NT and MP compared with other tillage systems (Table 2), and consistently higher seed production in NT corn compared with other tillage systems ( Figure 3) show that relatively reliable estimates for seed production were obtained for this species.…”

“…Green foxtail and yellow foxtail are important weeds in many crops grown in North America, and they are known to produce numerous seeds (Kegode et al 1999a(Kegode et al , 1999b(Kegode et al , 2003Santelmann et al 1963;Vanden Born 1971). Because factors regulating foxtail seed production are poorly understood, there is a need to determine the magnitude of seed production of plants that escape control.…”

Effects of Changes in Flax (Linum usitatissimumL.) Density and Interseeding with Red Clover (Trifolium pratenseL.) on the Competitive Ability of Flax Against Brassica Weeds

“…This was reflected in the low amount of nitrogen in their seed and biomass, which suggests that the presence of flax and red clover caused a reduced availability of nutrients for the weeds (Norris et al 2001;Weiner et al 2001). This suggests that flax intercropping with red clover or growing alone, limited the access to resources for the weed, thus affecting their offspring, as noted by Martinez-Ghersa et al (2000) and Kegode et al (2003).…”

“…It is also expected that these practices can reduce the availability of resources for weeds and adversely affect their growth by diminishing their reproductive capacity (Kegode et al 2003), thus, acting as a suppressor, a suitable feature for long-term weed management.…”