Diverse Rotations and Optimal Cultural Practices Control Wild Oat (Avena fatua)

Abstract

In western Canada, more money is spent on wild oat herbicides than on any other weed species, and wild oat resistance to herbicides is the most widespread resistance issue. A direct-seeded field experiment was conducted from 2010 to 2014 at eight Canadian sites to determine crop life cycle, crop species, crop seeding rate, crop usage, and herbicide rate combination effects on wild oat management and canola yield. Combining 2× seeding rates of early-cut barley silage with 2× seeding rates of winter cereals and excluding wild oat herbicides for 3 of 5 yr (2011 to 2013) often led to similar wild oat density, aboveground wild oat biomass, wild oat seed density in the soil, and canola yield as a repeated canola–wheat rotation under a full wild oat herbicide rate regime. Wild oat was similarly well managed after 3 yr of perennial alfalfa without wild oat herbicides. Forgoing wild oat herbicides in only 2 of 5 yr from exclusively summer annual crop rotations resulted in higher wild oat density, biomass, and seed banks. Management systems that effectively combine diverse and optimal cultural practices against weeds, and limit herbicide use, reduce selection pressure for weed resistance to herbicides and prolong the utility of threatened herbicide tools.

Floristic Biodiversity of Weed Communities in Arable Lands of Istria Peninsula (From 2005 to 2017)

“…An opposite trend was observed for Avena fatua which reduced in importance and particularly declined in permanent crops (-12 points) and alfalfa (-10 points). It probably happened due to the effectively combined diverse and optimal cultural practices and herbicide use against this annual weed (Harker et al, 2016).…”

The profitability of diverse crop rotations and other cultural methods that reduce wild oat (Avena fatua)

“…Establishing alfalfa for only 2 yr of production was not as profitable as other crops. However, canola returns in 2014 after alfalfa were generally high and the wild oat population was low (Harker et al 2016). Yearly alfalfa returns can be high once the crop is established, but there was a cost and forgone income to establish the alfalfa stand and a cost to terminate the alfalfa.…”

“…A field study at eight locations in Canada was run from 2010 through 2014 (Harker et al 2016). Six of the sites were in the prairies of western Canada (Edmonton, Lacombe, and Lethbridge, AB; Scott and Saskatoon, SK; Carman, MB) and two were in eastern Canada (New Liskeard, ON; Normandin, QC).…”

“…While clopyralid was effective, it was a high-cost alternative. Plant and wild oat density measurements were taken in the field study and were reported by Harker et al (2016). Field operations were similar across locations, but tillage and seed bed preparation were more intensive at Normandin.…”

An ecological perspective on managing weeds during the great selection for herbicide resistance

“…A large-scale research consortium, involving five Canadian provinces from 2010 to 2014, found that combining longer crop rotations that included diverse crop phenologies with optimal crop seeding rates and reduced soil disturbance could create large reductions in herbicide-resistant A. fatua infestations and improve net economic returns to management. 41 Implementation of such an approach at landscape scales would create a shifting mosaic wileyonlinelibrary.com/journal/ps of contrasting crop phenologies across growing seasons, preventing any one weed life history group (e.g., summer annuals) from becoming too entrenched at broad spatial scales. Similar weed management benefits have been found from the diversification of corn-soybean production systems.…”