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

Abstract

With the increasing resistance of wild oat (Avena fatua L.) to herbicides, there is a need to evaluate the potential of alternative cropping systems based on integrated weed management principles. A 5-yr field study at eight sites across Canada was used to evaluate the profitability of alternative cropping systems that have the potential to control wild oat using cultural practices in conjunction with herbicides. Cultural practices included twice the recommended seeding rates, fall-seeded winter crops, barley (Hordeum vulgare L.) silage, fallow, and alfalfa (Medicago sativa L.). Seven of the 14 cropping systems in this study did not include wild oat herbicide for three consecutive years, controlling wild oat entirely by cultural practices. Cropping system profitability varied by location. For many locations, combinations of barley silage and fall-seeded winter crops without wild oat herbicide application were as profitable as a system of canola (Brassica napus L.) and wheat (Triticum aestivum L.) with wild oat herbicide applied every year. Unprofitable systems generally included those with fallow, alfalfa, and fall-seeded winter crops in regions with rates of high winter kill. Wild oat control can be achieved with diverse cropping systems that are as profitable as conventional annual cropping that relies on herbicide control of wild oat.

Functionally diverse flax-based rotations improve wild oat (Avena fatua) and cleavers (Galium spurium) management

“…In this study, we identified that crop rotation with 3 yr of an alfalfa crop (flax-barley-alfalfa-alfalfa-alfalfa-flax) was the most consistent in managing both A. fatua and G. spurium with reduced herbicides over the long term. However, alfalfa may not be attractive for grain growers due to a reduction in cash flow during the 3 yr the alfalfa is grown (Smith et al 2018), unless there is a demand for hay the region. Nevertheless, our results show it can have a marked impact on weed populations before growing flax, a crop for which few herbicide options exist.…”

The “Sweet Spot” in the Middle: Why Do Mid-Scale Farms Adopt Diversification Practices at Higher Rates?

“…Many also incorporate unplanned biodiversity, by preserving some wild elements or natural areas within the farm, or attracting various species to planned elements (e.g., hedgerows). Such practices nurture biodiversity below ground, helping farmers build soil health, which directly supports crop growth while improving resilience to disease, drought, and floods (Gaudin et al, 2013;Poeplau and Don, 2015;Smith et al, 2018;Weisberger et al, 2019;Archer et al, 2020;Bowles et al, 2020;Wade et al, 2020). At the same time, enhancing biodiversity on the farm promotes aboveground services like pollination and pest control by providing habitat for pollinators, beneficial insects, and other wildlife (Kremen and Miles, 2012;Morandin et al, 2016;Garratt et al, 2017;Dainese et al, 2019).…”

Confronting Barriers to Cropping System Diversification

“…Farmers have known for millennia that planting the same crop in the same field year after year quickly leads to impoverished soil and unmanageable populations of disease organisms, weeds, and insect pests (Bullock, 1992;Howieson et al, 2000;Karlen et al, 2006). Similarly, recent studies have demonstrated that increasing the diversity of a simple crop rotation by even a few crops can result in not only similar or greater overall crop productivity and economic returns compared to the conventional rotation, but also improved soil fertility and lower pest populations and lower requirements for fertilizer and pesticide inputs (Smith et al, 2008(Smith et al, , 2018Davis et al, 2012;Weisberger et al, 2019;Archer et al, 2020). What is more, numerous studies have shown that the ecosystem services that arise from diversifying crop rotations, such as soil quality and fertility enhancements, can also help buffer these systems against weather variability associated with climate change (Bommarco et al, 2013;Gaudin et al, 2015;Williams et al, 2016;Bowles et al, 2020).…”