9 The Business of Prairie Agriculture Better Farming | January 2024 and unpublished data from crops grown with increased O3 pollution in open-air field experiments over the past 20 years, authors performed a comprehensive analysis of the impact of O3 on crop physiology and production in five C3 and four C4 crops. “We focused on field experiments and quantified crop responses to a specific increase in O3 pollution. This new method quantitatively showed that C3 crops are more sensitive to elevated ozone than C4 crops,” Li says. The reasoning behind such a conclusion could have something to do with the differences in leaf anatomical features, stomatal conductance and/or metabolic rates between the C3 and C4 crops. In C3 plants, reactive oxygen species from O3 degradation can damage the mesophyll cells where photosynthesis occurs. In C4 plants, however, the spatial separation of the C4 photosynthesis pathway helps prevent O3 from infiltrating the bundle sheath cells where sugars are made. Also, C4 crops generally have lower stomatal conductance than C3 crops, potentially resulting in less O3 uptake in C4 crops. These factors likely account for C4 plants’ superior tolerance of O3. “This study enhances our understanding of the mechanisms of crops response to elevated O3 and highlights practical relevance for crop management and O3 tolerance improvement,” Li says. Ozone pollution is increasing in many parts of the world. This study quantitatively showed that O3-induced reductions in plant function and productivity are more severe in C3 crops than in C4 crops, likely because O3 interacts differently with the C3 and C4 photosynthesis pathways. Based on this finding, agricultural lands in polluted environments can be managed to have improved overall performance. C4 crops, particularly bioenergy feedstocks, can maintain productivity in regions with high O3. BF April Wendling is a CABBI communications specialist at the University of Illinois Urbana-Champaign. Wild buckwheat is an annual weed that produces about 1,200 seeds per plant and can cause crop lodging, making swathing and combining difficult, if not controlled. What to look for • Seedlings: Look for linear cotyledons positioned at 120 degrees from each other. True leaves are arrow-shaped with pointy tips and pointed basal lobes. Leaves are alternately arranged and petioled with entire margins*. • Mature Plants: Look for 1-3 ft. long, slightly angular stems that trail on the ground or twine on other plants. Leaves are heart-shaped, pointed, long, alternate and smooth. The flowers are greenish-white, small and borne in the leaf axils or at the tip of branches. Five sepals enclose a single seed**. Count the cost • Yield loss in wheat: 12% loss can occur with five plants/m2 and 22% loss with 30 plants/m2**. • Yield loss in flax: Up to 10-20% loss has been reported with 5-15 plants/m2. Yield loss can vary depending on when weeds are present (before or after crop emergence)**. When to scout • Take several weed counts across the field. Check low spots for patches. Scout fields early because it is most sensitive to herbicides in its early stages**. How to control • The earlier you can apply herbicides, the better control you’ll have. Consider applying a tank-mix partner with your glyphosate pre-seed burn-off such as Intruvix™ II herbicide. WILD BUCKWHEAT *Weeds of the Prairies: Alberta Agriculture **Government of Manitoba Crop and Agronomy Information site. https://www.gov.mb.ca/agriculture/crops/weeds/wild-buckwheat.html Always read and follow label instructions. Member of CropLife Canada. FMC, the FMC logo and Intruvix are trademarks of FMC Corporation or an affiliate. ©2024 FMC Corporation. All rights reserved. 8190 - 12/23 8190 Weed of the Month Series_Wild Buckwheat.indd20123-12-06 9:26 AM 2023-12-06 9:26 AM Research Ozone has a significant impact on crop yield. Tracy Miller photo
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