Dr. Charles M. Geddes, Ph.D., P.Ag.

Image Charles M. Geddes
Research Scientist - Weed Ecology and Cropping Systems
  • Herbicide-resistant plants
  • Weed ecology, biology and management
  • Integrated weed management
  • Weed seedbank dynamics
  • Crop/weed interference
  • Long-term agroecosystem experiments

Current research and/or projects

16. Principal Investigator. Title "Old plots, new hypotheses: Toward a revitalized AAFC long-term agroecosystem experiment (LTAE) network." AAFC Management Solicited Initiative. 2019-2022.

15. Principal Investigator. Title "Development of an integrated weed management (IWM) package to mitigate and manage glyphosate-resistant weeds in soybean." WGRF, MPSG, CAP Ag Action MB Program. 2019-2024.

14. Principal Investigator. Title "Management of glyphosate-resistant kochia in western Canadian cropping systems." ICA Cluster - CAP, WGRF, MPSG, MWBGA, AAFC. 2018-2023.

13. Principal Investigator. Title "Weed seed-suppressive soils: Managing herbicide-resistant weed populations at the source." AAFC A-base. 2018-2021.

12. Co-Investigator. Title "Beneficial insects in Prairie crops: quantifying the value and vulnerability of biological pest control." AAF, AWC, AB, SWDC. 2019-2022.

11. Co-Investigator. Title "Development of improved protocols for the culture of arbuscular mycorrhizal fungi with high symbiotic potential according to the analyses of soil microbiome." AAFC A-base. 2018-2021.

10. Co-Investigator. Title "Delivery of an innovative winter wheat package to achieve sustainable wheat production in the Canadian Prairies." CNW Cluster - CAP. 2018-2023.

9. Co-Investigator. Title "Glyphosate-resistant kochia/Russian thistle surveys." WGRF. 2018-2023.

8. Co-Investigator. Title "Identifying agronomic and environmental benefits and drawbacks of diverse crops in cereal/canola/pulse crop rotations on the semi-arid Canadian Prairies. DFC Cluster - CAP. 2018-2023.

7. Co-Investigator. Title "Improving the management of sclerotinia stem rot of canola using fungicides and better risk assessment tools. CAR Cluster - CAP. 2018-2023.

6. Co-Investigator. Increasing the suitability of the Holos model for life cycle analysis through production cycle inputs, collaborative/open source development, and the development of representative farm systems. AAFC A-base. 2019-2022.

5. Co-Investigator. Integrating multiple beneficial management practices (BMPs) in an organic cropping system: Soil health, weed and insect interactions. AAFC A-base. 2018-2021.

4. Co-Investigator. Title "Long-term sustainable canola production - All phases rotations. WGRF, ACPC. 2017-2020.

3. Co-Investigator. Title "Manipulating agronomic factors for optimum canola harvest timing, productivity and crop sequencing." CAR Cluster - CAP. 2018-2023.

2. Co-Investigator. Title "Mitigating herbicide resistance - Investigating novel integrated weed maangement systems." WGRF, ACPC, ABC, SWDC. 2016-2021.

1. Co-Investigator. Title "The right balance: Management strategies for plugging organic soil health constraints and moving forward." OS Cluster III - CAP. 2018-2023.


Education and awards

Doctor of Philosophy (Plant Science), University of Manitoba, 2018

Bachelor of Science (Agroecology), University of Manitoba, 2012

Key publications

  1. Tidemann BD, Harker KN, Geddes CM, Blackshaw RE, Lupwayi N, Shirtliffe S, Willenborg C, Johnson EN, Gulden R, Turkington TK, Semach G, Mulenga A (2020) Mitigating herbicide resistance: Incorporating integrated weed management strategies. Poster presentation at the Canadian Weed Science Society Virtual Meeting November 2020. Abstract 49. Available at https://www.weedscience.ca/resources/annual-meeting-archived-files/

    2020 - View publication details

  2. Geddes, C.M., and M.T. Kimmins. 2020. Does crop competition impact the expression of a herbicide-resistant weed phenotype? 2020 Annual Meeting of the Canadian Weed Science Society. November 23-27, 2020. [Online]. (Poster Presentation).

    2020 - View publication details

  3. Geddes, C.M., R.H. Gulden, E.N. Johnson, A. Mulenga, and C.J. Willenborg. 2020. Manipulating kochia [Kochia scoparia (L.) Schrad.] seed production through phenology-based weed control. 2020 Annual Meeting of the Canadian Weed Science Society. Nov 23-27, 2020. [Online]. (Oral Presentation).

    2020 - View publication details

  4. Larney, F.J., Catton, H.A. Geddes, C.M., Lupwayi, N.Z., Forge, T.A., Lemke, R.L., and Helgason, B.L. 2020. Cover cropping for organic carrot production. Oral presentation. Organic Alberta and Holistic Management Canada Conference, January 31-February 2, 2020, Camrose, AB.

    2020 - View publication details

  5. Nair, J., Turkington, T.K., Blackshaw, R., Geddes, C.M., Lupwayi, N.Z., Xu, S., Yang, J., Yang, H.E., Wang, Y., McAllister, T.A. (2019). Impact of field fungal contamination of barley on ensiling properties, nutritional quality and the microbiome of barley silage. Grass and Forage Science, [online] 74(2), 231-243. http://dx.doi.org/10.1111/gfs.12419

    2019 - View publication details

Research facility

5403 1st Avenue South
Lethbridge, AB T1J 4B1


Alberta Institute of Agrologists (member)

American Society of Agronomy (member)

Crop Science Society of America (member)

Canadian Society of Agronomy (member)

Canadian Weed Science Society (member)

Weed Science Society of America (member)