Keeping Legumes in Pasture Stands Longer
Project Title
Sustaining the Legume Component of Grazed Pasture Mixtures for Summer Grazing and Stockpiling Complex Mixtures in Eastern Canada
Researchers
Yousef Papadopoulos Ph.D. yousef.papadopoulos@agr.gc.ca
Yousef Papadopoulos Ph.D., John Duynisveld, Gilles Bélanger, Ph.D., Gaëtan Tremblay, Ph.D., Marie-Noëlle Thivierge Ph.D., Julie Lajeunesse, Denis Angers Ph.D.,Tanya Dykens, Abdelali Hannoufa Ph.D. (Agriculture and Agri-Food Canada), Carole Lafrenière, Ph.D. (Université du Québec en Abitibi-Témiscamingue) Alan Fredeen, Ph.D. (Dalhousie University), Ira Mandell, Ph.D. (University of Guelph),Bill Thomas, Jonathan Wort (Perennia), Les Halliday, Ph.D. (PEI Department of Agriculture), Zhongmin Dong Ph.D. (Saint Mary's University), Huguette Martel (Ministère de l'Agriculture, de l'Alimentation et des Pêcherie du Québec); David Dykstra (New Brunswick Department of Agriculture, Aquaculture and Fisheries)
| Status | Project Code |
|---|---|
| Completed March, 2023 | FRG.09.17 |
Background
Results from previous Beef Science Cluster projects have identified legume-grass mixtures that perform well in Central and Eastern Canada. However, the legumes have quickly dropped out of the mixed stands, leading to a decline in pasture and animal productivity. The potential ability to establish legumes using sod- or frost-seeding has been demonstrated, but results are variable and likely depend on grazing and fertility management. Carbon sequestration in soil organic matter can also be enhanced by adding legumes to grassland. Overcoming challenges related to legume establishment, seedling vigor, acidic soils, and moisture extremes would help keep legumes in pasture stands and benefit pasture health, carbon sequestration and animal productivity.
Objectives
- To increase the amount of herbage yield and quality of complex pasture mixtures through nutrient management strategies, refined grazing management, novel and enhanced stand renovation technologies, and plant genetics.
- Identify cultivars and new germplasm with significant adaptation to grazing, extreme weather events, and/or negative soil attributes.
- Complex mixtures of legumes and grasses will be stockpiled for extended grazing and a database of soil nutrient changes in response to management as it relates to soil carbon sequestration and the impact on pasture productivity will be developed.
What They Did
A number of experiments were conducted:
- Assessing Seedling Vigor: Evaluated legume species and chitosan seed coatings.
- Field Evaluation of Root Growth Promotants: Tested chitosan-coated legume seeds in existing grass stands.
- Chitosan Coated Alfalfa and Birdsfoot Trefoil Seeds: Assessed chitosan-coated seeds’ impact on germination.
- Impact of Fertility Management: Evaluated effects of fertility treatments and seeding methods.
- Effect of Seeding Method and Forage Management: Studied seeding methods and forage management impact.
- Effect of Seeding Method on Forage Legume Establishment: Compared seeding methods at multiple locations.
- Grazing management study: Evaluated grazing’s influence on legume establishment, animal weight gain, and soil carbon dynamics.
What They Learned
- Sod seeding didn’t significantly benefit legume content compared to frost seeding.
- Nitrogen and sulfur fertilization increased yield and legume content.
- Legume species/cultivar choice influenced establishment success.
- Chitosan coatings showed promise but require further research.
- High stock density grazing increased grazing days significantly.
- Declines in root and soil carbon levels were observed, possibly influenced by prior manure applications and drought.
- High stock density reduced carbon emissions per steer per day, attributed to assumed soil carbon sequestration.
- New alfalfa cultivar showed tolerance to lower soil pH conditions.
- Birdsfoot trefoil cultivars demonstrated tolerance to acidity, waterlogging, and persistence.
- Red clover significantly contributed to fall stockpile yield.
What It Means
The studies collectively underscore the importance of fertility management, legume species/cultivar choice, and the potential benefits of chitosan seed coatings for sustainable pastures. High stock density grazing significantly enhances grazing days and weight gain. However, achieving legume establishment goals remains a challenge, and soil carbon dynamics exhibit complex responses. Genetic traits like aluminum tolerance in legumes play a crucial role in pasture success, emphasizing the need for continued research and monitoring.