Overseeding novel forages in Oregon as a model for enhancing perennial grass pastures in the Pacific Northwest

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Commodities

Practices

• Animal Production: feed/forage, grazing management, pasture renovation
• Crop Production: no-till, pollinator habitat
• Natural Resources/Environment: biodiversity, carbon sequestration
• Soil Management: organic matter
• Sustainable Communities: new business opportunities, partnerships

Pasture-based livestock production is one of the primary agricultural production systems in Pacific Northwest (PNW), with total pasturelands exceeding 15 million hectares. These pastures are dominated by cool-season grasses and weedy annuals. Nitrogen fixing legumes and forbs are absent, and in many cases, soil health is compromised both structurally and chemically.  Both production and feeding value of cool-season grasses decrease rapidly with increasing plant maturity and physiological dormancy toward summer. This, in turn, causes reductions in grazing days, animal performance, water use efficiency, and farm income. A practical and inexpensive approach to enhance these pastures is through diversification by overseeding forage species that have high nutritive values and bioactive compounds.  This pasture improvement method may greatly increase productivity, carrying capacity, resource use efficiency, and sustainability of pastures. Additionally, it is possible to improve animal health while reducing the nitrogen input requirement using pasture forbs with high nutritive value and secondary metabolites. This practical approach to renovating compromised pastures will result in good stewardship of land and water resources. The apparent benefits of diversifying existing pasture through overseeding legumes and other forbs will be demonstrated by on farm trials, field tours and workshops. We anticipate the following outcomes: (1) increased pasture and animal productivity through extending the mid-summer grazing period and increasing forage quality, (2) reduced environmental footprint of livestock farming through increased use of N₂-fixing legumes resulting in less nitrogen fertilization and nitrate leaching, and (3) increased adoption of overseeding legumes and other forbs resulting from increased knowledge of producers.

1. Quantify the persistence and yield of pasture grasses, herbs, perennial and self-regenerating annual pasture legumes incorporated into grass-dominated pastures in both rainfed and irrigated production systems for higher animal production, extended grazing season, agronomic and ecological benefits (e.g. biological N₂ fixation, nectar source for pollinators).
2. Investigate the effect of soil amendments (lime, N, B and Mo) in legume production and biological N2 fixation potentials.
3. Compare the bio-economic efficiency (cost-benefit analyses) of overseeding forbs in grass- dominated pastures with control pastures.
4. Successfully communicate best management practices through an integrated extension message.