- Agronomic: barley, canola, flax, millet, oats, safflower, sunflower, wheat
- Crop Production: biological inoculants, crop rotation, cover crops, intercropping, no-till, conservation tillage
- Education and Training: extension, farmer to farmer, on-farm/ranch research, participatory research, workshop
- Natural Resources/Environment: soil stabilization
- Soil Management: green manures, organic matter, soil analysis
Innovative farmers in Lincoln and Spokane Counties, WA want to include a cover crop or companion crop in their rotation to raise soil organic matter levels, break disease cycles, suppress weeds, penetrate soil compaction layers, and improve soil fertility by fixing atmospheric nitrogen.
Eastern Washington State is an excellent environment for wheat production, which historically has been conducted in a cereal monoculture system. In the intermediate precipitation region (11 to 17 inches annually), a traditional dryland rotation was winter wheat – spring cereal (wheat or barley) – summer fallow. Over the last 15 years, farmers there have adopted no-till (direct seed) systems at a rate of 15 – 50%. They have replaced tillage fallow with chemical fallow, and some have diversified their rotations by including winter canola following the fallow season, which is a radical departure from treating wheat as “king.” However, the level of diversity is still low, which potentially increases the incidence of fungal pathogens like Rhizoctonia and insect pests like wireworm (click beetle larvae).
Previous research on cover crops in the area showed that species like crimson clover have potential (1986. W. Goldstein, Pullman, WA, PhD dissertation), though further study on single species cover crops in the Palouse area indicated they were not economic (2011. Dr. D. Huggins, USDA-ARS, Pullman, WA, personal communication). Current research in a similar environment in Oregon shows that interseeded companion crops in an organic system provide benefit without overly depleting soil moisture (2011. Dr. S. Machado, Columbia Basin Agricultural Research Center, Pendleton, OR, unpublished data).
Agricultural innovations in the wheat producing areas of the Midwest intrigue Pacific Northwest (PNW) farmers who travel there. Classic examples include the no-till work of Dr. Dwayne Beck at Pierre, SD, and the impressive cover cropping system on Bob Quinn’s organic farm at Big Sandy, MT. However, PNW farmers have learned they cannot adopt these practices without considerable modification. The PNW receives most of its moisture in the winter and early spring, but it has dry summers that generally preclude successful growth of the warm season crop species that contribute immensely to diversification of crop rotations.
In the spring of 2011, a group of nine farmers in Lincoln and Spokane Counties seeded experimental acres of a “cover crop cocktail (CCC),” as developed in Burleigh County, ND. The idea of a CCC versus a one-species cover crop is that the legumes will add nitrogen, the tap-rooted species will penetrate compaction layers, and “something” should grow to provide biomass. The CCC used here consisted of a nine-species mix that included three legumes, oats and a sorghum-sudangrass hybrid for biomass, and four tap-rooted broad-leaves (including turnip). The CCC was planted on ground that would otherwise be fallow, and it grew well. But contrary to the situation in North Dakota, the CCC did deplete soil moisture so the subsequent winter wheat crop had to be dusted in to wait for winter moisture and spring germination.
The farmers remain intent on making some form of cover crop work in our environment in order to increase crop diversity and improve soil health. However, they decided to modify their approach to accommodate our winter rainfall pattern. They also want to try to gain some cash value from the cover/companion crop.
- Follow through on the 2011 CCC by seeding winter or spring grains across the experimental strips in 2012 to compare with crops seeded into fallow ground
o On the Washington State University Wilke Research Farm, this will include replicated plots that compare 1) winter wheat on no-till fallow, 2) winter wheat on CCC ground, and 3) spring wheat on CCC ground.
- Grow winter wheat with winter pea as an interseeded companion crop
o Option 1 – grow and harvest the two crops together (using a Clearfield® wheat and use Beyond® herbicide for in-crop weed management) and separate seed from the two crops after harvest.
o Option 2 – grow the two crops together through fall and winter, and then spray out the broadleaf with spring-applied herbicide.
- Grow spring wheat with a modified, interseeded CCC such as crimson clover, turnips, faba bean
- If there is adequate soil moisture in the fall, seed a CCC (winter pea and tillage radish) after the spring cereal, then spray it out in the spring and leave the ground fallow for fall-seeded wheat.
The on-farm sites will be non-replicated demonstrations (each 10 acres and representing a variety of micro-climates. However, these tests will also be grown in replicated strips (18 feet by 200 feet) on the WSU Wilke Farm at Davenport, WA.
Rhizosphere ecologist Dr. Jill Clapperton of Rhizoterra Inc (formerly Lethbridge, AB), will collaborate as a project advisor and to provide soil quality and tissue testing.
The project team will extend their results to area growers primarily through field tours and workshops, where the farmer cooperators will be featured as speakers. Hard copy and online fact sheets will supplement these events. The PI will also maintain a Facebook page as a social media connection with other growers.
Project objectives from proposal:
The project will run from the summer of 2012 through the crop season of 2015, with time that fall to analyze data, write conclusions, and host workshops on the project.
- 2012 crop season - follow through on the 2011 CCC by seeding spring grains across the experimental strips in 2012 to compare with crops seeded into fallow ground
- On the Washington State University Wilke Research Farm, this will include replicated plots that compare 1) winter wheat on no-till fallow, 2) winter wheat on CCC ground, and 3) spring wheat on CCC ground.
- Fall 2012 - grow winter wheat with winter pea as an interseeded companion crop. Review after harvest and repeat in 2013 and 2014, with probably modifications.
- Option 1 – grow and harvest the two crops together (choose a Clearfield® wheat and use Beyond® herbicide for in-crop weed management) and separate the grain after harvest.
- Option 2 – grow the two crops together through fall and winter, and then spray out the broadleaf with spring-applied herbicide.
- Spring 2013 to 2015 - Grow spring wheat with a modified, interseeded CCC such as crimson clover, turnips, faba bean.
- Follow through by seeding the subsequent cereal crop across different treatments to compare the effect of various cover crop species.
- Review each season and modify the companion crop.
- Fall 2012 to 2014 - If there is adequate soil moisture in the fall, seed a CCC (winter pea and tillage radish) after the spring cereal, then spray it out in the spring and leave the ground fallow for fall-seeded wheat.
The project PI will coordinate the field demonstrations and research, outreach events, and report writing. The farmer cooperators will participate at all levels and will be primary speakers at educational events