Cover crops are receiving renewed interest, but remain underutilized in contemporary U.S. agriculture. Cover crops can help conserve nutrients, control soil erosion, improve water infiltration and quality, reduce weed and pest pressure, increase biodiversity, and enhance soil health. Many plants can be used as cover crops, including rye, clover, sudangrass, mustard, buckwheat, and lupine. They can be grown between cash crops when soil would normally be bare, or integrated into cash crops through relay planting or intercropping. There is considerable information on cover crops from prior to the 1950s that is applicable today. In addition, current research and experience with cover crops is opening opportunity for new ideas such as direct seeding grains into cover crops and cover crops for bioremediation of soil-borne diseases.
Washington Soil Health Initiative Roadmap
Hills, K. & C. Benedict (Eds.) 2021. Washington Soil Health Initiative Roadmap. Washington State University, Pullman WA. October 2021. https://soilhealth.wsu.edu/washington-state-soil-health-roadmap/
Farmer-to-Farmer & Rancher-to-Rancher Case Studies Series
Authors include: Yorgey, G., Borrelli, K., Painter, K., Davis, H., Hall, S., Hudson, T., Neibergs, S., Reeves, M., Kruger, C., McGuire A., Finkelnburg, D., Roe, D., Brooks, E., and Kantor, S. 2016-2019. PNW Extension Publications and videos. These series explore strategies that innovative regional farmers and ranchers are using that enhance resilience to climate change and other future challenges. Case studies highlight producers in dryland and irrigated annual cropping, rangeland, and dairy production systems. Practices relate to soil health, diversification, responsive management, and many others.
Video: Reduced tillage in organic vegetable production
Sullivan D. and D.P. Collins. 2018. WSU Extension Video. This video is intended for organic vegetable producers and agricultural professionals, especially in the maritime northwest. Techniques and findings from recent research are shared to assist producers in trialing reduced tillage systems. The video covers the concept of reduced tillage organic agriculture, cover crop and weed management, and specialized equipment.
Rotational Diversification and Intensification
Kirby, E., W. Pan, D. Huggins, K. Painter, P. Bista. 2017. Chapter 5 In Yorgey, G. and C. Kruger, eds. Advances in Dryland Production Systems in the Pacific Northwest. Washington State University Extension, Pullman, WA.
Advances in Dryland Farming in the Inland Pacific Northwest
Georgine Yorgey and Chad Kruger, Eds. 2017. Washington State University Extension. Pullman, WA.
Soil physical properties, nitrogen, and crop yield in organic vegetable production systems
Cogger, C, A. Bary, A. Fortuna, L. Myhre, and D.P. Collins. 2016. Agronomy Journal. 108:1142-1154
Cover crop effects on light, nitrogen, and weeds in organic reduced tillage
Wayman, S., C. Cogger, D. P. Collins, C. Benedict, I. Burke, and A. Bary. 2015. 39:6, 647-665, DOI: 10.1080/21683565.2015.1018398
The influence of cover crop variety, termination timing, and termination method on mulch, weed cover, and soil nitrate in organic reduced-tillage
Wayman, S., C. Cogger, C. Benedict, I. Burke, D. P. Collins, and A. Bary. 2014. Renewable Agriculture and Food Systems. FirstView: 1-11. http://dx.doi.org/10.1017/S1742170514000246.
Soil Fertility in Organic Systems: A Guide for Gardeners and Small Acreage Farmers
Collins,D. C. Miles, C. Cogger, R. Koenig. 2013. Pacific Northwest Extension Publication PNW646.
Reduced Tillage on Organic Farms Virtual Field Day
WSU researchers and extension educators are researching different methods for reducing tillage in organic vegetable production. This video demonstrates termination of barley and vetch cover crops with a roller/crimper and flail mower.
Mustard Green Manures
On-farm research has been conducted since 1999 to determine the benefits of mustard green manures and to improve their effectiveness. They are being used in irrigated regions of Eastern Washington to improve soil quality, control wind erosion, and manage soilborne pests.
Potential nitrogen contributions from legumes in Pacific Northwest apple orchards
Mullinix, K. and Granatstein, D. 2011. Intl. J. Fruit Sci. 11:74-87.
Cover crops in orchards and vineyards
WSU Tree Fruit Research and Extension Center webpage. Contains links to additional resources and presentations.
Influence of orchard floor management and compost application timing on N partitioning in organically managed apple trees
TerAvest, D., J.L. Smith, L. Carpenter-Boggs, L. Hoagland, D. Granatstein, and J.P. Reganold. 2010. HortScience. 45:637-642.
Sustainability trade-offs in organic orchard floor management
Granatstein, D., Wiman, M., Kirby, E., Mullinix, K. 2010. Acta Hort. 873:115-122.
Research knowledge and needs for orchard floor management in organic tree fruit systems
Granatstein, D. and E. Sanchez. 2009. Intl. J. Fruit Science 9:257-281.
Cover Crops Influence Meadow Vole Presence in Organic Orchards
M. R. Wiman, Kirby, E. M., Granatstein, D. M., Sullivan, T. P. HortTechnology July–September 2009 19(3).
Comparing tillage and mulching for organic orchard performance
Wiman, M., Kirby, E., Granatstein, D., Mullinix, K. 2008. Poster presented at 2008 BIOAg Research Symposium.
Mulching options for Northwest organic and conventional orchards
Granatstein, D. and K. Mullinix. 2008. HortScience 43(1):45-50.
Effects of Ground Cover Management Strategies on Yield and Nitrogen Supply in Organic Apple Production Systems
Poster presentation – BIOAg Research Symposium 2008.
Cover Crops as a Floor Management Strategy for Pacific Northwest Vineyards
Olmstead, M. 2006. EB2010, WSU Extenson.