Estimating Plant-Available Nitrogen Contribution from Cover Crops Webinar

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Learn how to estimate how to estimate the quantity of plant-available Nitrogen provided by decomposition of winter cover crop residues. In this Webinar, Dan Sullivan and Nick Andrews of Oregon State University will discuss how to use the OSU Cover Crop Calculator to make site-specific predictions of how much organic fertilizer (and money) are saved by judicious use of cover crops in diversified vegetable cropping systems.

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About Nick Andrews

Nick Andrews earned his BS in Horticulture at OSU and an MS in Entomology from the University of Reading in England. He has worked with the UK Extension Service as a Vegetable Entomologist, as an independent IPM consultant to Hood River orchardists, and an organic inspector for Oregon Tilth. Since December 2005 he has served as the OSU Metro Area Small Farm Extension Horticulturist. His work focuses on ecological vegetable production in Multnomah, Washington and Clackamas Counties. Nick and the OSU Small Farms team won four awards for their work in 2008. Nick developed the OSU Cover Crop Calculator with Dan Sullivan and Jim Julian, is conducting on-farm cover crop research and has started a research & education composting facility at the North Willamette Research & Extension Center in Aurora. Nick also organizes workshops for small farmers, including the OSU Small Farms Conference, North Willamette Horticulture Society Organic Crops Section and Growing Farms, a beginning farmer training series.

About Dan Sullivan

Dan Sullivan is Research and Extension Soil Scientist in the Department of Crop & Soil Science at Oregon State University. His research and Extension progam seeks to develop value-added uses for organic materials, and to assist farmers and agri-business in implementing effective and economical nutrient management practices. Dan joined OSU in 1995, and has had the opportunity to serve as advisor for over 20 graduate students. He is author of over 20 Extension publications.

About eOrganic

eOrganic is the Organic Agriculture Community of Practice at Our website at contains articles, videos, and webinars for farmers, ranchers, agricultural professionals, certifiers, researchers and educators seeking reliable information on organic agriculture, published research results, farmer experiences, and certification. The content is collaboratively authored and reviewed by our community of University researchers and Extension personnel, agricultural professionals, farmers, and certifiers with experience and expertise in organic agriculture.


Published March 31, 2010

This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.