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CHOOSING THE BEST COVER CROP FOR AN ORGANIC VEGETABLE ROTATION IS COMPLICATED. Legume-cereal cover crop mixes are often promoted because they combine the ability of legumes to add atmospheric nitrogen to the system through biological fixation in root nodules, and the ability of the cereals to scavenge nitrogen that is prone to leaching during the winter. Efficient nitrogen use is especially pertinent in organic systems because the cost per unit of nitrogen in organic fertilizers is relatively high. Cover crops can provide important ecosystem services (soil improvement, nutrient cycling, weed suppression, etc.) and therefore are crucial in sustainable agriculture. An important question to ask is whether or not legume-cereal mixtures are a good fit in tillage-intensive organic vegetable production systems that are common in California? This video addresses that question using data from Dr. Eric Brennan's short-term and long-term research on organic vegetable studies conducted in the major region for high-value vegetable production in California. This research has shown that the performance (i.e., biomass production, ground cover, weed suppression, potential nitrogen fixation) of cover crop mixtures can vary markedly between and within farms based on soil type, land history, cover crop management (i.e., seeding rate, planting method, planting date, mixture composition), and climate (i.e., winter rainfall and temperature). The drawings in this video were inspired by the book ' Blah Blah Blah - What to do when words don't work ' (Dan Roam). Dr. Brennan showed this video at the 2014 Annual International Conference of the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America in Long Beach, California. This novel presentation method allowed for more time for questions and interaction with the audience. Dr. Brennan is a scientist with the USDA-ARS (United Stated Department of Agriculture, Agricultural Research Service) in Salinas, CA. Link to DOWNLOAD BRENNAN PUBLCATIONS for free http://www.researchgate.net/profile/Eric_Brennan -RELATED VIDEO https://www.youtube.com/watch?v=zLvJLHERYJI -SPECIFIC PUBLICATIONS RELATED TO THIS VIDEO http://www.researchgate.net/publication/232678868_Winter_Cover_Crop_Growth_and_Weed_Suppression_on_the_Central_Coast_of_California http://www.researchgate.net/publication/43284345_Seeding_Rate_and_Planting_Arrangement_Effects_on_Growth_and_Weed_Suppression_of_a_Legume-Oat_Cover_Crop_for_Organic_Vegetable_Systems https://www.researchgate.net/publication/261133417_Winter_Cover_Crop_Seeding_Rate_and_Variety_Affects_during_Eight_Years_of_Organic_Vegetables_I.Cover_Crop_Biomass_Production http://www.researchgate.net/publication/261133222_Winter_Cover_Crop_Seeding_Rate_and_Variety_Affects_during_Eight_Years_of_Organic_Vegetables_II._Cover_Crop_Nitrogen_Accumulation