Weed Management in Organic Vegetable Production Systems in California: Implications for Canadian Growers

Nathan Boyd¹ and Eric Brennan²
(1) Nova Scotia Agriculture College, Truro, NS, Canada
(2) USDA-ARS, Salinas, California

Abstract
Weed control in organic vegetable production systems is challenging and accounts for a large portion of production costs.  In California, legume-cereal cover crop mixes are common components of organic vegetable crop rotations.  These mixes tend to be weedy due to the poor competitive ability of the legume component and this can increase weed problems in subsequent crops. 

Multiple trials were conducted to examine the impacts of cover crop variety and seeding rate on weed population dynamics, soil quality, soil water storage, yield and profitability.   Additional trials were conducted to evaluate the use of multiple physical weed control options for use in a variety of crops. 

Cover crop density and composition impacted weed growth, density, and seed production.  The presence of cover crops impacted a wide range of additional variables including crop yield.  Our results suggest that a poorly selected rotation will increase the weed seed bank and can exacerbate future weed problems.  Weeds occurring within vegetable crops can be adequately controlled using a variety of techniques.  For example, stale seedbeds formed using flamers or a range of cultivation implements can significantly reduce in-crop weed densities.  A range of organic weed management options for horticultural crops will be discussed as well as the potential for their adoption by Canadian growers.
 

Abstract of presentation given at the 2010 Guelph Organic Conference Natural Sciences Research Symposium.


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Posted March 2010