Submitted to: Weed Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/1/2004
Publication Date: 5/1/2004
Citation: Young, F.L. 2004. Long-term weed management studies in the Pacific Northwest. Weed Science. 52:897-903. Interpretive Summary: The Pacific Northwest (PNW) has been recognized as one of the most erosive regions of agricultural land in the United States. Water erosion is dominant in the annual cropping region (high rainfall zone) and wind erosion is severe in the winter wheat-fallow region (low rainfall zone). It is generally assumed that conservation tillage successfully reduces erosion but also increases herbicide use. In previous decades, agricultural research studies focused on one discipline, was short-term (3yrs or less), and small-scale (miniature plots). In 1985 a long-term, large-scale, inter/multidisciplinary cropping systems study was initiated that ultimately developed an environmentally sound and economically feasible conservation crop production system that managed weeds, was profitable, and improved the sustainability of PNW agriculture. A major factor contributing to the success of that study was the focus on weed management strategies in conservation tillage practices. Additional long-term studies include a 6-yr integrated weed management study for managing jointed goatgrass without in-crop herbicides and an 8-yr no-till spring cropping systems project to control erosion and grass weeds in wheat-fallow. These types of studies have altered significantly the approach for scientists and growers to study cropping systems. There are currently more than a dozen conservation cropping systems studies being conducted in the PNW.
Technical Abstract: The winter wheat production system of the Pacific Northwest is characterized by severe wind and water erosion and winter annual grass weeds with subsequent high herbicide input. Since 1985, numerous multi/interdisciplinary, long-term, large-scale, integrated cropping systems studies have been (or are currently being) conducted. These studies have focused on alternative cropping systems, conservation tillage, fertilizer and herbicide inputs, and weed biology, ecology, and management. The 6-yr integrated pest management project, conducted in the annual cropping zone, showed for the first time that when weeds were adequately managed, conservation crop production systems were more profitable than conventional systems. In the intermediate rainfall zone, a recently concluded 6-yr, three-state study was conducted that integrated single component research results into a multifaceted approach to managing jointed goatgrass. This project has been used as a model study for other western states and the National Jointed Goatgrass Research Initiative. Presently (7 yrs thus far), a study is being conducted in the low rainfall area to examine the feasibility of no-till spring cropping systems in lieu of the highly erosive, weed infested, wheat-fallow system. Because of these projects, the Washington Wheat Commission recognized the importance of long-term, interdisciplinary research and has therefore, established an Endowed Chair at Washington State University for direct seed cropping systems research.