2007 Annual Report 1a.Objectives (from AD-416) Determine soybean traits that improve their capability of competing with weeds. Identify soil and cover crop management practices that enhance weed suppression in organic farming systems. 1b.Approach (from AD-416) Cooperate with researchers at USDA-ARS, Beltsville, Rodale Institute, and Penn State University to conduct a broad research program on biologically based weed management. Soybean cultivar experiments will be conducted at USDA-ARS, Beltsville, MD, and at Rodale Institute, Kutztown, PA to evaluate selected germplasm with a range of traits for height and leaf area in weedy, weed-free, and crop-free plots that are managed organically. Detailed studies of mechanisms that enhance weed suppression and crop vigor will be conducted. Novel approaches for integrating competitive cultivars with cover crop and soil management practices will be explored. 3.Progress Report This report documents research conducted under a specific cooperative agreement between ARS and University of Maryland. Additional details of the research can be found in the report for the parent project 1265-22000-164-00D Development of Biologically Based Control Methodologies for Weeds in Agricultural and Natural Areas. Both exploratory and specific glucosinolate analyses are being conducted with LC/MS/MS to determine the compounds present in forage radish and other brassica species. The Brassicaceae tissues analyzed to date contained progoitrin, glucoraphanin, and gluconasturtiin. Glucosinolate concentrations varied between species and tissue types. Progoitrin and glucoraphanin were the major glucosinolates in forage radish. Forage radish shoots had concentrations of glucoraphanin three times greater than roots, and gluconasturtiin was found within root but not shoot tissue. Rapeseed had greater concentrations of both progoitrin and gluconasturtiin than forage radish. As with forage radish, rapeseed roots contained more gluconasturtiin than shoots. Research will be expanded to assay activity of these compounds in soil against weeds and nematodes. A new graduate student was selected and began research in January, 2007, on understanding soil physical and chemical properties on weed emergence and early growth. This project was monitored by meetings on March 6, April 27, June 22, and September 5, 2007, by informal visits in the field, and by email.