- Oregon State University researchers are expanding their study of mineral nutrition in winegrapes as part of a project sponsored by the Wine Advisory Board. Further research is justified because of increasing grower interest in nutritional factors that affect production and quality. Winegrape growers utilize Oregon State University's Plant Analysis Laboratory to an extent far greater than winegrape acreage would suggest. The industry currently ranks third in sample volume behind filberts and sweet cherries. Winegrapes deserve more attention. The goal of the new project is to develop better diagnostic services. Over the past two years, Dr. John Baham of the Department of Soil Science has been evaluating potassium fertility programs and reviewing historical plant and soil mineral analysis data from records dating back to 1975. His initial observations suggest that improvement in diagnostic services is possible. The value of petiole vs. leaf analysis is not fully resolved. Standards developed for other areas are a valuable starting point, but they could be fine tuned for the specific needs of our winegrape industry. The problem of defining optimum nutrition with regard to both yield and quality needs to be addressed.