The purpose of this project was to examine potential benefits of cover crops for mature hazelnut orchards in the Willamette Valley, Oregon where 99% of the US hazelnut crop is produced. Summers are dry but winters are characterized by intense precipitation and are very wet (40-50 in precipitation annually). Currently, maintenance of a bare orchard floor is the common practice to facilitate efficient mechanical harvest of nuts from the orchard floor where the nuts drop naturally when they are mature. Erosion and nutrient leaching are major concerns during the wet winter season in bare ground orchards with any kind of slope.