Subject
- Spraying and dusting in agriculture -- Oregon -- Willamette River Valley44
- Pesticides -- Application -- Oregon -- Willamette River Valley41
- Soils -- Oregon -- Willamette River Valley17
- Pear -- Diseases and pests -- Control -- Oregon -- Willamette River Valley10
- Water resources development -- Oregon -- Willamette River Valley10
- Apples -- Diseases and pests -- Control -- Oregon -- Willamette River Valley9
- Viticulture -- Oregon -- Willamette River Valley9
- Blueberries -- Diseases and pests -- Control -- Oregon -- Willamette River Valley8
- Cherry -- Diseases and pests -- Control -- Oregon -- Willamette River Valley8
- Soil conservation -- Oregon -- Willamette River Valley8
- Upper Willamette Resource Conservation and Development Project8
- Eastern filbert blight -- Control -- Oregon -- Willamette River Valley7
- Hazelnuts -- Diseases and pests -- Control -- Oregon -- Willamette River Valley7
- Walnut -- Diseases and pests -- Control -- Oregon -- Willamette River Valley7
- Cherry -- Diseases and pests -- Integrated control -- Oregon -- Willamette River Valley6
- Cover crops -- Oregon -- Willamette River Valley6
- Groundwater -- Pollution -- Oregon -- Willamette River Valley6
- Irrigation -- Oregon -- Willamette River Valley6
- Nitrates -- Environmental aspects -- Oregon -- Willamette River Valley6
- Wetland ecology -- Oregon -- Willamette River Valley6