Subject
- Drainage -- Oregon -- Willamette River Valley2
- Soil moisture -- Oregon -- Willamette River Valley2
- Soils -- Oregon -- Willamette River Valley2
- Waterlogging (Soils) -- Oregon -- Willamette River Valley2
- Acid soils -- Oregon -- Willamette River Valley1
- Alfalfa -- Oregon -- Willamette River Valley1
- Codling moth -- Control -- Oregon -- Willamette River Valley1
- Farm management -- Oregon1
- Farms -- Oregon -- Willamette River Valley1
- Hay -- Economic aspects -- Oregon -- Willamette River Valley1
- Irrigation -- Economic aspects -- Oregon -- Willamette River Valley1
- Irrigation -- Oregon -- Willamette River Valley1
- Irrigation pumps1
- Kale -- Economic aspects -- Oregon -- Willamette River Valley1
- Ladino clover -- Oregon -- Willamette River Valley1
- Silage -- Economic aspects -- Oregon -- Willamette River Valley1
- Soil biology -- Oregon -- Willamette River Valley1
- Soil surveys -- Oregon -- Willamette River Valley1
- Strawberries -- Economic aspects -- Oregon -- Willamette River Valley1
- Strawberries -- Oregon -- Willamette River Valley1