- Soft wheat -- Varieties -- Northwest, Pacific5
- Winter wheat -- Varieties -- Northwest, Pacific5
- Herbicide-resistant crops -- Northwest, Pacific3
- Landslides -- Oregon3
- Nitrogen fertilizers3
- Reforestation -- Oregon3
- Vegetable gardening -- Oregon3
- Airplanes -- Wings -- Design and construction2
- Grass seed industry -- Oregon, Eastern2
- Lumber trade -- Oregon2
- Rainier, Mount (Wash.)2
- Ryegrasses -- Fertilizers -- Oregon, Western2
- Soft wheat -- Disease and pest resistance -- Northwest, Pacific2
- Stoneflies2
- Water -- Pollution2
- Winter wheat -- Disease and pest resistance -- Northwest, Pacific2
- Winter wheat -- Varieties -- Oregon, Eastern2
- Winter wheat -- Varieties -- Washington (State), Eastern2
- Wooden beams -- Mechanical properties2
- 4-H clubs1