- Plants, Effect of herbicides on18
- Plants, Effect of nitrogen on16
- Plants, Effect of light on11
- Plants, Effect of soil moisture on11
- Plants, Effect of temperature on11
- Food -- Effect of radiation on9
- Douglas fir6
- Plants, Effect of cold on6
- Nitrogen fertilizers5
- Semiconductors -- Effect of radiation on5
- Soil temperature5
- Vegetable gardening -- Oregon5
- Plant competition4
- Plants -- Effect of nitrogen on4
- Plants, Effect of boron on4
- Plants, Effect of glyphosate on4
- Plants, Effect of nitrates on4
- Plants, Effect of potassium on4
- Plants, Effect of soil compaction on4
- Plants, Effect of ultraviolet radiation on4