Soil Acidity in Oregon
Declining soil pH is often overlooked because symptoms do not appear, and crop yield does not significantly decline, until a soil pH threshold is reached. Once soil pH drops below the crop threshold, a very small difference in soil pH can result in a substantial yield decrease (Figure 3). This situation differs greatly from a slight nutrient deficiency, which might cause only a 10 or 15 percent yield reduction. When soil pH is a few tenths of a unit lower than a crop’s threshold, yield can decrease 50 percent or more.