Soil testing is the only tool we have to evaluate the pH, phosphorus (P), and potassium (K) status of the soil. Knowing this information allows growers to make economically optimum applications of lime and phosphorus and potash fertilizer. In these times of economic uncertainty, managing input costs is an important component of farm sustainability. Many growers have opted to cut costs by eliminating soil testing as part of their management program. This is not a recommended strategy.
University of Wisconsin Video - Soil Sampling Basics