Perhaps the most significant single measurement of a soil's ability to adequately support plant growth is a pH determination. If soils are too acid, reduced nutrient availability of all the macronutrients will result. Conversely with several of the micronutrients, low soil pH can increase solubilities, even to the point of causing plant toxicity. Aluminum, an element regarded as nonessential for plant growth, has been shown by numerous workers to produce toxic plant effects at low soil pH (1). High soil pH likewise is undesirable for plant growth and can result in reduced availability of several micronutrients such as boron, zinc, iron, and manganese. Phosphate fixation can occur when excessive calcium is present. Therefore, the majority of agronomic plants do best when grown in neutral to slightly acid soils in the 6 to 7 pH range