Soil Acidity and Liming

Part 1, Section 2: Soil Fertility Management

Soil Fertility Management

SOIL ACIDITY AND LIMING

Liming an acid soil is the first step in creating favorable soil conditions for productive plant growth. Crops vary in their ability to tolerate an acidic (low pH) soil. In addition, evidence has shown that soil acidity may influence other crop management problems such as herbicide activity. Soil pH is a good indicator of the need for liming, but a buffer pH measurement is necessary to determine the quantity of soil acidity to be neutralized in order to change the soil pH. The general goal of liming agricultural soils continues to be a soil pH of 6.0 to 7.0.

Raising soil pH requires a quantity of agricultural liming material that is determined by the amount of acidity in the soil and the quality of the liming material. Soil acidity is measured by soil testing; the quality of agricultural liming material is determined by its purity and particle size distribution. In Pennsylvania, agricultural liming materials must, by law, meet minimum quality standards.