Soils in the range 5.6 to 6.0 are moderately acid and below 5.5 strongly acid. The poor growth of a sensitive crop such as alfalfa may indicate an acid soil condition. However, a soil test is the only reliable way of determining whether soil is acid or not. A lime requirement test should be used to determine the rate of lime to apply. The distribution of acid soils in Alberta is shown in Figure 1.
Acid soils occur most frequently in central Alberta and in the Peace River region.
The proportion of acid soil in an area or soil zone can be misleading for the individual farmer. A farm can have neutral soil even though it is in an area of predominantly acid soils. The opposite can also happen. Pockets of acid soils of 2.5 square kilometres or less can occur in a neutral soil area. Percentage of cultivated acid soils with pH below 6.1 in various areas of Alberta.