Soil pH

Soil pH is a measure of the acidity or basicity (alkalinity) of a soil. Soil pH is a key characteristic that can be used to make informative analysis both qualitative and quantitatively regarding soil characteristics. pH is defined as the negative logarithm (base 10) of the activity of hydronium ions in a solution.

In soils, it is measured in a slurry of soil mixed with water, and normally falls between 3 and 10, with 7 being neutral.
Acidic soils have a pH below 7 and alkaline soils have a pH above 7.
Ultra-acidic soils and very strongly alkaline soils are rare.

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