The scale that measures the acidity or alkalinity of soil is called the pH scale.

Here's a breakdown:

* pH stands for "potential of hydrogen."

* The scale ranges from 0 to 14.

* A pH of 7 is neutral.

* Values below 7 are acidic. The lower the number, the more acidic the soil.

* Values above 7 are alkaline (also called basic). The higher the number, the more alkaline the soil.