Soil pH is also called “soil reaction”. It is the acid-base reaction of the soil solution. Mainly depends on the concentration of hydrogen ions in the soil solution, expressed in pH. A solution with a pH value equal to 7 is a neutral solution; a pH value less than 7 is an acidic reaction; a pH value greater than 7 is an alkaline reaction. Soil pH can generally be divided into the following levels:

pH soil pH

＜4.5 Very strong acid

4.5—5.5 Strong acid

5.5—6.5 Acidity

6.5—7.5 Neutral

7.5—8.5 Alkaline

8.5—9.5 Strong alkaline

＞9.5 Very strong alkaline