Importance

Soil pH is a measure of its acidity or alkalinity and is an important property because of its influence on the supply of nutrients (cations and anions) to plants, the chemical behaviour of toxic elements and the activity of microorganisms. There are two standard laboratory tests; using water (pH H₂O) and using 0.01M calcium chloride (pH CaCl₂), both of which use a 1:5 soil to solution ratio. Because these two methods give different values, we suggest using pH H₂O.

Assessment

Assessing pH has to be carried out with a pH kit.

Scoring

Good condition: Score 2

5.5 – 7.5

Moderate condition: Score 1

< 5.5 or > 7.5

Poor condition: Score 0

< 4.5 or > 8

References

http://www.blm.gov/wo/st/en/prog/more/soil2/soil2/indicators.html  (Adapted)