Standard operating procedure for soil pH determination

FAO

Standard operating procedure for soil pH determination

Year of publication 2021

Place of publication Rome, Italy ;

Pages 23 p.

Author FAO

Publisher FAO ;

Product type Booklet

Edition 1

Full item page

Synopsis (short abstract) Soils are referred to as being acid, neutral, or alkaline, depending on their pH, with 7 being neutral, below 7 acidic and above 7 alkaline. The pH range normally found in soils varies from 3 to 9. As pH is measured in terms of hydrogen ion activity, pH is thus a measure of only the intensity of H+ activity and not the amount of acidity present. The desirable soil pH range for optimum plant growth varies among crops. Generally, a soil pH between 6.0-7.5 is acceptable for most plants, as most nutrients are available in this pH range. However, some plants have soil pH requirements above or below this range. An acidic pH may cause higher mobility of toxic elements potentially leaching into ground water or taken up and accumulated in plants. Additionally, inhibited plant growth may be observed in low pH soils due to aluminum toxicity. In higher pH soils, phosphorus and most micronutrients may become less available. As the pH value of many soils correlates with base saturation, it may also be used in the field for preliminary classification purposes.

Cite this content as:

FAO. 2021. Standard operating procedure for soil pH determination. Rome.

Language English

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