pH 

pH is simply the test of the acidity or alkalinity of the soil. The pH scale ranges from 0 to 14, with a pH of 7 being neutral (neither acidic or alkaline). pH measure the hydrogen ion (H⁺) concentration and is expressed in the logarithmic terms (pH = -log (H⁺). This means that as the pH increases the hydrogen ion concentration decrease and since the result is logarithmic each unit change in pH is ten fold (10X). The pH that is recorded is the pH present in the soil solution and not the total pH of the soil.

The pH measurement can be used to evaluate the production potential of the soil. Example, if the pH is low you will low levels of calcium and magnesium, micronutrients that will adversely affect the plant growth. Increased pH will increase the microbial activity within the soil. The ideal pH for plant growth is between 6.0 and 6.5.

In this area of the country the pH of the soil is usually low, due to the amount of pine trees in the area.  

Procedure for test  

1. Fill Test Tube to about 1/3 full with soil sample.
2. From Demineralizer Bottle add demineralized water to about one inch of top of Test Tube. Cap and shake until all the soil is well dispersed.
3. Add 5 drops of Soil Flocculating Reagent, cap and shake.
4. Let soil settled before proceeding to next step.
5. Transfer 1ml of solution to each depression in Spot Plate.
6. In one of the depression add two drops of Duplex Indicator and compare resulting color to Duplex Color Chart.
7. Depending on pH range, choose one of five indicators for a more precise reading.
8. Read resulting color developed from indicator to the indicator’s chart.

Ralph making preparation for a pH test.