Part 1, Section 2: Soil Fertility Management
Soil Fertility Management
SOIL TESTING
Recommendations
Analysis
The soil testing procedures currently used by the Penn State soil testing program are listed below and on the report.
| Test | Method |
|---|---|
| Soil pH | Water |
| Acidity | Mehlich Buffer |
| Phosphorus | Mehlich 3 |
| Potassium | Mehlich 3 |
| Magnesium | Mehlich 3 |
| Calcium | Mehlich 3 |
This information is useful if you compare analytical results from different labs. Direct comparisons can be made only between labs using exactly the same procedures. There are many different methods in use around the country, each containing both strong and weak points. Which test will be used in a given area is based on research to determine how well the test works under local conditions. The tests used by the Agricultural Analytical Services Lab at Penn State have been determined to work best for Pennsylvania conditions. Note that the Bray 1 extractable phosphorus and neutral 1 N ammonium acetate extractable potassium, calcium, and magnesium tests used at Penn State before 1991 are very similar to the Mehlich 3 extractable amounts of these nutrients. Note that some state regulations, such as the Pennsylvania Nutrient Management Law, require soil tests to follow the recommended procedures in the list above.