Soil test

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In agriculture, a soil test is the analysis of a soil sample to determine nutrient content, composition and other characteristics. Tests are usually performed to measure fertility and indicate deficiencies that need to be remedied.

1 Soil sampling
2 Storage and handling
3 Soil testing
4 See also
5 References

[edit] Soil sampling

The quality of the original soil sample plays a key role in determining the practical value of test results. Soil characteristics can vary significantly from one spot to another, even in a small garden or field. Sample depth is also an important factor. And the presence of various nutrients and other soil components varies during the year, so sample timing may also be important. Mixing soil from several locations to create an "average" sample is a common procedure. All of these considerations affect the interpretation of test results.

[edit] Storage and handling

Because certain characteristics of soil change with time it is essential that soil is analysed as soon as practical. If it can not be tested within 24 hours of sampling soil should be frozen to reduce changes due to biological and chemical activity. Longer periods between sampling and testing may require the soil to be air dried. Properly dried soil may be stable for periods of 6 months or more.

[edit] Soil testing

Soil testing is often performed by commercial labs that offer an extensive array of specific tests. Tests include, but aren't limited to, major nutrients - nitrogen (N), phosphorus (P), and potassium (K), secondary nutrients - sulfur, calcium, magnesium, minor nutrients - iron, manganese, copper, zinc, boron, molybdenum, aluminum, physical properties - soil acidity, electrical conductivity, soil organic matter, moisture content.

Less comprehensive do-it-yourself kits are also available, usually with tests for three important plant nutrients - nitrogen (N), phosphorus (P), and potassium (K) - and for soil acidity (pH). Lab tests are more accurate, though both types are useful. In addition, lab test frequently include professional interpertation of results and recommendations.