Soil test

Soil testing

Soil testing is often performed by commercial labs that offer a variety of tests targeting groups of compounds and minerals. There may be some advantage to using a local lab that is familiar with the chemistry of the soil in the area where the sample was taken. This enables technicians to recommend the tests most likely to reveal useful information.

Laboratory tests often check for plant nutrients in 3 categories:

• Major nutrients: nitrogen (N), phosphorus (P), and potassium (K)


• Secondary nutrients: secondary nutrients - sulphur, calcium, magnesium


• Minor nutrients: iron, manganese, copper, zinc, boron, molybdenum, aluminum.

Do-it-yourself kits usually only test for the three "major nutrients" and for soil acidity or pH level. Do-it-yourself kits are often sold at farming cooperatives, university labs, private labs, and some hardware and gardening stores. Electrical meters that measure pH, water content, and sometimes nutrient content of the soil are also available at many hardware stores. Laboratory tests are more accurate than tests with do-it-yourself kits and electrical meters. Here is an example soil sample report from one laboratory.

Soil testing is used to facilitate fertilizer composition and dosage selection for land employed in both agricultural and horticultural industries.

Prepaid mail-in kits for soil and ground water testing are available to facilitate the packaging and delivery of samples to a laboratory. Similarly, in 2004, laboratories began providing fertilizer recommendations along with the soil composition report.

Lab tests are more accurate, though both types are useful. In addition, lab tests frequently include professional interpretation of results and recommendations. Always refer to all proviso statements included in a lab report - these may outline any anomalies, exceptions and shortcomings in the sampling and/or analytical process/results.

Lead is a particularly dangerous soil component. The following table from UMinn categorizes typical soil concentration levels and their associated health risks.