Updated on 19 October, 2021
Soil testing can refer to one or many of a wide array of soil investigation processes performed for one of many possible reasons. Probably the most widely performed soil tests conducted on a local level are ones done to judge the plant-available trace amounts of plant nutrients, to ascertain fertilizer recommendations for agriculture, and to see if the planting area has adequate topsoil. Other soil testing programs may also be used to analyze the quality of soil, to check the effectiveness of herbicides in controlling weeds, and to locate and evaluate drainage systems. Many state and local governments perform soil quality testing to comply with regulatory requirements. Private organizations that specialize in soil remediation may also perform soil testing programs on your property, for a fee. But which method is right for you?
If you're going to perform a soil test, you'll need a sampling container, a couple of soil samples, a drop cloth or spade, and some testing equipment such as a rototiller or an air compressor. Don't be intimidated if you don't have a lot of money - inexpensive and simple solutions can be just as effective. Just be sure to carefully follow manufacturer's directions for the appropriate sample collection and handling.
First, decide whether you need a soil sample for a soil test or for other plant nutrient analysis projects. Sufficient amounts of most plant nutrients can be detected by simple sampling. You can purchase a soil sampler for under $100. For more sensitive soil samples, such as those containing nitrates or nitrites, you may need to send a soil sample to a lab for analysis. Also, there are specialized soil samplers that will deliver the samples directly to a lab.
If you're not doing a soil test to find nutrient deficiencies, the only way to know what levels are safe for your crops is to get a soil test performed by a local expert. In general, a soil test will determine whether the fertilizer you're applying is sufficient to support plant growth and health. It will also indicate any deficiency in nutrients so that you can make proper fertilization adjustments.
In most cases, the PH level of the soil test specimen is fairly consistent. However, because the pH level of the soil sample may not be completely accurate or vary too much from the surrounding area, the test will provide a range instead of a perfect result. So it's up to you to decide what you think your soil test results indicate. You may wish to have a soil test done if you suspect that you have nutrient deficiencies, but you might be able to correct them without a soil test.
Soil testing doesn't always indicate all-or-nothing results. Sometimes the PH level is too high or too low, or the sample isn't correctly categorized. In these cases, it's good to have an independent lab complete additional testing at your site to determine the proper nutrient specifications for your organic matter and crop structure. If you find that soil testing indicates a possible deficiency, the problem can usually be corrected with proper fertilization.
There are two basic types of soil testing - analytical and differential. The former tests the colloid, soil composition and microorganisms present in a sample. The latter compares samples for pH, nutrient concentrations and compaction. Samples are analyzed using both closed and open methods. Some laboratory services offer analytical soil analysis as well as laboratory testing for other soil components, such as gypsum, silt and clay.
You can purchase professional kits that contain everything needed for a complete Soil Test, or you can conduct a simple Soil Analysis yourself at home. In a nutshell, a proper Soil Analysis determines whether your field soil is in its ideal Ph range, contains the appropriate amount of nutrients needed by plant growth, and has a minimal amount of contamination. Your soil testing report provides important information about your soil condition that can help improve your crop production.