Sampling your soil for better soil test results
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Editor’s note: This article is from the archives of the MSU Crop Advisory Team
Alerts. Check the label of any pesticide referenced to ensure your use is
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Sampling your soils to determine soil pH and soil nutrient levels is an
excellent management tool that aids in determining not only liming
requirements, but also your fertilizer needs.
Soil sampling may be conducted any time of the year with a few
exceptions. First, sampling should be done prior to lime or fertilizer
applications as these nutrient inputs will directly affect the accuracy
of your testing results. If either lime or fertilizer has been applied,
wait a period of time to allow for the nutrient applications to
equilibrate in the soil before sampling and testing.
The frequency in which you should sample your soils also varies
depending on factors such as the crops grown, crop rotations, nutrient
inputs and removals, soil texture and a pre-existing soil test history. A
general rule of thumb when it comes to soil sampling frequency is to
follow your crop rotation frequency. For example, if you have a
three-year crop rotation, sample your soils every three years. If you
have a four-year crop rotation, sample every four years. Remember, the
more consistent you are in following your crop rotation frequency and
taking samples during the same time each year, the more comparable the
soil test results will be.
When it comes to taking your soil sample, the key is to obtain a sample
that is representative of the area. For traditional soil sampling, a
single sample should represent no more than 20 acres. Each soil sample
should comprise of at least 15 to 20 soil cores to a depth of 8 inches
which have been collected from the field in a random zig-zag fashion. If
you have a large field, you will need to take multiple soil samples
that represent a portion of the field. Splitting your field according to
good versus bad production areas, old use patterns, soil types, and
other influential factors will yield more representative soil test
samples.
Additionally, there are other soil sampling strategies that are more
intensive than traditional sampling, such as using GPS technology
