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Soil testing provides producers and homeowners with important information about soil fertility. This information can help produce better crops and reduce costs by guiding management decisions like the type and amount of fertilizers to apply.
If you plan to collect your own soil samples and submit them to the K-State Soil Testing Laboratory, use the following guidelines for collection, handling, and shipping. For more background on how to obtain a representative soil sample, see the companion article in this eUpdate.
Preparing to sample
- Gather the right tools: a probe, auger, or spade, and a clean plastic or metal pail that have not been used for feed, fertilizer, or other organic products. These can leave residues and affect the soil samples.
- If testing for zinc, use a plastic container only to avoid contamination from galvanized buckets or rubber materials.
- Obtain soil sample bags and an information sheet from your local Extension office or fertilizer dealer. Soil bags can also be ordered online through K-State Research and Extension at https://www.bookstore.ksre.k-state.edu/Item.aspx?catId=298&pubId=6719
Collecting soil samples
- On the information sheet, sketch a simple map of your field. Divide fields into areas that share the same soil texture, color, slope, and cropping/fertilization history.
- From each uniform area, collect 20–30 cores or slices (minimum 12–15). Mix thoroughly in a clean container and transfer to the sample bag.
- For most tests, collect cores from the top 6 inches of soil.
- For available nitrogen, chloride, or sulfur tests, a subsoil sample to a depth of 24 inches is necessary.
- On long-term reduced tillage or no-till fields, a split sample from the top 6 inches (i.e., 0 to 3 inches and 3 to 6 inches) is encouraged to assess pH and nutrient stratification near the surface.
- Avoid sampling in unusual areas such as fencerows, dead furrows, low spots, or livestock feeding areas, unless you want information about those spots specifically, then submit a separate sample.
Handling and storing samples
- Label each sample bag clearly and record the number on both the bag and the information sheet.
- If same-day submission is not possible, refrigerate samples at 40 °F or less, or air-dry before shipment. (See the companion article, Soil sample handling practices can affect soil nitrate test accuracy.)
- If air-drying samples, start the process as soon as possible, especially for available nitrogen tests. Open the sample bags and place them in a temperature and humidity-controlled place with good air movement so moisture can evaporate quickly. Do not use heat for drying and also protect the samples from freezing for best results.
Submitting to the laboratory
- Fill out the information sheet completely. It’s important to fill out as much information as possible for the most accurate recommendations from the submitted soil samples.
- Deliver samples to your local Extension office for shipping, or ship them directly to the Soil Testing Lab using next-day delivery if at all possible.
- If mailing directly, place samples in a sturdy container include completed information sheets. Next-day shipping labels with UPS can be printed from the Soil Testing Lab website.
Mailing address:
Soil Testing Laboratory
2308 Throckmorton PSC
1712 Claflin Road
Manhattan, KS 66506-5503
Additional resources
For a full list of analysis options and costs, visit the Soil Testing Lab website: www.agronomy.k-state.edu/outreach-and-services/soil-testing-lab
You can also contact the lab by email at soiltesting@ksu.edu and by phone at 785-532-7897.
See the K-State publication MF-734 “Soil Testing Laboratory Information” at: https://www.bookstore.ksre.k-state.edu/pubs/MF734.pdf.
Dorivar Ruiz Diaz, Nutrient Management Extension Specialist
ruizdiaz@ksu.edu
Bryan Rutter, Soil Testing Lab Manager
rutter@ksu.edu
Peter Tomlinson, Environmental Quality Extension Specialist
ptomlin@ksu.edu
Tina Sullivan, Northeast Area Agronomist
tsullivan@ksu.edu
Tags:
soil sampling Soil Testing Lab soil fertility fall soil sampling