A service of Spectrum Analytic Inc

Farms & Agriculture

Sample Requirements

Agronomic Soil Information Form

Material Required

Acceptable Sample Packaging

Paperwork Required

Ship To

Sampling Instructions

Accurate soil analysis with meaningful interpretation requires properly taken samples. Follow all directions carefully and correctly. Sampling technique presents the greatest chance for errors in results. Laboratory analytic work will not improve the accuracy of a sample that does not represent the area.

  1. Select the Proper Equipment

    Collect samples using chrome plated or stainless steel sampling tubes or augers. A clean spade or shovel can also be used. Avoid galvanized, bronze or brass tools. Use clean, plastic buckets. Do not use galvanized or rubber buckets, as they will contaminate the samples. (Figure 1)

  2. When to Take Samples

    Sampling can take place during any period of the year. However, it is best to sample a field at about the same time of year. Wait a minimum of thirty days to sample after applications of fertilizer, lime, or sulfur.

  3. Sample Area

    Samples must be representative of the area you are treating. Most often, sampling by soil color is an acceptable method for dividing large fields into “like” areas. County ASCS aerial photographs can be used as a guide. Areas that differ in slope, drainage, past treatment, etc. should be sampled separately (fig. 2). Sampling across dissimilar soil types is not recommended. And finally, the sample area should be large enough for special lime or fertilizer treatments.

    Always remember to remove any surface debris prior to sampling.

    Do Not Sample:

    • Dead or back furrows.
    • Fence rows, old or new.
    • Old roadbeds, or near limestone gravel roads.
    • Terrace channels.
    • Wind breaks or snow fence lines.
    • Turn-rows.
    • Spill areas.
    • Fertilizer bands including Anhydrous N.
    • Unusual or abnormal spots.

  4. Sample Depth

    Sample TypeDepthNotes
    Conventional Tillage7” Sampling depth must remain constant.
    Strip/Band Fertilization (known) 7” See Figure 4 for instructions.
    Strip/Band Fertilization (unknown) 7” Take 20+ random samples 90° to band rows.
    Reduced Tillage or No-Till 2” and 7” 2” sample is for surface pH determinations.
    Orchards and other trees 7” Take samples inside the “drip line” (Figure 3)
    Lawn/Turf 4” Remove the sod piece from each core sample.
    Pasture 4” Remove the sod piece from each core sample.
    Special Problem Solving 7” and 36” Take 7” sample and 36” sample from the “same hole”
    Pre Sidedress Nitrogen Test 12” Take samples when corn is 10” to 12 “ tall.
    Soil Nitrogen Tests 12” to 36” Drier climate soils require the taking of deeper samples.
    Soybean Cyst Nematode Samples 7” Sample near planted row, in fringe of damaged areas.

    Sampling depth must remain consistent because many soils are stratified and variation in depth will introduce errors into the analytic results.

    To test for soil stratification, sample through the soil profile, separately, 0” to 2”, 2” to 4”, 4” to 6”, and 6” to 8”. Remember to take the recommended number of cores per sample. The greater the difference in the analytic data between samples, the greater the degree of stratification.

  5. Number of Cores and Acres per Sample

    Various studies have shown that proper sampling requires at least 10 core per sample, and sometimes 15 or more cores, depending on the nature of the soil and the size of the area being sampled. A smaller number can introduce variability into the results from different sampling years. There is no rule for the number of acres to include in a single sample. This must depend on the local situation. However, the University of Illinois has long recommended that a single sample should represent no more than 5 acres. Very small sampling areas, such as residential landscape plants and some small gardens may use fewer cores per sample.

  6. Preparing Samples for Shipment

    Thoroughly mix the randomly taken core samples in a plastic bucket and remove a separate, well-mixed composite sample (½ to 1 pint) from the mixture. Place it into the lab’s sample bag, filling it to the “line.” New plastic sandwich bags can be substituted. Make sure to double bag these types of bags. All samples taken for Nitrogen analyses should be immediately air-dried, shipped early in the week, or shipped frozen.

    Once the sample is in the bag, fold the top down to exclude air and roll it down to close and fold the tabs. Write your sample ID designation (include grid sub sample identification where applicable) and your customer’s name on the bag where requested.

  7. Completing the Information Form

    On the Information Form record the same sample, and sub-sample IDs, and the customer name with the address. In the indicated area include your business name and address. Complete all the remaining information as required.

  8. Mailing the Sample

    Spectrum provides the shipping containers (at a nominal fee) but other boxes may be used. A strong envelope may be used when shipping only a few samples.

    Ship to:

    Spectrum Analytic
    1087 Jamison Rd NW
    Washington Court House, OH 43160

Form 1. Sample ID- what you want to name your sample. Label the bag with the same name. This lets us and you know what information belongs to what sample. 2. Crop Code- We base our fertilizer and lime recommendations off the crop you plan to grow. We can provide 3 crop recommendations per sample. 3. Test package- Mark the box with the test you want. There is a description of the tests on the paperwork. Extra tests can be marked as well, either as listed on the form, or you can write on the paperwork that you want a test that isn’t listed. Please call the lab if you have questions about tests we offer. 4. How to sample- We provide illustrations and written instructions on how to sample. You can use our bags, or a sandwich size Ziploc baggie for each sample. We need 1.5-2 cups of soil per sample. Some tests require more soil, or different sampling, but in general, this is what you need. 5. Getting the samples to the lab- If you are close to us, you are welcome to drop samples off in person. We can help you at the front office or you can drop samples around back in receiving. If you are sending samples in the mail, the Post Office has flat rate boxes, or you can use whatever shipping company you prefer. Everyone delivers here to our physical address at the lab. 6. Payment- You can send a check with the paperwork, or include your email address and we will email you an invoice to pay on our website once we finish testing the samples. 7. We have a 1 to 2 business day turnaround on soil samples, once the samples are in the lab. Other things like manure, water, and compost may take a week to process. Please call if you have questions on when a sample will be finished. 8. PLEASE FILL OUT PAPERWORK! The forms are all on the website, under PDF files. If you are unable to print the form, please write your information and what tests you want on a paper that you send with the samples. We want to get your results out correctly and efficiently and having paperwork filled out with your samples is crucial for that.