Soil Sampling Technique

1. Tools (Equipment)

Use any of the tools shown below, one or two clean pails and soil bags.

Sampling Tools - Ward Labs
Sampling Tools - Ward Labs

2. Sampling Depth

  • Surface soil samples from fields should be taken to a depth of 8".
  • Subsoil samples should be taken from 8" to 36" for residual nitrate. An alternative method would be to sample 8-24" and 24-48".
Sampling Depth - Ward Labs

3. Sample each field separately

If cropping, fertilization and/or liming has not been uniform on a field, then a separate sample should be taken from each management or soil area. If fields are large, you may want to sample 40 acre units separately, but it is not necessary if management has been the same and the soil type is the same. If soil areas within a field are different in appearance (slope, drainage, color or texture), each soil area should be sampled separately. Small areas may not need to be sampled, but they will give some indication of the variation within the field.

Field Sampling - Ward Labs

4. Composite surface soil samples

Composite surface soil samples should consist of a mixture of about 15 soil cores. Composite subsoil samples for the nitrate test should consist of 8-10 cores. Mix these core thoroughly and fill the sample bag. Label the bag correctly and use this same identification on the soil information sheet.

5. Sample separately

Sample separately or avoid such areas as dead furrows, alkali spots and terrace channels.

6. Send

Send samples as quickly as possible. Include soil sample information sheets.

Feed Sampling Procedure


Bales: Sample 20 bales from each cutting or each lot. Core all rectangular bales from the end and all round bales from the twine surface. Mix the samples thoroughly and take a representative sample for analysis using the quartering procedure.

Bales - Ward Labs

Loose Hay Stacks: Select 4 stacks from each cutting for sampling. Collect at least 3 core samples from the side of each stack, mix thoroughly and take a representative sample for analysis using the quartering procedure. If a core sampler is not used for hay sampling, hand grab from each of the bales.

Loose Hay Stacks - Ward Labs


Upright silo: Take random handfuls of silage while unloading. Mix the samples thoroughly and take a representative sample for analysis using the quartering procedure.

Upright Silo Silage - Ward Labs

Horizontal silo: Remove a column 6 inches by 12 inches wide on the open end of the silo. Mix the sample thoroughly and take a representative sample for analysis using the quartering procedure.

Bunk Sample

Take 6-8 grab samples from the bunk(s) as the ration is being unloaded. Mix the sample thoroughly and take a representative sample for analysis using the quartering procedure.

Grain Sample

Take 5 random hand samples from the bin or truck. Mix the sample thoroughly and take a representative sample for analysis using the quartering procedure.

Quartering Procedure

Sometimes when forages are sampled, the total of the aggregate samples is to large and bulky to send in to the laboratory. The total sample size can be properly reduced and still maintain a representative sample by quartering the sample. Mix the entire sample thoroughly, then pour it into a pile on a clean paper or plastic. Then divide the sample into four equal parts (quarters), saving the opposite two quarters. If the sample is still to large, repeat the procedure until the proper sample size of one pint to a quart is obtained. All samples should be placed in an airtight plastic bag and submitted to the laboratory for analysis.

Quarter Procedure - Ward Labs

Manure and Compost Sampling Procedures

Sampling Timing

Due to the volatile organic compounds and ammonium present in manure, samples should be taken within 1 to 2 weeks of application. Composts have already partially decomposed and often contain more stable compounds, so they may be tested 1 to 2 months prior to application.

Sampling Depth and Collection

Because manure compositions can vary greatly between piles due to several factors (animal species, animal feed, bedding time, age of manure), select piles that are most representative of your sample. Collect 8 manure subsamples to a depth of 12” at eight spots throughout the pile. Samples should be moist and contain manure and plants. Compost only requires 6 subsamples due to uniformity. Thoroughly mix subsamples and place in labeled bags. A gallon sized Ziplock bag filled approximately half full is enough.

Storage and Shipping

Samples should be shipped to the laboratory as soon as possible. Keep samples cool (not frozen) until delivery to the laboratory. Place sealed samples in a second or even third plastic bag to prevent spillage and odor. Please clearly mark sample bags with a waterproof pen. The use of felt-tip pens or pencils can smear if exposed to water or during shipping. A sample submittal form is available at for your convenience.

When submitting samples be sure to include your full name, address, phone number, email address if you would like results emailed to you and desired analysis for the samples.

Plant Sampling Procedure

Packaging Guidelines
Tissue samples need to be placed in paper bags and submitted to the laboratory. Plant sample bags are available upon request.

Field Crops Stage of Growth Plant Part to Sample # of Plants
Corn Seedling stage (less than 12") All above ground portion 20-30
Prior to tasseling Top leaf with collar 15-25
Tasseling to early silking Ear leaf 15-25
Soybeans Seedling stage (less than 12") All above ground portion 20-30
Initial flowering Uppermost fully developed trifoliate leaves 20-30
Small Grain Seedling stage (less than 12") All above ground portion 50-100
Boot to heading   20-30
Hay, pasture or forage grasses Just prior to seed head emergence or 4 to 6 weeks after clipping All above ground portion 20-30
Alfalfa Bud stage to 1/10 bloom Upper 1/3 of plant 15-25
Milo Very early heading 2nd leaf from the top 15-25

Stalk Sampling Procedure

Stalk Nitrate Sampling Procedure
  1. Samples should be taken one to three weeks after black layer on 80% of the kernels on most ears.
  2. Cut 8 inches of the stalk 6 inches above the soil surface. See graphic below.
    Stalk Nitrate - Ward Labs
  3. Remove all leaves from the stalk.
  4. Include 10 to 15 stalks from a representative area. Sample areas should be determined based on differences in management or soil type.
  5. Wrap the bundle of stalks in duct tape. Write your name and sample ID on the tape using a permanent marker. The following information should be included on a separate sheet with the samples:

    Physical Address
    Sample ID
    Phone Number

  6. Samples can be mailed to the following address, or dropped off at the lab

    Ward Laboratories, Inc.
    P.O. Box 788
    Kearney, Nebraska 68848

  7. Analysis will be reported in 2-3 business days upon arrival to the lab.

Water Sampling Procedure

  1. Use a clean plastic container for submitting your sample. Bottles can be obtained from the laboratory.
  2. Rinse the container several times with water that is being sampled. Send at least one-half pint of water to be tested.
  3. Wells should be pumped several hours before sampling. Test wells should be sampled after pipe and screen are in place. Pump well for at least 10 hours before sampling.
  4. Samples of lakes, streams, and ponds should be taken from below surface.
  5. If it is not possible to send the sample to the lab immediately after collection, refrigerate until it is sent.

Bacteria Water Sampling Procedure

Please Read Carefully to insure accurate results.

  1. Samples will be accepted MONDAY THROUGH THURSDAY ONLY between the hours of 8 a.m. to 3 p.m.
  2. Samples over 24 hours old will not yield accurate results unless kept in refrigerated condition. Please send as First Class or Priority Mail.
  3. The enclosed sterilized bottle contains a small amount of preservative. If analysis is required in addition to Coliform, a separate sampling bottle is required. (Please request a Water Testing Bottle).
  4. Collect sample from an indoor water tap. Remove screen or strainer from spigot, (if one is present), and sterilize by swabbing with rubbing alcohol. Allow water to run freely for FIVE MINUTES before collecting sample.
  5. Avoid contaminating your sample. Carefully remove lid from enclosed sample bottle without touching the inside of the cap or threaded area of bottle.
  6. Do NOT rinse bottle. Fill bottle to line. Replace lid at once.

If you have any questions please call lab prior to taking sample at 1-308-234-2418.

Liquid Fertilizer Sampling Procedures

A critical requirement in getting a representative sample of a liquid fertilizer is to take the sample directly from the main body of the material without contamination. Avoid, whenever possible, taking samples from lines and valves. Listed below are the preferred points of sampling in order of preference.

  1. Directly from mixing vat.
  2. From the top opening of storage or transport tank after agitating for 15 minutes.
  3. From a delivery or recirculating line after proper recirculation.

Please submit liquid fertilizer in a plastic container.
Bottles can be obtained from the laboratory.