A&L Plains Analytical Laboratories

A & L Plains

Agricultural Laboratories

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Procedures for Taking Good Samples

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SOIL - Procedures for taking good soil samples


Accuracy of the soil test depends on the sample submitted.

• Divide your field into areas, which have the same soil type, color, slope, fertilizer, and crop history.

• Take approximately 15 cores from each uniform soil area. Mix them thoroughly in a clean plastic or paper container. Fill the soil sample bag one-third to one-half full from this representative sample.

• Scrape away surface litter, and sample to plow depth for all row crops. On permanent pastures, sods, lawns, and turf areas, sample four inches deep.

• Several different tools such as a soil sampling tube, soil auger, or spade may be used in taking soil samples. See illustration.

• Label each sample bag with your name and sample identification. The label information should correspond to the sample I.D. listed on the information sheet. A map is printed on the information sheet for your convenience.

• Avoid taking samples from areas such as lime piles, fertilizer spills, gate areas, livestock congregation areas, poorly drained areas, dead furrows, fertilizer bands, old fence rows, or any other unusual area.

• Do not use galvanized, soft steel or brass equipment if trace metal analyses are desired.


How to fill out the information sheet

• Fill in grower's name, sample submitted by, and if charged to a third party list their name.

• List sample identification and check analyses desired.

• If fertility recommendations are requested, list only five samples per page using shaded areas only.

• The accuracy of the fertility recommendations given will depend upon the detail of information supplied.


Packaging and shipping instructions

• If samples are excessively wet, we suggest they be air dried to a workable condition before packaging.

• Place sample bags in a sturdy, spill-proof container and pack tightly to prevent opening and spillage in shipment.

• Place completed information sheet in an envelope and attach to outside of the package.

• Samples should be shipped by United Parcel Service, bus, or air freight.



PLANT TISSUE - Procedures for taking good tissue samples


Collection and preparation of the sample

• Be sure to use a clean container. Never use a metal container as the metal may contaminate the sample.

• Generally, two cups of lightly packed material provides a sufficient amount to conduct an analysis; one cup may be sufficient if gathering petioles.

• If plant samples have soil, dust, fertilizer, or spray residues on them, they will need a light washing, as follows: With the aid of a plastic colander, immerse the sample in cool water containing a couple of drops of PHOSPHATE-FREE detergent, and gently agitate for no longer than about 10 seconds. Extended washing may damage the plant tissue and remove some of the soluble nutrients.

• Remove the colander and quickly rinse the sample under flowing pure water. Blot-dry with a clean towel.

• Either air-dry samples for one day (below 176 degrees F) or ship as soon as possible in perforated bags to allow air movement and a degree of drying in transit.

• Never send fresh samples in sealed plastic bags unless kept cool.

• Never freeze samples.

• Do not include roots with samples for nutrient analysis unless required.

• Specific sampling procedures are required for disease diagnosis. Therefore, please contact us for instructions before sampling.


Sampling Locations: When and where to sample


Before taking tissue samples ensure that timing and location of samples correlates with interpretive data. Instructions for petiole and leaf sampling may differ. Also, comparing samples from both a "good" and a "bad" area often helps in determining corrective action. If specific sampling guidelines are not given, collect recently mature leaves just below the growing point from at least 10 plants. A partial sampling guide follows, although many variations exist. Refer to the A&L Agronomy Handbook or contact us for further information.




Free tissue sample mailing supplies


A & L Plains Agricultural Laboratories will provide suitable plant tissue sample bags, as well as plant tissue submittal forms at no charge on request. (You may also download submittal forms from this website.)


The information you receive on our reports is as accurate as the information submitted with your sample. Please fill out all submittal forms as accurately, completely and legibly as possible.


LIVESTOCK NUTRITION - Procedures for taking good feed samples


Silage/high moisture grain/haylage/fresh forage


These materials can be sampled at harvest if moisture content is low enough to prevent seepage. Corn silage at dent stage or beyond should not seep. If seepage is expected, wait until seepage has stopped or take sample as it is being fed.

• Sampling at harvest - collect silage in a large plastic bucket from several loads by taking random handfuls. Mix thoroughly and fill plastic sample bag from this composite. Seal and send immediately or freeze sample and send to the lab.

• Sampling after ensiling - secure random handfuls of silage from at least 10 different spots over the exposed surface area of the silage.


Sampling hay

• Hay may be sampled, as it is stored, if it is dry enough to keep without further curing. Different cuttings should be sampled separately unless fed at the same time.

• Hay samples should be taken with a core sampler if possible. At least 12 cores of hay should be taken from random bales or locations if loose or chopped.


Sampling grains and concentrates

• Take random handfuls from several locations in the pile. Ear corn should be ground before attempting to take sample.


Information sheet

• Fill out a feed information sheet indicating test(s) desired. Report of most analyses will be sent within 3 days after samples are received in our laboratory.


IRRIGATION WATER - Proper sampling procedures


Proper sampling is a must in obtaining a representative water sample. Irrigation water samples should not be collected until after the well has pumped for a period of one to two hours, or until the water has cleared up. Stream, pond, and catch pit samples should be taken during the period of time when they are being used for irrigation or a water source of livestock. It may be necessary to collect several samples during the season to correlate to evaporation and dilution.


Sample size


A 16-ounce sample is usually sufficient for most quality and nutrient analysis.


General guidelines

• Clean plastic containers can be used for most regular analysis. However, for samples, which are to be checked for the presence of organic residues or bacteria, a separate sterile container must be used. Contact our lab for specific instructions.

• If shipped to the lab, be sure container used seals completely.

• Ship or bring sample(s) to the lab as soon as possible after collection.


PLANT DISEASE - Sample collection instructions


An effective control recommendation is dependent upon a rapid and accurate diagnosis of the plant disease or disorder. A rapid and accurate diagnosis is dependent, in turn, upon the quality of the sample collected. Since the grower (and/or employee) collects and submits the sample, he/she contributes significantly to the fate of the affected crop. The following guidelines will aid in collecting plant samples satisfactory for diagnostic work.


• Observe carefully the affected plants and collect plants that exhibit various stages of seriousness of the disease or disorder. For example, collect entire plants in various stages of wilt or leaves with leaf spots that show various stages of brownness.

• Collect plants from the center, middle and margins of an affected area of plants and keep the collections separate. This is especially important for turfgrass samples.

• Collect entire plants if practical. Often leaf or stem symptoms are caused by problems in the root system. If the root system is not included in the sample, the cause cannot be determined.

• If a disease or disorder obviously affects only a particular part of the plant (e.g. leaves, stems, fruits), collect only that particular part, but include several specimens, not just one.

• For entire plants (especially turf grass) retain the soil or potting mix around the root system.

• Fill out the Plant Disease Identification Form as completely as possible. This form is provided at the back of this fee schedule to use or photocopy when submitting samples. Additional forms are provided by the lab at no charge.

Packing Instructions


A plant collection satisfactory for diagnosis may deteriorate beyond usefulness during shipment if the collection is packed incorrectly. The following guidelines will aid in packing plant collections for shipment.


• For entire plants retain the root system with soil in the container, if container grown; otherwise, place the root system with soil in a plastic bag and seal the bag around the main stem of    the plant.

• For young rooted plants, wrap moist paper towels or cloth around the rooted end prior to packing.

• For plant parts (e.g. leaves, stems, fruits), place samples in paper bags. It may be desirable to press leaves flat between two pieces of cardboard. The leaves will arrive in satisfactory condition for diagnosis of most leaf spots. NEVER moisten the above ground parts, particularly the leaves, and then place them in a plastic bag prior to shipment. For plants suspected of having a virus disease, entire plants exhibiting leaf symptoms in various stages

are desirable.

• Tag each sample and include the completed Plant Disease Identification Form or information in a letter (preferably in a protective plastic bag) in the shipping box. Send packaged samples as soon as possible after collection and by the fastest

means reasonable

Learn more about the best sampling procedures for your soil, feed, water, and more.

Make sure that you take great care when sending in your samples.

Proper shipping methods will help preserve your sample for testing.

Best Sampling Procedures

When taking a sample of any kind, there are methods and procedures that will lessen the chance of accidental contamination or that the sample is compromised in some way. We can only report on the information derived from what we receive. Listed below are instructions on steps you can take to ensure that your sample is both representative of the whole, and that it does not contain unwanted materials that will result in a distorted reporting of actual variables. (Quick links are provided below)


If you have further questions or would like additional clarification, please contact either our local associate in your area or our lab. Thank you.

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