Soil Sampling Protocol

There is no theoretical maximum to the area of land that can be covered by 1 soil microbiology test.

 

Assuming that the plant succession is the same, the topography is the same, and the land is relatively homogenous, any sized land can be assessed, microbiologically speaking, using one soil microbiology assessment.

 

For each field, piece of land, or area in question:

 

 

  1. If you have a specific crop or set of plants (annuals or perennials) that you are interested in, take soil cores from halfway between the base of the plant and the drip line of the plant. For smaller annual plants, this location will be close to the base of the plant.
  2. Grid off the land, either mentally or on a digital map. If the area in question is being sectioned into a grid for the selection of areas for sampling, the maximum size of land that can be sampled in one “space” of that grid is 1 acre. In other words, each space of the grid can be a maximum of 1 acre in size.
  3. Randomly select at least 40% of the grid spaces (using a random number generator) to sample from. If desired for future reference and/or testing, mark the areas you are sampling on a map or get GPS coordinates of each sampling area.
  4. Take 3 soil cores (using an apple corer, soil corer, hand trowel, shovel, etc.) from around a random plant within each grid space chosen.
  5. Take samples and hand over or mail priority (3 days or less) the same day that samples were taken, if possible

Below are some more details about sampling protocol:

  • Avoid going right to the boundary of the field and to any areas that are not representative of the field (e.g. the ridge line or a depression or a patch of plants that is not representative of the whole). The exception to this is if you are specifically wanting to know about those unrepresentative areas. Then, you would only sample those areas for a given soil biology test. If desired, mark the areas you are sampling per test on a map so that you can be sure to randomly sample those same areas individually in the future.
  • Each soil core only needs to be 3” deep and ½” in diameter.

 

  • Place all of the soil cores for one soil test into the same bag. No need to mix the samples as that will be done in the lab before samples are analyzed. (Note: Especially for larger fields being sampled, to reduce the amount of sample material sent to the lab, you may combine and thoroughly mix the sample material separately. Do the mixing in a sterile container and then place a smaller amount of the mixture in the sandwich bag or other vessel that will go to the lab).

 

  • For any single sample, please ensure that you do not fill the bag more than 1/2 full with material. Seal the bag and leave a small part of the edge of the top unsealed (open to the air) – do not expel the air from the bag, as this will limit the oxygen available to the biology in the sample which may result in anaerobic conditions being formed. If mailing the sample, seal the bag but leave as much air in the bag as possible. Also, please do not put any identifying information about your sample on a piece of paper and place it inside the bag. The paper could potentially change the biology of your sample. All sample bags should be labeled with the name of the sample and date the sample was taken out of the ground on the outside. Store the sample in conditions as close to those that it came from as possible before handing it over or mailing it (dark location, similar ambient temp., etc).

 

  • You must repeat the sampling protocol for each individual field or paddock you want to know the biology of if the fields have different conditions, different plants, different management practices, etc. Use different sample bags for each soil test.