OSU Nematode Testing Service - Sampling

Sampling principles

  • A good sample is the best possible representation of the sample area in the required volume.
  • In fields with discreet areas of symptomatic plants, sample from the edge of the affected area.  Few plant-parasitic nematodes may remain where plant productivity has decreased, while more occur at or ahead of advancing symptoms.
  • 5 acres is the maximum area that should be represented by one sample.
  • Seal sample bags completely to prevent spillage, contamination, and abrasion.
  • Keep samples away from heat and at original moisture content; if adding ice packs for slow transit in hot weather, insulate between sample to prevent sample from freezing. Ship early in the week to avoid weekend delays in transit.

How to sample soil

  • Prepare a composite soil sample from at least 20 locations within the sampling area from the top 12 inches or to the depth of root growth if shallower than 12 inches.  Use a soil sampling tube, a trowel, or a shovel.
  • Thoroughly mix the sample in a bucket or other large container.
  • Take several subsamples from the mixed composite soil sample to obtain about ONE PINT (500 cubic centimeters or one double handful) as the final sample.  A surcharge is assessed for excessively large samples.
  • Place this final sample in a soil sample bag or heavy plastic bag, such as a quart-size freezer bag.  Avoid sandwich bags (too thin).  Make sure that any paper bag you use has a waterproof lining. See below for how to label samples.

How to sample roots

  • Dig subsamples of FINE absorptive* roots from at least 10 locations within the sampling area.  Mix subsamples as appropriate.
  • Take several subsamples from the composite root sample to obtain about ONE PINT (500 cubic centimeters or one double handful) of root material for the final sample. *NOTE: Woody portion of roots and mint rhizomes will be discarded during processing so estimate volume by looking at the amount of fine feeder roots.