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Soils Processing Users Guide



Prior to initiation of the experiment, soil cores will be collected during the growing season from all of the plots. For each plot, collect two to three soil cores (soil corer - 2.5 x 10 cm) from each of the 2.5 x 2.5 m subplots (in areas designated for destructive biomass sampling). Litter and vegetation should be removed from the soil surface before collecting each sample. Composite and homogenize these sub-samples into a single sample for each 5x5 m plot (total of 30 samples that weigh roughly 500 g each). Please note, we need an absolute minimum of 105g but around 200g is better. 500g is preferred. All soil samples should be double bagged in paper and allowed to air dry. Label each bag (with permanent marker, Sharpie preferred) with the following information: date of collection, name of collector, name of sampling site, and block/plot/treatment identification.


1. Ensure the samples have air dried completely (in paper bags).

2. You MUST run each sample through a 2mm sieve to remove rocks, plant root fragments, break up large clumps of hardened soil, etc. Sending un-processed soil can lead to potential legal permitting issues because the US Department of Agriculture restricts the acceptance of plant materials (roots) and arthropods in our lab, especially from international locations.

2mm sieve and unsaved soil before it is pushed throughSieved soil (we want this); Rocks and roots that do not pass through sieve (do not send this)

3. Ensure each sample bag is labeled with the date of collection, collector, site, block, and plot. Then please follow instructions below to ship to University of Minnesota.

How to label paper bag


Please follow these instructions exactly. Our permit is very specific about how soils should be shipped and handled.

1. Must be shipped by a bonded carrier (i.e. UPS or FedEx) to exactly this address:
Dr. Sarah Hobbie
University of Minnesota - Twin Cities 140 Gortner Laboratory
1479 Gortner Avenue Saint Paul, MN 55108 USA

2. Dried, sieved soil must be shipped in a "securely closed, watertight container (primary container) which should be enclosed in a second durable watertight container (secondary container)". Please pay close attention to these guidelines! Securely closed zip-top bags are acceptable watertight containers. Double-check that individual samples are labeled with site, block, plot, and date of collection.

Paper bag (sample bag) inside of plastic bag (primary container) Plastic bag (primary container, 1) inside of a larger plastic bag (secondary container, 2)

3. Attach a PPQ form 550 [email to request] to the *exterior* of each shipment box.

4. Include a copy of the soil permit [email to request] *inside* each shipment box.

5. The *outside* of the box should be labeled “contents: USDA regulated soil samples”

6. If you have records for the shipment (weights, general composition), please include those as well.

7. Upon shipment, please notify Ashley Asmus (aasmus at umn dot edu) and Anita Porath-Krause (aporathk at umn dot edu) of the expected arrival date of the soils, as well as any other necessary information about the shipment.