Soil

The preparation of soil samples for DNA extraction using Qiagen MagAttract® PowerSoil® Pro DNA Kit.

Thawing frozen soil samples

Pooling individual soil core samples:

1. Take the soil cores out of the freezer and let them thaw at room temperature.

2. If the samples were not homogenised in the field, then prior freezing, proceed with pooling the samples:

   2.1. once the soil samples from the same site (and depth) are thawed, transfer each sample to a sterile zip-lock plastic bag.

   2.2. Close the bag and thoroughly homogenise the pooled sample.

3. Weigh maximum of 250 mg (~100 mg for organic rich sample) of the soil mixture to a 2 mL tube (can be PowerBead Pro Tube from the kit).

Important

Do not freeze the samples again, proceed directly to the DNA extraction.

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Oven drying

1. After collection or after thawing and pooling (if soil samples were frozen in individual containers), transfer soil into a clean paper bag and active thaw/dry the samples in an oven at ~37ºC.

2. When the soil is dry, then homogenise the soil sample by for example transferring soil to a sterile zip-lock plastic bag that is reinforced with the tape on the sides and crush the soil in between the hands into fine soil powder.

3. Weigh maximum of 250 mg (~100 mg for organic rich sample) of the soil powder to a 2 mL tube (can be PowerBead Pro Tube from the kit). Tubes with dry soil samples can be stored at room temperatue until further steps. Or proceed immediately with the DNA extraction.

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BGE case study

The soil sample handling SOP within BGE’s case study “Characterization of Prokaryotic and Eukaryotic Biodiversity from Soil Samples” is available in WorkflowHub (which hosts the downloadable PDF).

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