Soil Gravimetric water content SOP

This procedure is meant to measure the gravimetric water content of a fresh soil sample (or potentially from a frozen sample).

1. Before subsampling make sure your fresh soil is well homogenized.

2. Use a set of aluminum dishes/tins with unique numbers on tabs (1-x) (label using sharpie, NOT labeling tape).

3. Weigh your empty dish/tin and record weight (which is “empty dish/tin” and should be ~1 g).

4. Add ~5 gram fresh soil into dish/tin and record weight (which is “dish/tin weight + fresh soil”).

5. Place tins in drying oven to be dried at 105 degrees Celcius for 24 hours or 65 C for 48 hours (if soil is high in organic matter).

6. Weigh Oven dried sample and record weight (which is “dish/tin weight + OD soil”).

7. If sample was not sieved in the field or prior to drying, sieve sample through 2mm sieve for gravel content. Be sure to push soil through sieve. Dried soil may feel like a rock but will break up with a little force. Gravel content is weighed and recorded.