*Rationale:*

A soil sample is made up of soil, water, air, and, sometimes rocks. To
correctly scale soil components (e.g., percent carbon) to an ecosystem
level (e.g., grams of carbon within each m^2^), we must know the amount
(or mass) of soil only occupying a specific amount of space (or volume).
This value is soil bulk density (g/cm^3^). To correctly calculate soil
bulk density *accurate* cores of a known volume must be collected. These
cores are then returned to a laboratory to be dried and weighed.

*Materials needed:*

H-ring (core of known volume)

Putty knife (3 inch blade)

Sample tin (pre-tared, 6 oz)

Hammer (rubber tipped or rock hammer)

Trowel

Bulk density field sheet

*Optional supplies:*

Sturdy medium-sized knife (used for cleaning pit faces and sample
surfaces)

Piece of hard wood

*Obtaining the upper mineral sample:*

1.  Remove organic layer (leaves, twigs, moss, etc.) by carefully
    scraping this material aside, so that the top of the mineral soil is
    exposed and level (flat).

2.  Place the H-ring, sharpened side down, on top of the mineral soil.

3.  Push the ring into the soil as much as you can with your hands. Do
    not twist the H-ring.

4.  Once you've pushed the H-ring in as much as possible with your
    hands, place a piece of hard wood (or the putty knife if wood is
    unavailable) over the H-ring and *gently* hammer the H-ring into the
    soil until the top of the H-ring is flush with the soil surface.

    a.  Continually adjust where you are hammering so that the H-ring
        descends evenly into the soil.

    b.  If you meet strong resistance due to rocks or large roots, start
        over in a new spot.

5.  With your trowel and/or soil knife, dig a small trench on one side
    of the H-ring. It should be slightly deeper than the H-ring. The
    excavated area needs to be large enough that you can place the putty
    knife horizontally next to the base of the H-ring.

6.  Push the putty knife under the H-ring until it lies under the entire
    ring.

7.  Gently remove the H-ring from the soil, holding the putty knife in
    place so that no soil is lost from the bottom of the sample.

8.  Clean the surfaces of the H-ring so that the soil sample is clean
    and flush with the surface of the H-ring.

    a.  If you are tipping the H-ring over to clean the bottom surface,
        put your hand or an additional putty knife over the top of the
        H-ring so that no soil falls out when you tip it over.

9.  Place the H-ring in the pre-tared tin, being careful not to loose
    any sample.

10. Push the soil out of the H-ring into the tin, being careful not to
    spill any soil outside of the tin.

11. Label the tin with the sample ID.

12. Fill out the sample sheet with the following information: Sample ID,
    Tare ID, Name of person who took the sample, and Date obtained.

*Obtaining the lower (C horizon) mineral sample:*

Follow the instructions above, with four modifications: 1) there is no
need to remove the organic layer, 2) the H-ring will be pushed into the
side of the pit (versus on the soil surface), and 3) the pit side should
be cleaned off to make a level sampling surface, and 4) the bottom of
the pit should never be sampled (because this soil is often contaminated
with soil that has fallen from the sides of the pit).

*Tips:*

-   Before removing the soil from the H-ring (inside the tin), it can
    help to first push the knife into the center of the sample a few
    times, loosening the soil with the ring. This makes it easier to
    push the soil out.

-   If possible, work at removing the soil from the ring over a clean
    piece of paper or other clean surface. This way if a small amount of
    soil falls outside the tin, you can return it to the tin (rather
    than having to start over).

-   If the soil is really rocky, it is likely that you will be unable to
    get a good sample.

+------------+------+---------+------+----------+---------------------+
| **Sample   | **   | **      | **Da | **Sample | **Notes**           |
| ID**       | Tare | Sampled | te** | q        |                     |
|            | ID** | By**    |      | uality** |                     |
|            |      |         | **S  |          |                     |
|            |      | **(     | ampl | *        |                     |
|            |      | name)** | ed** | *(circle |                     |
|            |      |         |      | one)**   |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+
|            |      |         |      | good     |                     |
|            |      |         |      | fair     |                     |
|            |      |         |      | poor     |                     |
+------------+------+---------+------+----------+---------------------+