KBS044: Deep Core Bulk Density and Archiving

Active

In use from 2001-01-01

Protocol

Note: Due to the need to perform moisture and C/N analyses, samples must be weighed wet, sieved, mass of rocks measured and recorded before drying at 60 ° C for 48 hrs.

Materials:

  • Intact core sample
  • # 10 and # 20 paper bags (pre-labeled)
  • Meter Stick
  • 4mm sieve (Treatment specific)
  • Data Sheets
  • Drying Oven @ 60 ° C
  • Balance
  • Custom™ Soil Grinder
  • Pint and Quart Canning Jars (pre-labeled)
  • General Procedure

    1. Pre-label paper bags with the appropriate information about the sample (e.g. date, plot, station, core#, horizon, variate)
    2. Delineate horizons (Ap, Bt, Bt2).
    3. Measure core height for each horizon.
    4. Carefully cut open core liner and remove the first horizon.
    5. Weigh first (A) core horizon section, record.
    6. Sieve A horizon, weigh rocks >4mm, record mass.
    7. Place sieved core section in labeled paper bag, discard rocks >4mm.
    8. Brush sieve and repeat procedure for all horizon sections.
    9. Place samples and 10 empty paper bags (for each size used) in drying oven at 60 ° C for at least 48 hours.
    10. Remove samples and paper bags from oven and allow to cool for at least 15 minutes.
    11. Weigh samples and paper bags. Determine soil mass by subtracting mean bag weight from the weight of the soil core + bag weight.
    12. Add weight of rocks to soil dry weight for total dry weight.

    Calculations:

    Bulk density (g/cm3) = W/V
    where
                  W = total oven-dry weight in grams   Dry weight of sieved soil + weight of rocks >4mm
    
                  V = volume of core section in cm3      Cylindrical Volume = (π)(r2)h
    
    % Soil Moisture = ((TW – W)/W) * 100
    where
                  TW = Total wet soil weight in grams
                   W  =  Total dry soil weight in grams + weight of rocks >4mm – bag weight
    

    Archival Procedure:

    1. Run entire dried individual horizon section through the Custom™ Soil Grinder.*
    2. Clean out grinder between each sample.
    3. Store ground sample in pre-labeled canning jar (pint for A and quart for B horizon).
    4. Archive jars in original jar boxes in order of T-R-S-C-H where:
      T = Treatment# R = Replicate# S = Station# C = Core# and H = Horizon

    *Deep core soil archived for 2010 was not ground.

Author:

Datatables