Dataset: Soil exchangeable cations 2008-2009

Abbreviation for site

Pit number (1-3). The pits were located at 0, 120, and 240 degrees from the plot center. The coring was performed every 60 degrees; therefore pit 2 was associated with core 3, and pit 3 associated with core 5.

Simple soil horizon id. B horizons were often not further identified in the field, e.g. as Bh, Bhs, Bs, or Bw.

For sorting purposes, each horizon type was given a number: Oa=1, A=2, E=3, B=4, C=6 (not sure what happended to 5)

Upper boundary depth of the horizon. Zero was assigned to the top of the Oa, if present, or A.

Lower boundary depth of the horizon. Zero was assigned to the top of the Oa, if present, or A

A plus sign next to the lowest boundary in a soil profile indicates that the soil was deeper than this boundary depth

Exchangeable aluminum (Al3+) determined with a 1 molar ammonium chloride extraction

Exchangeable calcium (Ca2+) determined with a 1 molar ammonium chloride extraction

Exchangeable magnesium (Mg2+) determined with a 1 molar ammonium chloride extraction

Exchangeable potassium (K+) determined with a 1 molar ammonium chloride extraction

Exchangeable sodium (Na+) determined with a 1 molar ammonium chloride extraction

Extractable iron (Fe) determined with a 1 molar ammonium chloride extraction

Extractable manganese (Mn) determined with a 1 molar ammonium chloride extraction

Organic carbon determined by elemental analyzer

Total nitrogen determined by elemental analyzer. The instrument calibration was off for the lower concentrations and values of 0.10% or lower were set as missing data (.)

Bulk density calculated using an individual equation developed by Juliette Juillerat for each site from the bulk densities core of increment samples. Carbon not used in the equation.

Bulk density calculated using an equation developed by Juliette Juillerat for all sites combined from the bulk densities core of increment samples. Carbon not used in the equation. BD =0.07229+0.41609*ln(midpoint of horizon depth in cm))

From an equation developed in Watershed 3 of Hubbard Brook Experimental Forest that uses carbon. Not published. BD =1.4-0.756*log(org-C in %)

If the upper boundary was less than 10 cm, the equation with organic carbon was used. If not, the overall equation was used (developed from all 18 sites and based on the midpoint depth of the horizon). The shallow, high-carbon horizons were better suited to the equation using carbon.

The mass of the soil horizon per square meter, calculated from bulk density and horizon thickness. Used to calculate pools

The lower boudary minus the upper boundary, expressed in meters. Used to calculate pools.

The weight of the horizon sampled in a 15x15 cm frame. This was used in place of the calculated mass where feasible because it was deemed more accurate. Usually the average from three frames sampled adjacent to the soil pit.

Exchangeable aluminum (Al3+) pool calculated from concentration (determined with a 1 molar ammonium chloride extraction) and mass per square meter.

Exchangeable calcium (Ca2+) pool calculated from concentration (determined with a 1 molar ammonium chloride extraction) and mass per square meter.

Exchangeable magnesium (Mg2+) pool calculated from concentration (determined with a 1 molar ammonium chloride extraction) and mass per square meter.

Exchangeable potassium (K+) pool calculated from concentration (determined with a 1 molar ammonium chloride extraction) and mass per square meter.

Exchangeable sodium (Na+) pool calculated from concentration (determined with a 1 molar ammonium chloride extraction) and mass per square meter.

Extractable iron (Fe) pool calculated from concentration (determined with a 1 molar ammonium chloride extraction) and mass per square meter.

Extractable manganese (Mn) pool calculated from concentration (determined with a 1 molar ammonium chloride extraction) and mass per square meter.