Soil Phosphorus Landscape scale Survey in the Luquillo Mountains of Puerto Rico 0-20cm

Data File Identifier: 
Soil Phosphorus Landscape scale Survey in the Luquillo Mountains of Puerto Rico 0-20cm
Quality Control Level: 
Derived and Interpreted products
Data Set: 
Number of header rows in file(s): 
15
Periodicity of Sample Number: 
1.00
Periodicity of Sample: 
month
From Date: 
Thu, 07/01/2010 - Fri, 07/30/2010
Research Location: 
Variables: 
Record ID
Variables: 
Site Name
Variables: 
Bedrock
Variables: 
Catena
Variables: 
Soil Depth
Variables: 
Elevation
Variables: 
Mean Elevation
Variables: 
Average flux density
Variables: 
NaHCO3-Pi
Variables: 
NaHCO3-Pt
Variables: 
NaHCO3-Po
Variables: 
NaOH-Pi
Variables: 
NaOH-Pt
Variables: 
NaOH-Po
Variables: 
HCl-P
Variables: 
Residual P
Variables: 
Total P
Variables: 
Tau P
Variables: 
Residual to Total
Variables: 
Iron Oxide
Data Set Methods
Lab Analysis: 

Soils were collected in Luquillo National Forest, Puerto Rico, in July 2010.
We collected soils from 16 subwatersheds in a full factorial combination of 2 forest types (colorado, tabonuco) and 2 parent materials (quartz diorite, volcaniclastic)
In each subwatershed we dug 9 soil pits to a depth of 80cm (0-20, 20-50, 50-80). Three pits were located in ridge, three in slope, and 3 in valley positions.
This yielded a total of 432 soil samples, which were air dried at the University of Pennsylvania. A subsample was then shipped to Brown University
At Brown, equal mass of the three replicates from a given topographic position within a subwatershed were combined to make a composite sample (e.g. all three 0-20cm depth ridge samples from site COOX-1 were combined).
We analyzed for P fractions using a modified Hedley fractionation, extracting sequentially with 0.5N NaHCO3 and 0.1N NaOH. Each extract was measured for inorganic P on a westco smartchem 200 analyzer.
Each extractant was also digested with persulfate and reanalzyed for total P, organic P was determined by difference between P in the persulfate digest and P in the undigested extractant.
Every 10th sample was run in triplicate to ensure reproducibility.
Each of the composite samples was also digested by lithium borate flux fusion and run by XRF to determine total elements, and by ICP-MS to determine trace elements. This work was done
by ALS Chemex (SParks, NV).
The data presented on the next page are concentrations of different P forms per gram oven dry weight of soil.

Tau P refers to the loss (<0) or gain (>0) of P relative to parent material, using the P concentrations of soil and parent material referenced to niobium (see Porder and Chadwick, 2009). Tau = -0.5 represents a 50% loss
of P relative to the parent rock.

Dissemination: 
unrestricted
Publish to National CZO: 
Publish