DATA SET IDENTIFIER: Spatial Variation of Soil Carbon, Nitrogen and Phosphorus in the Luquillo Experimental Forest (LEF) (LEF_SOIL_CNP)

PROJECT TITLE: Soil Carbon and Nutrients in the Luquillo Experimental Forest (LEF) (Modeling and Validating the Spatial Variation of Soil Carbon, Nitrogen and Phosphorus in the Luquillo Experimental Forest (LEF))

PROJECT DESCRIPTION: In this study, we examine the spatial variability of soil carbon, nitrogen and phosphorus in the Luquillo Experimental Forest (LEF) using a spatially explicit version of the CENTURY biogeochemistry model. We took soil samples from 119 locations in the Luquillo Mountain during the summer of 1998 and 1999. Then we compared the simulated soil C, N and P pools with observed values as a way to validate our simulation results.

LTER CORE AREAS: (Annotate all that apply)

LEF LTER 1 RESEARCH TOPIC: (Annotate all that apply)

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DATA SET FILES (SUBSETS):

RESEARCH LOCATION: We carried out this study in the Luquillo Experimental Forest (LEF) in northeastern Puerto Rico (18 ^o 18’ N; 65 ^o 50’ W, State Plane: easting 209000-229130 m, northing 45760-57280 m).

INVESTIGATORS:

PRINCIPAL INVESTIGATORS E-MAIL address

OTHER RESEARCHERS E-MAIL address

CONTACT PERSONS E-MAIL address Phone Number (Include area code)

SOURCE OF FUNDING (SPONSOR): National Science Foundation to LTER_LUQ project

DATA SET ABSTRACT: Hongqing Wang, a Ph.D graduate student of SUNY-ESF, with the help of many others, took soil samples in 119 locations over the entire Luquillo Experimental Forest (LEF) during the summer of 1998 and 1999. Soil organic carbon, total nitrogen and acid-extractable phosphorus were measured in the laboratory of SUNY-ESF; soil moisture and bulk density were measured at the laboratory of the El Verde Station of UPR. The geodetic coordinates (Lat., Lon.) and elevation of each sampling location were determined using a Global Positioning System (GPS Pathfinder Basic Receivers, Trimble Navigation Ltd.) in the field. Meanwhile, slope angle, aspect and topographic features (Ridge, slope I (<35 deg.), slope II (>=35 deg.), valleys) were also measured and observed in the field.

DATA SET METHODS: Sampling: We collected soil samples (n= 119) along most forest trails over the entire mountain with the rough transects at 200 - 1000 m intervals. While we collected the majority of samples near the trails, we also took some samples far away from the trails for the purpose of considering the geomorphic and topographic features. The sampling intervals were smaller in transects where we could see that the vegetation and soil types and topography varied rapidly, and larger in areas of relatively uniform vegetation, soil and topographic features. At each site, within a radius of approximate 30-m, we removed the leaf litter from the forest floor and took 5 subsamples of 0 to 30-cm depth of mineral soil with a 1.85-cm diameter soil corer. Then the subsamples were mixed together in plastic bags as the representative soil sample for that site. We sealed the bags to retain moisture.

For georeference and topographic data (location, elevatioin, slope angle, aspect and topographic type):
We used a Global Positioning System (GPS Pathfinder Basic Receivers, Trimble Navigation Ltd.) to determine the geodetic coordinates (Lat., Lon.) of each site (using USGS topographic map to determine the location and elevation for sample #101-119). We used a clinometer (SUUNTO, SF-02920, Finland) and a compass to measure the slope and aspect of each site. When forest cover was dense and impeded the GPS readings, we placed the GPS Receiver in an open lot as near as possible to the sampling site. We measured simultaneously the direction and distance between sampling site and the GPS site in order to get the geodetic coordinate of the sampling site. We classified the topography as ridge tops, slopes and valleys according to Scatena et al. (1995) except that we did not divide valleys into upland and riparian valleys. Instead we divided slope as steep slope (≥35 ° ) and less steep slope (<35 ° ). We obtained the GPS files in the field each day and then downloaded them from the GPS receiver to a laptop computer. The University of Puerto Rico provided the base station files for the same sampling time period. Using these base station files and performing the differential correction operation in the PFINDER software, we corrected our field GPS files to get the corrected geodetic coordinates (LAT., LON.) and then converted to Geocentric coordinates (state plane, meters) for each sampling site. We derived the elevation and geodetic coordinate for each site from our GPS data processing. We obtained the slope angle and aspect of each sampling site from field measurement.

For soil properties:
We dried a portion of each soil sample (105 ° C) in the laboratory of El Verde Field Station to analyze for gravimetric moisture content (g H2O/ 100 g dry soil) and bulk density (g dry soil/ cm³) determinations. The rest of each sample was air-dried, ground and sieved (< 2 mm) for the Soil Organic Carbon (SOC) analysis. For each soil sample, we used the Walkley-Black method to measure the SOC content, the Kjeldahl method for total nitrogen and extraction method (phosphorus soluble in dilute acid-fluoride) for available phosphorus (Bickelhaupt and White 1982; Black 1965).

REFERENCES:
Bickelhaupt, D.H. and White, E.H. 1982. Laboratory Manual for Soil and Plant Tissue Analysis. School of Forestry, State University of New York, College of Environmental Science and Forestry, Syracuse, New York 13210.

Black, C.A. (Eds.). 1965. Methods of soil analysis. Part 2: Chemical and microbiological properties. American Society of Agronomy, Inc., Publisher, Madison, Wisconsin, USA.

User’s Manual for GPS Pathfinder Basic Receivers, Trimble Navigation Ltd.,1989. Scatena, F. N., and Lugo, A. E. 1995. Geomorphology, disturbance, and the soil and vegetation of two subtropical wet steepland watersheds of Puerto Rico. Geomorphology 13: 199-213.

CROSS-REFERENCES (other data sets related to this one):

SAMPLE LOCATION: The entire Luquillo Experimental Forest (LEF).

STORAGE SITES (of data files): Stored at the Systems Ecology Laboratory, 301 Illick Hall, SUNY ESF, Syracuse NY 13210; ITES' Data Management files DM-002, Drawer #4 ("Results of analysis of soil samples taken in the Luqillo Experimental Forest (LEF) by:Hongqing Wang in 1998.6.29-7.15 1999.6.10-6.15.")

INVESTIGATOR'S ASSIGNED KEYWORDS: spatial variability; soil organic carbon, total nitrogen, phosphorus, soil moisture content, bulk density, georeference, topography

LEF LTER OFFICIAL KEYWORDS (See table): LEF, CARBON, NITROGEN, PHOSPHORUS, SOILS, THESIS

PUBLICATIONS:

Wang H.Q. 2001. Dynamic modeling of spatial and temporal variations of forest carbon and nitrogen inventories, including their responses to hurricane disturbances in the Luquillo Mountains, Puerto Rico. Ph.D. Dissertation, State University of New York, College of Environmental Science and Forestry, Syracuse N.Y.

Wang, H.Q., C.A.S. Hall, and J.D.Cornell. Modeling the effects of hurricane Hugo on spatial and temporal variation in primary productivity and soil carbon and nitrogen in the Luquillo Experimental Forest, Puerto Rico. Global Change Biology.(in press)

Wang, H.Q., J.D.Cornell, C.A.S. Hall, and D. Marley. Spatial and seasonal dynamics of surface soil carbon in the Luquillo Experimental Forest, Puerto Rico. Ecological Modeling. 147(2):105-122

Wang, H.Q., C.A.S. Hall, J.D. Cornell, and M.H.P. Hall. Spatial dependence and relationship of soil organic carbon and soil moisture in the Luquillo Experimental Forest, Puerto Rico. Landscape Ecology, 17(8):671-684

Wang, H.Q., C.A.S. Hall, F.Scatena, N. Fetcher and Wu Wei. 2002. Modeling the spatial and temporal variability in climate and primary productivity across the Luquillo Mountains, Puerto Rico. Forest Ecology and Management. 179(1-3):69-94

DISSEMINATION: UNRESTRICTED

REASONS TO RESTRICT DATA IN THIS DATA SET BEYOND ITS TWO YEAR POLICY PERIOD*:

*WILL HAVE TO BE APPROVED BY LTER PRINCIPAL INVESTIGATORS: J. ZIMMERMAN, A. LUGO , D.J. LODGE

SITES DESCRIPTIONS: (This segment added from Waide and Schaefer, 1997)
The Luquillo Experimental Forest (LEF) LTER site is located in the Luquillo Mountains in eastern Puerto Rico. The LEF is congruent with the Caribbean National Forest, part of the USDA Forest Service National Forest System. The LEF occupies 11,231 ha of land with elevations ranging from 100 to 1079 m above sea level. In this steep, deeply-dissected terrain, landslides are the most common soil and vegetation disturbance. They are triggered by periods of intense rainfall, and are most frequent near road cuts. Soils in the Luquillo Mountains are deep clays, well-weathered but nutrient rich. Soils at higher elevations are continuously wet and unstable, with low permeability and high susceptibility to failure. As much as 20% of the forest is stony and lacks soil cover. Soils are derived from volcanoclastic andesitic sandstones and siltstones that were deposited undersea and uplifted repeatedly from the mid-Cretaceous through the Pliocene (Soil Survey Staff 1995). A detailed soil map has been prepared for the LTER 16 ha Hurricane Recovery Plot (Soil Survey Staff 1995). (For more details –text file)

Geographical positional system (GPS) Coordinates for each location:

VARIABLES (ATTRIBUTES):

VARIABLES: .

DATE OF LAST REVIEW: October 5, 2004
DATE OF LAST ENTRY: 6/15/1999
STAGE OF DATA SET MANAGEMENT (dates):
RECEIVED ENTERED: Sep 2000
FILED ON-LINE: FEB 7, 2001
REVIEWED BY RESEARCHER
FILING MEDIA:
NAME OF DOCUMENTATION FILE: LTERDB110.HTM
NAME OF ON - LINE CATALOG: LTERDBAS
RECORD #: 110
DOCUMENT TYPE: MAGNETIC MEDIA ONLY
PRIORITY TO BE ENTERED: N/A

Rev. date of this form: 8 June 2000 (updated Feb 7, 2001)