1.0 DOCUMENT INFORMATION
1.1 Document Title: TDE soil respiration data
1.2 Revision Date: April 8, 2003
1.3 Document Summary: Soil respiration observations collected from 1992 through 1999.
1.4 Sponsor: Office of Science, Biological and Environmental Research, U. S. DOE
2.1 Investigator and data set contact:
Paul J. Hanson (firstname.lastname@example.org)2.2 Title of Investigation:
Senior Research Staff Member
Environmental Sciences Division
Oak Ridge National Laboratory
Bethel Valley Road
P.O. Box 2008
Oak Ridge, TN 37831-6422
3.0 DATA SUMMARY
Point-in-time soil respiration data for the ambient, wet, and dry TDE treatment sites.
Soil respiration or net forest floor CO2 efflux (Rsoil) was measured with the LiCor 6200 closed-gas-exchange system and a custom-designed aluminum chamber having a surface area of 594 cm2 and a volume of 5227 cm3 (Hanson et al. 1993). The open bottom of the chamber was pressed into the litter layer to form the closed cuvette for measurements that lasted from 1.5 to 3 minutes depending on the season (i.e., shorter observations in the summer when rates were high). Permanent soil collars were not used to avoid inappropriate trapping of precipitation on the litter layers. At periodic weekly or biweekly intervals 30 observations per treatment (wet, ambient, and dry) were conducted at fixed locations along three transects of the TDE site representing upper, middle, and lower slope positions. Soil temperature and soil water content were monitored simultaneously with each observation. Soil moisture (%, cm3 cm-3) was measured with a time-domain reflectometer (Soil Moisture Equipment Corporation, Santa Barbara, Calif,) to a depth of 35 cm. Soil temperature (°C) was measured to ~10 cm with an OMEGA digital temperature probe. Soil-water-content data were converted to soil-water potential with the soil moisture release curves documented by Hanson et al. (1998; Hanson et al. 2003a).
5.0 OBSERVATION NOTES
Rsoil was measured from 1992 to 1999 to establish the seasonal patterns and evaluate potential TDE treatment effects. Data collected from 1994 to 1996 emphasized observations of seasonal patterns and TDE treatments, and Rsoil observations made from 1997 to 1999 were done to obtain supplemental information for cold soils and dry conditions to fill out the response surface relating Rsoil to temperature and soil-water potential. Wetting and drying periods associated with rain events were also targeted in 1998 and 1999 to test the influence of wet surface organic horizons on Rsoil.
6.0 DATA ORGANIZATION
Data are provided in comma delimited csv files where the first line includes the variable names and subsequent lines include the following data by year.
6.1 Variable, Definition, and Units
Column 2 = YEAR
1992 to 1999
Column 3 = DOY
Day of the year (1 to 365 or 366)
Column 4 = RDOY
Consequtive days begining January 1, 1992.
Column 5 = Y
Vertical position on the TDE site (1-lower slope to 10-upper slope).
Column 6 = X
Horizontal positon on the TDE site (1-west to 31-east).
Column 7 = TRT
Treatment of the TDE experiment: W = wet, A = ambient, D = dry
Column 8 = GROWTH
Presence of active (1) or nonactive (0) root growth.
Column 9 = TEMP
Soil temperature (°C) at 10 cm.
Column 10 = W15
Soil water content (%, v/v) from 0 to 15 cm.
Column 11 = W35
Soil water content (%, v/v) from 0 to 35 cm.
Column 12 = MP35
Soil matric potential (MPa) for the 0 to 35 cm depth.
Column 13 = SRESP
Soil respiration rate per unit of ground surface in µmol m-2 s-1.
6.3 Missing data: Yes.
6.4 Related Data Sets: None.
7.0 KNOWN ERRORS AND QUALITY ASSESSMEN
8.1 Limitations of the data:
8.2 Known Problems With The Data
Missing data for some variable are present as unfilled data cells.
8.3 Usage Guidance: Model parameters for soil respiration based on this data set can be found in Hanson et al. 2003b.
Hanson PJ, Wullschleger SD, Bohlman SA, Todd DE (1993) Seasonal and topographic patterns of forest floor CO2 efflux from an upland oak forest. Tree Physiol 13:1-15.
Hanson PJ, Todd DE, Huston MA, Joslin JD, Croker J, Augé. RM (1998) Description and field performance of the Walker Branch Throughfall Displacement Experiment: 1993-1996, ORNL/TM-13586, Oak Ridge National Laboratory, Oak Ridge, Tennessee.
Hanson PJ, Todd DE, Huston MA (2003) Walker Branch Throughfall Displacement Experiment (TDE) Chapter 2 In: Hanson PJ, Wullschleger SD, Eds, North American Temperate Deciduous Forest Responses to Changing Precipitation Regimes. Springer, New York, pp. 8-31.
Hanson PJ, OíNeill EG, Chambers MLS, Riggs JS, Joslin JD, Wolfe MH (2003b)
) Soil respiration and litter decomposition. Chapter 10 In: Hanson PJ,
Wullschleger SD, Eds, North American Temperate Deciduous Forest Responses
to Changing Precipitation Regimes. Springer, New York, pp. 163-189.
10.0 DATA LISTING
Click on the following to view all soil respiration data.
Once open the files can exported as text files with the 'Save As' command.