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A Global Database of Soil Respiration Data, Version 3.0
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This data set provides an update of the soil respiration database (SRDB), a near-universal compendium of published soil respiration (RS) data. Soil respiration, the flux of autotrophically- and heterotrophically-generated CO2 from the soil to the atmosphere, remains the least well-constrained component of the terrestrial Carbon cycle. The database encompasses all published studies that report at least one of the following data measured in the field (not laboratory): annual RS, mean seasonal RS, a seasonal or annual partitioning of RS into its sources fluxes, RS temperature response (Q10), or RS at 10 degrees C. The SRDB's orientation is thus to seasonal and annual fluxes, not shorter-term or chamber-specific measurements, and the database is dominated by temperate, well-drained forest measurement locations. The data set includes a file of RS data and a linked file of study bibliographic data; both files are in comma-separated format.

SRDB map 

Figure 1. Locations of 5173 SRDB database observations, colored by biome. Map produced by the companion srdb.R script.

Data and Documentation Access:

Get Data:

Companion Files:

   • srdb.R: An R-language script containing functions for error-checking and mapping of study locations.

   • A collection of Excel spreadsheets recording the calculation of annual flux for each included study.

Related Data Set:

Raich, J. W., and W. H. Schlesinger. 2001. Global Annual Soil Respiration Data (Raich and Schlesinger 1992). Data set. Available on-line [] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/622

Data Citation:

Cite this data set as follows:

Bond-Lamberty, B.P. and A.M. Thomson. 2014. A Global Database of Soil Respiration Data, Version 3.0. Data set. Available on-line [] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA.

Table of Contents:

1. Data Set Overview:

Project: Soil Collections

Investigators: B. Bond-Lamberty and A.M. Thomson. 

The compilers of the SRDB database (Bond-Lamberty and Thomson, 2010) make it available to the scientific community both as a traditional static archive (ORNL DAAC) and as a dynamic community database that will be updated over time by interested users. The dynamic version of the database is hosted on Google Code: We recommend that citations to this dynamic database always include a version number and download date.

The SRDB encompasses all published studies that report at least one of the following data measured in the field (not laboratory): annual RS, mean seasonal RS, a seasonal or annual partitioning of RS into its sources fluxes, RS temperature response (Q10), or RS at 10 degrees C. The SRDB was designed to capture and make available for analysis the large number of RS studies published since the 1960s. The data set includes a file of RS data and a linked file of study bibliographic data; both files are in comma-separated format. In Version 3.0, An R script with functions for error-checking and mapping of study locations is also included as a companion to the data set.

The ORNL DAAC released Version 1.0 in 2010, Version 2.0 in 2012, and Version 3.0 in 2014, and will update the database on an ongoing basis to incorporate changes and additions submitted by the RS community via the Google Code site and by Bond-Lamberty and Thomson. Transaction logs for the SRDB-data and SRDB-study files are maintained on the Google code site.

ORNL DAAC Version Record

SRDB Version ORNL DAAC Release Date Studies Included Records Date Range Date Superseded
Version 3.0 2014/07/24 1,487 5,173 1961-2011  
Version 2.0 2012/03/01 1,021 4,387 1961-2009 2014/07/24
Version 1.0 2010/04/30 818 3,379 1961-2007 2012/03/01

Version 3.0: Data from 1,487 studies have been entered into the database, constituting 5,173 records. The data span the measurement years 1961-2011 and are dominated by temperate, well-drained forests. The source for Version 3.0 is srdb_20131218a from the Google Code website.

Versions 1.0 and 2.0: The source for Version 2.0 is srdb_20110524a from the Google Code website. Note that past versions are considered outdated and Version 3.0 should be accessed for updated data. For access to past versions of the database, please contact the DAAC as indicated in Section 6 of this document.


2. Data Description:

Spatial Coverage

Point-based measurements with global extent (see Fig. 1). Coordinates are provided for each sample location.

Site boundaries: (All latitude and longitude given in decimal degrees)

Site (Region) Westernmost Longitude Easternmost Longitude Northernmost Latitude Southernmost Latitude Geodetic Datum
Global (point) -162.2 175.5 78.1667 -78.02 Unknown

Temporal Coverage

Compilation of published measurements taken between 1961/01/01 and 2011/12/31. The study date of each record is provided in the data set.

Temporal Resolution


Data File Information

The main data file "srdb-data-V3.csv" is a comma-separated file of all the soil respiration and contextual data. Bibliographic information for the studies that appear in the main data file can be found in the "srdb-studies-V3.csv" file. The “Study_number” field is common to both files and indexes the srdb-studies to srdb-data.

Missing values:  In both files, if a value (numeric or text) is missing for a study, that field is left blank.

File Description: srdb-data-V3.csv

Column Number Column Name Column Description and Units
1Record_number Record number
2Entry_date Entry date
3Study_number Study number; index into the studies database
4Author Name of first author
5Duplicate_record Is record a known duplicate? (Study number)
6Quality_flag Quality control.

Quality control flags include:

Q0    default/none
Q01  estimated from figure
Q02  data from another study
Q03  data estimated--other
Q04  potentially useful future data
Q10  potential problem with data
Q11  suspected problem with data
Q12  known problem with data
Q13  duplicate?
Q14  inconsistency
Further details can generally be found in the notes field (#107 below)
7Contributor Data contributor
Site and measurement data
8Country Country
9Region State/province/region
10Site_name Name of study site
11Study_midyear Year study was performed (middle year if multiple years)
12YearsOfData Years of data; always ≥1
13Latitude Latitude, decimal; positive=north, negative=south
14Longitude Longitude, decimal; positive=east, negative=west
15Elevation Elevation, m
16Manipulation Manipulation performed (CO2, fertilization, etc.)
17Manipulation_level Degree of manipulation performed
18Age_ecosystem Time since ecosystem established, years. This is used when, e.g., the time of conversion of forest to agriculture is known
19Age_disturbance Time since disturbance, years
20Species Dominant species
21Biome Biome (boreal, temperate, etc). Subjective
22Ecosystem_type Ecosystem type (grassland, forest, etc). Subjective
23Ecosystem_state Ecosystem state (managed, unmanaged, natural). Subjective. Unmanaged means human management or disturbance in the past, but not currently.
24Leaf_habit Dominant leaf habit (deciduous, evergreen)
25Stage Developmental stage (aggrading, mature). Subjective
26Soil_type Soil description (classification and texture)
27Soil_drainage Soil drainage (dry, wet). Subjective. Dry means well-drained uplands; wet peatlands, swamps, etc.
28Soil_BD Soil bulk density, g cm-3
29Soil_CN Soil C:N ratio
30Soil_sandsiltclay Soil sand:silt:clay ratio
31MAT Reported mean annual temperature, C
32 MAP Reported mean annual precipitation, mm
33 PET Reported potential evapotranspiration, mm
34 Study_temp Annual temperature in year of study, C
35Study_precip Annual precipitation in year study of study, mm
36Chamber_method Chamber method
37Meas_method CO2 measurement method
38 Meas_interval Mean interval between Rs measurements, days
39 Annual_coverage Annual_coverage of Rs measurements, fraction (1.0= full year)
40 Partition_method Method used to partition RS source fluxes, following Bond-Lamberty et al. (2004)
Annual and seasonal RS fluxes
41 Rs_annual Annual C flux from soil respiration, g C m-2. This can either be reported directly by the study, calculated from reported mean fluxes, or estimated from a figure (in which case a quality control note is made, field 6)
42Rs_annual_err Error (typically plot-to-plot) for Rs_annual, g C m-2
43Rs_interann_err Interannual error reported for Rs_annual, g C m-2. This is occasionally reported by authors, or defined as the standard deviation between year ‘i’ and year ‘i+1’ (N=2)
44Rs_max Maximum RS flux, µmol m-2 s-1
45Rs_maxday Maximum RS flux day of year
46Rs_min Minimum RS flux, µmol m-2 s-1
47Rs_minday Minimum RS flux day of year
48Rlitter_annual Annual RS flux from litter, g C m-2 fraction
49Ra_annual Annual autotrophic RS flux, g C m-2
50Rh_annual Annual heterotrophic RS flux, g C m-2
51Rc_annual Root contribution to Rs_annual, annual fraction
52Rs_spring Mean spring RS flux, µmol m-2 s-1. Seasons are defined by authors
53Rs_summer Mean summer RS flux, µmol m-2 s-1
54Rs_autumn Mean autumn RS flux, µmol m-2 s-1
55Rs_winter Mean winter RS flux, µmol m-2 s-1
56Rs_growing Mean growing RS flux, µmol m-2 s-1
57Rs_wet Mean wet season RS flux, µmol m-2 s-1
58Rs_dry Mean dry season RS flux, µmol m-2 s-1
59RC_seasonal Root contribution to seasonal RS, fraction
60RC_season Season of RC_seasonal
Response of RS to temperature and moisture
61Model_type Type of temperature-response model used
62Model_effect Temperature effect on RS (none, positive, negative)
63Model_output_units Temperature-response model output units
64Model_temp_range Soil temperature range over which model fitted
65Model_N Model N
66Model_R2 Model r-squared
67T_depth Depth at which soil temperature recorded, cm. A value of -200 (i.e., 2 m above ground) is used for air temperature
68Model_paramA Model parameter A
69Model_paramB Model parameter B
70Model_paramC Model parameter C
71Model_paramD Model parameter D
72Model_paramE Model parameter E
73WC_effect Soil water effect on RS
74R10 RS at 10 C, µmol m-2 s-1
75Q10_0_10 Q10 temperature response, 0-10 C .Q10 values are either reported by authors, calculated from reported RS-temperature regressions, or occasionally estimated from figures (in which case a quality control note is made, field 6)
76Q10_5_15 Q10 temperature response, 5-15 C
77Q10_10_20 Q10 temperature response, 10-20 C
78Q10_0_20 Q10 temperature response, 0-20 C
79Q10_other1 Q10 temperature response, other temp range
80Q10_other1_range Temperature range of Q10_other1, C
81Q10_other2 Q10 temperature response, other temp range
82Q10_other2_range Temperature range of Q10_other2, C
Ancillary pools and fluxes
83GPP Annual gross primary production at site, g C m-2
84ER Annual ecosystem respiration at site, g C m-2
85NEP Annual net ecosystem production at site, g C m-2
86NPP Annual net primary production at site, g C m-2
87ANPP Annual aboveground NPP at site, g C m-2
88BNPP Annual belowground NPP at site, g C m-2
89NPP_FR Annual fine root NPP at site, g C m-2
90TotDet_flux Annual total litter flux, g C m-2. This should be the sum of Litter_fluxand Rootlitter_flux
91TBCA Total belowground carbon allocation at site, g C m-2
92Rootlitter_flux Annual aboveground litter flux, g C m-2. This is reported very inconsistently (leaf only, leaf and fine woody material, all material, etc). Generally this should not include large woody material
93TotDet_flux Annual total litter flux, g C m-2. This should be the sum of Litter_flux and Rootlitter_flux
94Ndep Annual nitrogen deposition, g N m-2
95LAI Leaf area index at site, m2 m-2. Hemispheric (one-sided) if possible
96BA Basal area at site, m2 ha-1
97C_veg_total Total carbon in vegetation, g C m-2. This should be the sum of C_AG and C_BG. For this and all "C_" fields, biomass is converted to carbon using a ratio of 0.5 unless study-specific values are available
98C_AG Total carbon in aboveground vegetation, g C m-2
99C_BG Total carbon in belowground vegetation, g C m-2
100C_CR Total carbon in coarse roots, g C m-2
101C_FR Total carbon in fine roots, g C m-2
102C_litter Total carbon in standing litter, g C m-2
103C_soil Total carbon in soil organic matter, g C m-2
104C_soildepth Depth to which soil C recorded, cm
105Notes Notes

File Description: srdb-studies-V3.csv

Column Number Column Name Column Description
1 Study_number Study number; used as a lookup from srdb-data
2 Authors Study authors
3 Title Study title
4 Source Study source (usually journal name)
5 Volume Volume number
6 Issue Issue number
7 BP Beginning page
8 EP Ending page
9 Pub_year Publication year
10 Notes Notes
11 Abstract Abstract
12 Citations Citations
13 DE Data entry: entered into srdb-data (Y, N)?
14 DLD Downloaded: study acquired (Y/N)?
15 DOI Digital object identifier
16 nonEnglish Is study in a non-English language (Y/N)?
17 Rank Rank (1=highly relevant, 4=not relevant). Note this score is not an assessment of the study's scientific merit or validity; it's simply a judgment, based on reading the abstract and title, of how relevant this study is to the database (i.e., is it likely to have appropriate data?)
18 SearchDate Date search performed
19 SearchTerm Web of Science search term used

Companion File Information:

3. Data Application and Derivation:

This is a database compiled from published studies about soil surface CO2 flux (soil respiration; RS) measured in the field and intended to serve as a resource for scientific analysis. 

The primary RS units used were gC/m2/yr (for annual fluxes) and umol/m2/s (for mean seasonal fluxes); values were converted as necessary from those provided by study authors. A variety of ancillary data were also entered when reported, including site-related and experimental data, information on ecosystem structure and function, methods used, etc.; we assumed a 12:44 ratio of C to CO2 molecular weights, and that biomass was 50% C (unless specified otherwise in the study).

4. Quality Assessment:

Data were crosschecked against a number of other RS data collections and meta-analyses (Hibbard et al., 2005; Chen and Tian, 2005; Burton et al., 2008; Sottaet al., 2004). Quality flags were assigned based on information provided in a given study and best judgment.

5. Data Acquisition Materials and Methods:

For the compilation of Version 1, investigators collected all available studies in the peer-reviewed scientific literature reporting RS measured in the field; lab incubation studies were not included. The ISI Web of Science constituted the primary source of published studies; search terms used included soil respiration, soil CO2 evolution, etc., and were conducted through the 2008 publication  year. We used each study's title and abstract to decide whether to acquire it; ~40% of the almost 4700 studies were acquired and examined. 

In version 2.0, publications from 2009, 2010 and from the first half of 2011 were included and RS data from 164 studies have been added. The Google Earth.kmz file of site locations was updated. Additionally, a number of corrections have been made. A number of Age_disturbance fields have been corrected and completed. The Partition_method field has been fixed for many records. Finally, three fields have been deleted: Chamber_method, CH4_flux, N2O_flux. These fields were inconsistent or almost never used.

In Version 3.0, publications from 2012 and RS data from a total of 466 new studies were added. Many corrections were made to older data and a new R script for error-checking and mapping was created. The Google Earth.kmz file was removed and the field CO2_method was renamed to Meas_method. Additionally, two new fields titled Meas_interval and Annual_coverage were added to the data.

Short term experiments (i.e., RS measurements made over less than 1-2 weeks) were not entered unless the study authors extrapolated their results to seasonal or annual values; the database is in general not designed to accommodate instantaneous or short-term measurements. In general we did not do additional research to find older publications that might not be listed in the Web of Science.  To qualify for inclusion, a study had to report at least one of the following data:

If at least one of these data was reported, or could be calculated with few or no assumptions, e.g., easily estimated from points in a figure, the study was entered into the database. For example, sometimes a study will show monthly soil respiration in a figure but not compute an annual flux, and so estimates were made from the figure. This was noted in a quality flag.

When it was necessary to calculate or estimate annual flux for one of the studies, these calculations and notes were recorded in an Excel spreadsheet (*.xlsx). File names start with the assigned four-digit “Study_number” that indexes the srdb-studies and srdb-data files. For example, "0020 WitkampEcology 1966.xlsx" and "4634 Webster JGR 2008.xlsx". These spreadsheets are provided as a companion file and have been compiled and compressed into a single file,

6. Data Access:

This data is available through the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Data Archive Center:

Contact for Data Center Access Information:
Telephone: +1 (865) 241-3952

7. References:

Bond-Lamberty, B. and A.M. Thomson. 2010. A global database of soil respiration measurements, Biogeosciences, 7, 1321-1344, doi:10.5194/bgd-7-1321-2010.

Burton, A. J., Melillo, J. M., and Frey, S. D. 2008.: Adjustment of forest ecosystem root respiration as temperature warms, Journal of Integrative Plant Biology, 50, 1467-1483, doi:10.1111/j.1744-7909.2008.00750.x.

Chen, H., and Tian, H.-Q. 2005. Does a general temperature-dependent Q(10) model of soil respiration exist at biome and global scale?, Journal of Integrative Plant Biology, 47, 1288-1302.

Hibbard, K. A., Law, B. E., and Sulzman, J. 2005. An analysis of soil respiration across northern hemisphere temperate ecosystems, Biogeochemistry, 73, 29-70, doi:10.1007/s10533-004-2946-0.

Sotta, E. D., Meir, P., Malhi, Y., Nobre, A. D., Hodnett, M., and Grace, J. 2004. Soil CO2 efflux in a tropical forest in the central Amazon, Global Change Biol., 10, 601-617, doi:10.1111/j.1529-8817.2003.00761.x.