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Investigation:

ND-02 (Davidson / Stone / Markewitz / Carvalho / Sa / Vieira / Moutinho / Figueiredo)

LBA Dataset ID:

ND02_SOIL_CO2_FLUX

Originator(s):

1. SALIMON, C.I.
2. DAVIDSON, E.A.
      3. VICTORIA, R.L.
4. MELO, A.W.F.

Point(s) of Contact:

ORNL DAAC User Services Office Oak Ridge National Laboratory Oak Ridge, Tennessee 37 (ornldaac@ornl.gov)

Dataset Abstract:

The objectives of this project were to determine the effects of land-use change and native soil fertility on soil respiration in pastures, secondary forests, and primary forests near Rio Branco, Acre. We were also investigating the relationship between CO2 flux and soil carbon stocks and whether CO2 flux can be used as an indicator of the degree of ecosystem degradation. CO2 flux measurements were made in the field with an infrared gas analyzer on a monthly basis in 16 sites.

Beginning Date:

1999-06-01

Ending Date:

2002-06-30

Metadata Last Updated on:

2012-02-29

Data Status:

Archived

Access Constraints:

PUBLIC

Data Center URL:

http://daac.ornl.gov/

Distribution Contact(s):

ORNL DAAC User Services Office Oak Ridge National Laboratory Oak Ridge, Tennessee 37 (ornldaac@ornl.gov)

Access Instructions:

PUBLIC

Data Access:

IMPORTANT: The LBA-ECO Project website is no longer being supported. Links to external websites may be inactive. Final data products from the LBA project can be found at the ORNL DAAC. Please follow the fair use guidelines found in the dataset documentation when using or citing LBA data.
Datafile(s):

LBA-ECO ND-02 CO2 Flux from Soils in Forests and Pastures, Acre, Brazil: 1999-2001:  http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1066

Documentation/Other Supporting Documents:

LBA-ECO ND-02 CO2 Flux from Soils in Forests and Pastures, Acre, Brazil: 1999-2001:  http://daac.ornl.gov/LBA/guides/ND02_Soil_CO2_Flux.html

Citation Information - Other Details:

Salimon, C.I., E.A. Davidson, R.L. Victoria, and A.W.F. Melo. 2012. LBA-ECO ND-02 CO2 Flux from Soils in Forests and Pastures, Acre, Brazil: 1999-2001. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. http://dx.doi.org/10.3334/ORNLDAAC/1066

Keywords - Theme:

Parameter Topic Term Source Sensor
RESPIRATION BIOSPHERE ECOLOGICAL DYNAMICS FIELD INVESTIGATION IR CO2 ANALYZER
SOIL CHEMISTRY BIOSPHERE TERRESTRIAL ECOSYSTEMS LABORATORY ANALYSIS

Uncontrolled Theme Keyword(s):  CO2 FLUX, LAND COVER, LITTERFALL, SOIL CHEMISTRY, SOIL NUTRITIONAL STATUS, WESTERN AMAZONIA

Keywords - Place (with associated coordinates):

Region
(click to view profile)
Site
(click to view profile)
North South East West
  ACRE -9.77000 -9.95000 -67.07000 -67.87000

Related Publication(s):

Salimon, C.I., E.A. Davidson, R.L. Victoria, and A.W.F. Melo. (2004) CO2 flux from soil in pastures and forests in southwestern Amazonia. Global Change Biology, Vol. 10, No. 5, pp. 833-843.

Data Characteristics (Entity and Attribute Overview):

Data Characteristics:

Data are provided in three comma-delimited ASCII files:

File #1: ND02_Soil_CO2_fluxes.csv

File #2: ND02_Litter_2001-2002.csv

File #3: ND02_Soil_characteristics.csv



File contents and organization:

File #1: ND02_Soil_CO2_fluxes.csv



Col# Column heading Variable description

1 Site Sampling location. For additional information see companion file: ND02_CO2_Flux_Study_Site_Descriptions.csv

2 Month Month of the year in which measurements were taken (1 - 12), where 1=January, 2=February, etc.

3 Year Year in which measurements were taken (1999 - 2002)

4 Nutrient_class Soil nutrient class: dystropic=nutrient poor, eutropic=nutrient rich

5 Land_use Dominant land use: Pasture, Secondary forest, or Mature forest

6 Plot Plot identification number within the Humaita and Peixoto sites (1, 2, or 3)

7 Chamber_ID Chamber identification number (1 - 8 )

8 Transect_ID Transect identification code:

where the first character indicates land use (C=Secondary forest, F=Mature forest, P=Pasture);

the number in the second position indicates the research area; and

the third character indicates soil nutrient class (E=eutrophic, D=dystrophic)

9 CO2_flux Flux of CO2 from the soil to the atmosphere measured in milligrams of carbon

in the form of CO2 per meter squared per hour (mg CO2-C per m2 per h)

10 CO2_flux_SE Standard error of the CO2 flux rate calculated during the five minute sampling period

11 T_air Mean air temperature within the sampling chamber during the five minute sampling period reported in degrees Celsius



Missing data values are represented as -9999





Example data records for File #1:



Site,Month,Year,Nutrient_class,Land_use,Plot,Chamber_ID,Transect_ID,CO2_flux,CO2_flux_SE,T_air

Zoobotanical Park,6,1999,dystrophic,Secondary forest,3,1,C5D,220.96,1.96,30.5

Zoobotanical Park,6,1999,dystrophic,Secondary forest,3,2,C5D,217.99,1.26,30.53

Zoobotanical Park,6,1999,dystrophic,Secondary forest,3,3,C5D,226.99,1.79,30.6

Zoobotanical Park,6,1999,dystrophic,Secondary forest,3,4,C5D,239.67,4.05,30.6

Zoobotanical Park,6,1999,dystrophic,Secondary forest,3,5,C5D,293.11,3.83,30.7

... records intentionally omitted ...

Humaita,6,1999,eutrophic,Secondary forest,1,1,C1E,215.05,4.35,29.5

Humaita,6,1999,eutrophic,Secondary forest,1,2,C1E,320.24,12.91,29.3

Humaita,6,1999,eutrophic,Secondary forest,1,3,C1E,232.29,7.23,-9999

Humaita,6,1999,eutrophic,Secondary forest,1,4,C1E,236.34,10.61,-9999

Humaita,6,1999,eutrophic,Secondary forest,1,5,C1E,198.87,1.16,30.2

... records intentionally omitted ...

Peixoto,7,1999,dystrophic,Pasture,1,1,P1D,98.58,4.26,39.45

Peixoto,7,1999,dystrophic,Pasture,1,2,P1D,133.16,0.93,39.6

Peixoto,7,1999,dystrophic,Pasture,1,3,P1D,226.17,4.85,39.4

Peixoto,7,1999,dystrophic,Pasture,1,4,P1D,129.37,3.12,40.4

Peixoto,7,1999,dystrophic,Pasture,1,5,P1D,141.41,2.75,40.1



File #2: ND02_Litter_2001-2002.csv



Col# Column heading Variable description

1 Site Sampling location. For additional information see companion file: ND02_CO2_Flux_Study_Site_Descriptions.csv

2 Nutrient_class Soil nutrient class: dystropic=nutrient poor, eutrophic=nutrient rich

3 Land_use Dominant land use: Pasture, Secondary forest, or Mature forest

4 Transect_ID Transect identification code:

where the first character indicates land use (C=Secondary forest, F=Mature forest, P=Pasture);

the number in the second position indicates the research area; and

the third character indicates soil nutrient class (E=eutrophic, D=dystrophic)

5 Year Year in which samples were collected (2001 or 2002)

6 Month Month of the year in which samples were collected (1 - 12), where 1=January, 2=February, etc.

7 Litter_mean Mean litter mass from the 5 baskets at each site reported as grams of litter per meter squared per month (g m-2)

8 Litter_SE Calculated standard error of the mean litter mass



Missing data values are represented as -9999



Example data records:



Site,Nutrient_class,Land_use,Transect_ID,Year,Month,Litter_mean,Litter_SE

Humaita,eutrophic,Secondary forest,C1E,2001,7,121.92,16.02

Humaita,eutrophic,Secondary forest,C2E,2001,7,79.71,11.4

Peixoto,dystrophic,Secondary forest,C2D,2001,7,63.1,9.84

Zoobotanical Park,dystrophic,Secondary forest,C5D,2001,7,93.01,12.49





File #3: ND02_Soil_characteristics.csv



Col# Column heading Variable description

1 Site Sampling location. For additional information see companion file: ND02_CO2_Flux_Study_Site_Descriptions.csv

2 Nutrient_class Soil nutrient class: dystropic=nutrient poor, eutropic=nutrient rich

3 Land_use Dominant land use: Pasture, Secondary forest, or Mature forest

4 Transect_ID Transect identification code:

where the first character indicates land use (C=Secondary forest, F=Mature forest, P=Pasture);

the number in the second position indicates the research area; and

the third character indicates soil nutrient class (E=eutrophic, D=dystrophic)

5 Depth Sampling depth class: A= 0 to 5 cm, B= 5 to 10 cm, C= 20-30 cm, and D= 50 to 60 cm depth

6 Sand Percent by weight of soil particles classified as sand (diameter greater than or equal to 2 mm)

7 Silt Percent by weight of soil particles classified as silt (diameter less than 2 mm and greater than or equal to 2 um)

8 Clay Percent by weight of soil particles classified as clay (diameter less than 2 um)

9 pH Soil pH determined in a CaCl2 solution

10 SOM Soil organic matter reported in percent of total soil weight

11 P Soil phosphorus concentration (mg per kg soil)

12 K Soil potassium concentration (mg per kg soil)

13 Ca Soil calcium concentration (cmol charge per kg soil)

14 Mg Soil magnesium concentration (cmol charge per kg soil)

15 Al Soil aluminum concentration (cmol charge per kg soil)

16 H Soil hydrogen concentration (cmol charge per kg soil)

17 Sum_of_bases Sum of bases (cmol charge per kg soil): sum of measured calcium magnesium and potassium ion concentrations

18 CEC Cation exchange capacity (cmol charge per kg soil): calculated as the sum of bases plus the hydrogen ion concentration

19 Base_saturation Base saturation in percent, calculated as the sum of bases divided by cation exchange capacity



Values below the detection limit are designated as -6999





Example data records:



Site,Nutrient_class,Land_use,Transect_ID,Depth,Sand,Silt,Clay,pH,SOM,P,K,Ca,Mg,Al,H,Sum_of_bases,CEC,Base_saturation

Peixoto,dystrophic,Secondary forest,C1D,A,15,32,53,4.2,39,14,3.2,31,14,7,80,48.2,128.2,38

Peixoto,dystrophic,Secondary forest,C1D,A,12,39,49,4.2,47,12,3.2,40,13,6,109,56.2,165.2,34

Peixoto,dystrophic,Secondary forest,C1D,A,17,32,51,3.2,49,15,3.8,17,8,25,253,28.8,281.8,10

Peixoto,dystrophic,Secondary forest,C1D,B,11,30,59,3,24,12,2.7,5,4,43,313,11.7,324.7,4

Peixoto,dystrophic,Secondary forest,C1D,B,7,32,61,3.3,30,9,3.3,18,8,33,228,29.3,257.3,11

... records intentionally omitted ...

Humaita,eutrophic,Mature forest,F1E,C,19,41,40,3.2,13,4,1.6,1,3,33,166,5.6,171.6,3

Humaita,eutrophic,Mature forest,F1E,D,8,31,61,3.4,10,3,2.9,2,6,65,386,10.9,396.9,3

Humaita,eutrophic,Mature forest,F1E,D,12,25,63,3.1,12,3,2.5,1,4,65,477,7.5,484.5,2

Humaita,eutrophic,Mature forest,F1E,D,17,30,53,3.4,8,2,2.2,1,4,55,313,7.2,320.2,2

Peixoto,dystrophic,Pasture,P1D,A,16,23,61,3.9,56,10,8.2,15,10,11,121,33.2,154.2,22

Peixoto,dystrophic,Pasture,P1D,A,22,24,54,4.4,96,17,6.4,48,19,3,88,73.4,161.4,45

Peixoto,dystrophic,Pasture,P1D,A,18,22,60,4.1,69,16,5,42,15,5,121,62,183,34

Data Application and Derivation:

Carbon dioxide fluxes from pastures and forests in tropical regions are important components of the global carbon budget. These time series of soil-atmosphere gas exchange of CO2 reveal important seasonal variations in flux and provide insight to the role of soil nutrients as well as land cover in controlling CO2 fluxes from these systems.

Quality Assessment (Data Quality Attribute Accuracy Report):

Quality Assessment:

All data have been quality checked and no further changes to the data are anticipated.

Process Description:

Data Acquisition Materials and Methods:



The study areas are located in the southwestern corner of the Brazilian Amazon Basin, near the city of Rio Branco in the state of Acre, Brazil. The regional climate has a mean annual temperature of 26 degrees C; rainfall of 1940 (plus or minus 230) mm with a well-defined dry season (with less than 50mm per month from June through August); mean annual relative humidity of 85 percent(Duarte et al., 2000). The soils are classified as dystrophic and eutrophic Ultisols with patches of Oxisols (RADAMBRASIL, 1976). Natural vegetation is classified as Ombrophilous Open Forest (RADAMBRASIL, 1976) with patches of bamboo-dominated forest (Silveira, 1999). Where natural forests have been converted, 60 percent is now used for cattle ranching and agriculture, and almost 40 percent is in some stage of secondary succession.



Plots for this study were located in two secondary forests at the Zoobotanical Park (PZ) at the Federal University of Acre, Rio Branco, Acre State, and also at two government sponsored settlements: Peixoto Settlement Project and Humaita Settlement Project. In both settlements the main animal products are cattle and chickens and the principal crops are manioc, maize, banana, and rice. The four pastures studied were all between 12 and 15 years old, dominated by Brachiaria brizantha and had from zero to three burning events. The eight secondary forests were more heterogeneous in age, ranging from 3

to 18 years old, and were also diverse with respect to previous land use. The four mature forests have no historical sign of clear-cutting, but are all have been used for rubber tapping, Brazil nut extraction and for game hunting.



Soil sampling

In order to characterize soils at the Peixoto and Humaita sites, we sampled soils from each land cover to 60 cm depth. For this purpose, three soil pits(60 x 60 x 60 cm) were dug in each of the following sites: Secfor 11, Secfor 3a, Pasture 13 and Matfor at Peixoto, and in Secfor 3b, Pasture 14 and Matfor at Humaita (see associated text file for site codes and descriptions). We estimated soil bulk density by sampling twelve intact soil cores at each sampling depth using a steel cylinder 8.25cm in diameter and 6 cm in height (Blake & Hartge, 1986).



Soil temperature was measured at 10 cm depth by inserting a temperature probe near each soil respiration chamber while each flux measurement was in progress.



CO2 flux measurements

Fluxes were measured once per month from June 1999 to July 2000 at all sites, except for October when no measurement was made. Measurements were continued through January 2001 on a less regular sampling schedule. Eight CO2 flux measurements were made at each site and date. Carbon dioxide flux from soil to atmosphere was measured using an infrared gas analyzer (IRGA), LICOR-6252, coupled to a vented dynamic chamber system (Davidson et al., 2002). Eight PVC rings (20 cm diameter and 10cm height) were inserted 3 cm into the soil at each site. At the time of sampling, a PVC opaque chamber, with an inner diameter at the bottom just slightly larger than the outer diameter of the ring, was placed snugly over the ring, and air was circulated between this chamber (volume of the chamber with the top was 7.1 L) and the IRGA with an air pump at 0.5 L min_1. A vent (5cm long, 2.16mm inner diameter stainless steel tube) was installed in the chamber top through a Swaglok fitting to equalize pressure with the atmosphere. CO2 concentrations in the chamber were recorded every 12 s for 5 min and were stored in an HP 200 XL palmtop connected to the IRGA. Measurements were always conducted between nine am and two pm. The flux was calculated from linear regression of the difference of CO2 concentration over time. The first few measurements during the first minute were discarded from the regression to avoid any artifact of closing the chamber, and only the data showing a linear increase in CO2 concentration (usually during a 1-5 min interval) were used to calculate fluxes. The IRGA was calibrated every morning by using zero air that had been run through a soda lime scrubber and by using a White Martins certificated standard gas of 610 (plus or minus 2%) ppmv of CO2 (nitrogen as the balance gas).



Physical and chemical analyses were carried out at the Soil Laboratory at Escola Superior de Agronomia, following van Raij et al. (2001). Carbon concentration in soil was determined at the Isotopic Ecology Laboratory at the Centro de Energia Nuclear na Agricultura, University of Sao Paulo, using an Element Analyzer Carlo Erba, model 1110 CNHS.



Litterfall flux

Litter traps were constructed of 1 x 1m squares of 5mm nylon mesh suspended 30cm above the soil surface. Five traps were installed in each of the mature forests and in four of the secondary forests. Litter was collected monthly, stored in paper bags, sorted for removal of coarse material with diameter 45 cm, dried at 70 degrees C for 72 h, and then weighed.



References:

Blake GR, Hartge KH (1986) Bulk density. In: Methods of Soil Analysis. Part 1: Physical and Mineralogical Methods, 2 (ed. Klute A), pp. 363-376. ASA, Madison.



Davidson EA, Savage K, Verchot LV et al. (2002) Minimizing artifacts and biases in chamber-based measurements of soil respiration. Agricultural and Forest Meteorology, 113, 21-37.



Duarte AF, Artaxo Neto P, Brown IF et al. (2000) O clima em Rio Branco Acre Brasil entre os anos 1970 e 2000. Technical report to Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, Rio Branco, AC.



RADAMBRASIL (1976) Folha SC.19 Rio Branco. Ministerio das Minas e Energia, Departamento Nacional da Producao Mineral, Projeto RADAM BRASIL, Rio de Janeiro, RJ.



Silveira M (1999) Ecological aspects of bamboo-dominated Forest in southwestern Amazonia: an ethnoscience perspective. Ecotropica, 5, 213-216.



van Raij B, de Andrade JC, Cantarella H et al. (2001) Analise quimica para avaliacao da fertilidade de solos tropicais. Editora IAC, Campinas.

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