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LBA-ECO ND-10 Soil Properties of Pasture Chronosequences, Para, Brazil: 1997

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Revision date: June 24, 2013

Summary:

This data set provides the results of soil physical property and chemical measurements of samples collected from two pasture chronosequences (years since conversion from primary forest) located on two ranches south of Santarem, Para, Brazil, and east of the Tapajos River. Soil data includes soil classification, bulk density, texture, and mean concentrations of total nitrogen (N), carbon (C), phosphorus (P), and P fractions. The soils were high clay oxisols and highly sandy entisols.

One chronosequence of sites was established on oxisol soils dating 2, 7, and 15 years since conversion from primary forest. A second set of sites, 1, 7, and 15 years old, was established on the sandy entisols. Five of the six pasture sites were on a single ranch; the 2-year-old oxisol pasture was the exception. Ten soil samples per site were collected from 0-10 cm depth along random intervals within 100-m transects in August 1997.

There are two comma-delimited (.csv) data files with this data set.

 

Data Citation:

Cite this data set as follows:

Asner, G.P., A.R. Townsend, and M.M.C. Bustamante. 2013. LBA-ECO ND-10 Soil Properties of Pasture Chronosequences, Para, Brazil: 1997. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA. http://dx.doi.org/10.3334/ORNLDAAC/1171

Implementation of the LBA Data and Publication Policy by Data Users:

The LBA Data and Publication Policy [http://daac.ornl.gov/LBA/lba_data_policy.html] is in effect for a period of five (5) years from the date of archiving and should be followed by data users who have obtained LBA data sets from the ORNL DAAC. Users who download LBA data in the five years after data have been archived must contact the investigators who collected the data, per provisions 6 and 7 in the Policy.

This data set was archived in June 2013. Users who download the data between June 2013 and May 2018 must comply with the LBA Data and Publication Policy.

Data users should use the investigator contact information in this document to communicate with the data provider.

Data users should use the Data Set Citation and other applicable references provided in this document to acknowledge use of the data.

Table of Contents:

1. Data Set Overview:

Project: LBA (Large-Scale Biosphere-Atmosphere Experiment in the Amazon)

Activity: LBA-ECO

LBA Science Component: Nutrient Dynamics

Team ID: ND-10 (Townsend / Asner / Bustamante)

The investigators were Asner, Gregory Paul; Townsend, Alan R. and Bustamante, Mercedes M.C. You may contact Asner, Gregory P. (greg@globalecology.stanford.edu); Townsend, Alan R. (Alan.Townsend@colorado.edu) and Bustamante, Mercedes M.C. (mercedes@unb.br).

LBA Data Set Inventory ID: ND10_Soil_Chemistry

This data set provides the results of soil physical property and chemical measurements of samples collected from two pasture chronosequences (years since conversion from primary forest) located on two ranches south of Santarem, Para, Brazil, and east of the Tapajos River. Soil data includes soil classification, bulk density, texture, and mean concentrations of total nitrogen (N), carbon (C), phosphorus (P), and P fractions. The soils were high clay oxisols and highly sandy entisols.

One chronosequence of sites was established on oxisol soils dating 2, 7, and 15 years since conversion from primary forest. A second set of sites, 1, 7, and 15 years old, was established on the sandy entisols. Five of the six pasture sites were on a single ranch; the 2-year-old oxisol pasture was the exception. Ten soil samples per site were collected from 0-10 cm depth along random intervals within 100-m transects in August 1997.

 

2. Data Characteristics:

There are two comma-delimited data files with this data set.

File 1. ND10_tapajos_pasture_soil_chemistry.csv

ColumnHeadingUnits/format Description
1Soil_order  Soil order either Oxisol or Entisol
2AgeY Age of the pasture at the time of sampling in years
3Sand % Percent of soil mass classified as sand particles
4Silt% Percent of soil mass classified as silt particles
5 Clay% Percent of soil mass classified as clay particles
6 pH   Soil pH
7Total_C_conc% Mean soil C concentration reported in percent (%). Total C was determined on a combustion reduction elemental analyzer
8Total_C_stderr% Standard error of the mean soil C concentration, N of 10 samples per site
9Total_N_conc % Mean soil N concentration reported in percent (%). Total N was determined on a combustion reduction elemental analyzer
10Total_N_stderr  Standard error of the mean soil N concentration, N of 10 samples per site
11 Total_P_conc ug/g Mean soil P concentration reported in micrograms P per gram of soil (ug/g). Total P was determined using a sulfuric acid digest see methods for details
12 Total_P_stderr   Standard error of the mean soil P concentration, N of 10 samples per site
13Bulk_density g/cm3 Soil bulk density reported in grams per centimeter cubed (g/cm3)
14Total_C_pool kg/m2 Mean soil C pool in the 0 to 10 cm depth calculated from measured soil C concentration (Col 5) and bulk density (Col 8) and reported in kilograms C per meter squared (kg/m2)
15Total_N_pool kg/m2 Mean soil N pool in the 0 to 10 cm depth calculated from measured soil N concentration (Col 7) and bulk density (Col 8) and reported in kilograms N per meter squared (kg/m2)
16Total_P_pool g/m2 Mean soil P pool in the 0 to 10 cm depth calculated from measured soil P concentration and bulk density (Col 8) and reported in grams P per meter squared (g/m2)

Example records:

Soil_order,Age,Sand,Silt,Clay,pH,Total_C_conc,Total_C_stderr,Total_N_conc,Total_N_stderr,Total_P_conc,Total_P_stderr,
Bulk_density,Total_C_pool,Total_N_pool,Total_P_pool
Oxisol,2,37,3,60,5.3,4.35,0.1,0.32,0.02,173.8,14.8,1.2,5.2,0.4,20.9
Oxisol,7,39,2,59,5.4,2.28,0.04,0.19,0.01,135.8,6.7,1.5,2.7,0.2,16.3
...
Entisol,7,92,2,5,5.6,1.54,0.2,0.09,0.04,52.3,4.3,1.4,2.2,0.1,7.5
Entisol,15,91,4,5,5.3,1.4,0.04,0.08,0.01,45.2,2.1,1.4,2,0.1,6.5

File 2. ND10_tapajos_pasture_P_fractions.csv

ColumnHeading Units/format Description
1Soil   Soil order either oxisol or entisol
2Age Y Pasture age in years at the time of sampling
3P_fraction Pi or PoName of the fraction labeled according to extractant (NaOH, HCL, Resin, Bicarb, Residual, or Sum of fractions) in the modified Hedley technique. The appended "_Pi" indicates inorganic P and the appended "_Po" indicates organic P
4Mean_conc ug/g Concentration of P reported in micrograms P per gram of soil (ug/g)
5Std_err_conc ug/g Standard error of the mean concentration reported in micrograms of P per gram of soil (ug/g). N= 8 for all

Example records:

Soil,Age,P_fraction,Mean_conc,Std_err_conc
Oxisol,2,Resin_Pi,8.6,3.5
Oxisol,2,Bicarb_Pi,2.9,1.7
...
Oxisol,15,Sum of fractions,139.7,4.4
Entisol,1,Resin_Pi,6.8,1.2
...
Entisol,15,Residual,9.6,0.8
Entisol,15,Sum of fractions,39.6,1.5

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

Site (Region) Westernmost Longitude Easternmost Longitude Northernmost Latitude Southernmost Latitude Geodetic Datum
Ranch Pasture Site (1): Para Western (Santarem) (Para Western (Santarem))  Basins) -54.666 -54.666-3.1333-3.1333 World Geodetic System, 1984 (WGS-84)
Ranch Pasture Site (2): Para Western (Santarem) (Para Western (Santarem)) -54.933 -54.933-3.2666 -3.2666 World Geodetic System, 1984 (WGS-84)

Time period:

Platform/Sensor/Parameters measured include:

3. Data Application and Derivation:

Land-use-driven changes in P availability may be central to predicting the sustainability of cleared land, as well as land-atmosphere exchanges of carbon and trace gases following forest conversion.

Soil P losses after deforestation may be an indicator for long-term productivity after cleared lands are abandoned.

 

4. Quality Assessment:

Statistical analyses of differences among sites and along each chronosequence were performed using the one-way ANOVA procedure in SPSS v.10.0 (SPSS Inc., Chicago, Illinois). Where significant trends were found, further analyses of differences between each site were evaluated using the same software to perform a post hoc Tukey’s HSD test.

 

5. Data Acquisition Materials and Methods:

Site Description:

The research sites consisted of two pasture chronosequences (years since conversion from primary forest) located on two ranches south of Santarem, Para, and east of the Tapajos River. Mean annual rainfall is 2,000 mm, the bulk of which occurs between January and May, and mean annual temperature is 25 degrees C. All sites are on upland terra firma that has pockets of relic depositional surfaces, creating a mix of high clay oxisol sand highly sandy entisols (Asner et al., 1999).

One chronosequence of pastures was established on the oxisols dating 2, 7, and 15 years since conversion, and a second trio of sites (1, 7, and 15 years old) was established on the sandy entisols.  Five of the six pastures were on a single ranch; the 2-year-old oxisol pasture was the exception. Three of the sites (1-year entisol , 2-and 7-year oxisols) were dominated by the pasture grass Brachyaria brizantha. The 15-year clay and sand sites and the 7-year sand pasture were dominated by the grass, Pennesetum clandestinum. All pastures were formed from primary forest. Some woody invaders, notably Solanum paniculatum, were sparsely distributed in some of the sites. All but the two youngest pasture sites had been burned since conversion as a means of controlling woody pioneer species, with one post-clearing burn in each of the two 7-year-old pastures, and two such burns in the two oldest pastures. The two youngest pastures in each sequence had not yet been grazed. Relief in all sites was minimal, and none of the pastures had been fertilized (Townsend et al., 2002).

Soil Collections and Analyses (from Townsend et al., 2002)

Ten soil samples per site were collected from 0-10 cm depth along random intervals within 100-m transects, air dried, and sieved at 2 mm and analyzed for pH, texture (percent sand, silt, or clay). Total C, N, P, and P fraction were determined according to the following:

 Total C, N, and  P analyses:

 Bulk density:

 P fractions: Approximately 1 g of soil from eight of the ten cores was analyzed for soil P fractions using the modified Hedley fractionation technique described by Tiessen and Moir (1993) (Fig.2):

diagram of hedley process

Figure 2. Diagram of  sequential P extraction process. Pi = inorganic P, Po=organic P, Pt=total P (Tiessen and Moir, 1993).

The one exception to the method above was that all fractions were analyzed on an Alpkem autoanalyzer, and rather than titrating each fraction by hand as described in Tiessen and Moir (1993), the normality of the color reagent for the Alpkem was adjusted to create the desired acidity at the detector for each separate P fraction. Tests showed no significant differences between this analytical method and the traditional, more time-consuming hand titration approach.

 

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:
E-mail: uso@daac.ornl.gov
Telephone: +1 (865) 241-3952

7. References:

Asner, G.P., Townsend, A.R., and Bustamante, M.M.C. 1999. Spectrometry of pasture condition and biogeochemistry in the Central Amazon. Geophysical Research Letters 26(17): 2769-2772.

Tiessen, H. and J. O. Moir. Characterization of available P by sequential extraction. In M. R. Carter, (Ed.), Soil Sampling and Methods of Analysis. Boca Raton, Lewis Publishers. 1993.

Townsend, A.R., G.P. Asner, C.C. Cleveland, M.E. Lefer, and M.M.C. Bustamante. (2002) 37. Journal of Geophysical Research-Atmospheres 107(D20).

Veldkamp, E., Organic carbon turnover in three tropical soils under pasture after deforestation, Soil Sci. Soc. Am. J., 58, 175-180, 1994.

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