[Parameters: Topic='AGRICULTURE', Term='SOILS', Variable_Level_1='NITROGEN', Detailed_Variable='TOTAL NITROGEN']
Calhoun Experimental Forest Soil Carbon StudyEntry ID: DU.CalhounForest
Abstract: This experiment began in 1962. The site history was a)pre-1800:
Eastern North American deciduous forest; b)1800-1957:
cotton,corn,wheat,pasture. The site was converted to forest in 1957,
and the "time zero" sample was taken in 1962 from 16 permanent plots
at depths 0-7.5,7..5-15,15-35,35-60 cm. ALL samples from time zero are
archived at Duke University.
MEASUREMENTS MADE DURING THE EXPERIMENT
... a) Vegetation measurements made and frequency
1-Total above-ground dry matter: Approx every 5 years.
2-Above & Below-ground biomass and forest floor. Biomass estimated
via allometry is measured approximately every five years. Estimates of
nutrient contents are made based on nutrient sampling in
1990. Forest floor (O horizon) measured only in 1992, complete with
b) Soil sampling
Time zero soil measurements taken.
Details of soil sampling method: Eight of the 16 permanent plots
are resampled every 5 or 6 years. From each plot, a 2 cm diameter
punch tube is used to collect "at least 20" individual samples per
plot. Areas of the eight repeated-sample plots are 0.03 and 0.06 ha (4
plots each). Samples are taken with a stratified RANDOM collection
from within the plot.Soil is separated into layers. Details of
measuring depths and soil layers: 0-7.5,7.5-15,15-35,35-60 cm:
1962,68,72,77,82,90. 60-800 cm samples are taken from 16 layers that
were collected only in 1992-94.
c) Soil measurements made and frequency
Total carbon: 1962,1968, 1977, 1982, 1990
Method of measuring total carbon: CHN analyzer, dry combustion. Wet
Biomass carbon: 50% of biomass, to be corrected 1995-96
Method of measuring biomass carbon: Sampling of biomass components
and CHN analyzer.
Carbon dioxide evolution: 2 or 3 weeks/>2 yr
Method of measuring carbon dioxide evolution: From 4 or 8 of the
permanent plots, 10 sites are measured for CO2 evolution per plot
every 2 or 3 weeks. Infrared detector (PP system) is used to measure
efflux. Also CO2 Depth Profile. Measurements are also made of CO2 and
Rn222 concentrations of soil atmosphere reservoirs placed between 7.5
and 600 cm depth.
Total nitrogen: 1962,68,72,77,82,90
Method of measuring total nitrogen: CHN- and Kjeldahl-N
Soil bulk density or weight: 1990 (only in detailed study of
Method of measuring soil bulk density or weight: From 3 faces of
4 large soil pits, 6cm diameter Bulk Density sampler was used TWICE on
Other nutrients: Soil solutions have been collected and analyzed
per 117. below.
Atmospheric inputs: Wet-only and bulk deposition has been collected
and analyzed for DOC and all major ions
(H,NH4,Ca,Mg,K,Na,Cl,NO3,SO4,HCO3) every 2 weeks for more than two
years. Soil solutions (0 horizon, 0.15,0.6,1.75,4 and 6 m) and canopy
throughfall have been collected and analyzed from the eight permanent
plots for more than two years.
Other measurements: 1. Gas Rn-222 measured at the same depths as
CO2 to estimate efflux of CO2 via Fick's equations. 2. Plant (tree)
and forest floor accumulations of nutrients, Si, +Al have been
measured to evaluate biomass accumulations by the post-agricultural forest.
d) Details of the meteorological station
Nearest meteorological station to the site: A composite of on-site and
nearby (<25 km) stations are used.
The meteorological station is automatic.
e) Meteorological data available and frequency
Air temperature: Daily
Soil temperature: Every 3 weeks at 15 cm depth
Wind speed: Daily
Net Radiation: Daily
Relative humidity: Daily
Potential evapotranspiration: Daily measured/calculated by PROSPER
hydrologic model of Goldstein,
Luxmoore, Huff, Vose and Swank. A process, daily time step model of
evapotranspiration and soil drainage.
f) Isotope measurements available and frequency
Total soil carbon 14 measurements: 1962, 1968, 1972, 1977, 1982, 1990
Carbon dioxide carbon 14 measurements: Pending
Details of isotope measurements: Richter et al (1994) North Am. Forest
Soils Conf. 8th.
g) Archived samples available
Archived soil samples: Six times dating from 1962
Other archived samples available: Rain, throughfall, soil solutions
every 2 weeks 1992-1994.
This information was compiled for the GCTE-SOMNET Database, Pete
Smith, Pete Falloon, David Powlson, and Jo Smith. Soil Science
Department, IACR-Rothamsted, UK.
Data Set Citation
Dataset Originator/Creator: Richter, D.D. and D. Markewitz
Dataset Title: The Calhoun Experimental Forest
Dataset Series Name: Understanding Soil Change : Soil Sustainability over Millennia, Centuries, and Decades
Dataset Release Date: 2001
Dataset Publisher: Cambridge University PressOnline Resource: http://calhoun.env.duke.edu/
Start Date: 1962-01-01
Vertical Resolution: 7cm
Temporal Resolution: varies by measurement
AGRICULTURE > FOREST SCIENCE > FOREST MANAGEMENT
AGRICULTURE > FOREST SCIENCE > FOREST YIELDS
AGRICULTURE > SOILS > CARBON > CARBON DIOXIDE
AGRICULTURE > SOILS > CARBON > TOTAL CARBON
AGRICULTURE > SOILS > NITROGEN > TOTAL NITROGEN
AGRICULTURE > SOILS > ORGANIC MATTER
AGRICULTURE > SOILS > SOIL BULK DENSITY
AGRICULTURE > SOILS > SOIL FERTILITY
AGRICULTURE > SOILS > SOIL GAS/AIR > RN-222
AGRICULTURE > SOILS > SOIL PH
AGRICULTURE > SOILS > SOIL RESPIRATION
AGRICULTURE > SOILS > SOIL TEMPERATURE
BIOSPHERE > VEGETATION > BIOMASS
BIOSPHERE > VEGETATION > CANOPY CHARACTERISTICS
BIOSPHERE > VEGETATION > CARBON
BIOSPHERE > VEGETATION > FOREST COMPOSITION/VEGETATION STRUCTURE
BIOSPHERE > VEGETATION > LITTER CHARACTERISTICS
LAND SURFACE > SOILS > CARBON > CARBON DIOXIDE
LAND SURFACE > SOILS > ORGANIC MATTER
LAND SURFACE > SOILS > SOIL BULK DENSITY
LAND SURFACE > SOILS > SOIL FERTILITY
LAND SURFACE > SOILS > SOIL GAS/AIR > RN-222
LAND SURFACE > SOILS > SOIL PH
LAND SURFACE > SOILS > SOIL RESPIRATION
LAND SURFACE > SOILS > SOIL TEMPERATURE
Quality There are at least 8 replicates in the experiment. The experiment has
a randomized plot design. There are control plots described as
follows: In 1992-93 a set of sample plots were established within 10
km of the Calhoun Experimental Forest. Soils were derived from the
same soil series as the Calhoun, but supported 40-50 yr ... pine, old
uneven aged hardwood, pasture or row (arable) crops. All of these
plots have been sampled and analysed for total soil C, N and many
other soil properties. The intent was to give a restricted
control. See Richter et al (1994) Proceedings of the Eigth North
American Forest Soils Conference. We believe in not removing data
from the data set if there are no analytical reasons to suspect the
quality of the analysis. More than 95% of soil samples are archived,
so old total N, C, Ca, Mg, K data have been checked with new
analyses. See Richter et al (1994) Ecology, 75 no. 5.
Access Constraints none
Use Constraints Link to the following location to view data use policy of SOMNET members:
Richter, D.D. & Markewitz, D. (1995a) How deep is the soil ?
Richter, D.D. & Markewitz, D. (1995b) Carbon changes during the growth
of loblolly pine on fromerly cultivated soil: The Calhoun Experimental
Forest. In: Evaluation of soil organic matter models using existing
long-term datasets (ed: D.S. Powlson, P. Smith & J.U. Smith), NATO ASI
Series I, Volume 38, Springer-Verlag, Heidelberg: 397-409.
Richter, D.D., Markewitz, D., Duscombe, J.K., Heine, P.R., Wells,
C.G., Staunes, A., Allen, H.L., Urrego, B., Harrison, K. & Bonani,
G. (1994a) Carbon cycling in a loblolly pine forest: Implications for
the missing carbon sink and for the concept of soil. Proceedings of
the Eighth North American Forest Soils Conference, Gainesville, Soil
Science Society of America: 233-251
Richter, D.D., Markewitz, D., Wells, C.G., Allen, H.L., April, R.,
Heine, P.R. & Urrego, B. (1994a) Soil chemical change during three
decades in an old-field loblolly pine (Pinus taeda L.)
ecosystem. Ecology 75: 1463-1473.
Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date: 1999-09-20
Last DIF Revision Date: 2016-11-18
Future DIF Review Date: 2001-09-20