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SGP99 Soil Surface Bulk Density Sampling Desults
The results obtained from sampling the soil surface layer
(0-5 cm) bulk density are provided. For interpretation of codes
used for areas and sites please refer to the experiment plan.
Field notebooks are available for use at the USDA Hydrology
Lab, they will not be loaned out. Also included in this
information file is the background material from the sampling
plan describing the design and protocols used.
Two levels of data files are available, the
summary (means and standard deviations of all
sites) and the raw data. Files are all ASCII
text. The data contained in these files is as follows
Summary
| Filename |
bd99sum.txt |
| Format |
ASCII text table |
| Column
Headings |
Area ID |
| Site ID |
| Date (Month-Day-Year) |
| Mean Bulk Density(g/cm3) |
| Standard Deviation of Bulk Density
(g/cm3) |
| Cover |
| Note (if any) |
Raw Data
| Filename |
bd99raw.txt
(LIMITED DISTRIBUTION) |
| Format |
ASCII text table |
| Column
Headings |
Area ID |
| Site ID |
| Replication |
| Date (Month-Day) |
| Start Volume(ml) |
| End Volume (ml) |
| Total Volume (ml) |
| Wet Weight (g) |
| Dry Weight (g) |
| Volume of Water (ml) |
| Gravimetric Soil MoistureBulk Density
(g/cm3) |
| Note (if any) |
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Sampling
Plan
Bulk density is used to convert the gravimetric samples to
volumetric soil moisture. A volume extraction technique was
used. In general, four samples per site were taken.
In addition to the samples collected as described below, a
team from Oklahoma State University collected profile core
samples of gravimetric soil moisture. Using this technique it
is possible to estimate the bulk density. The average 0 to
5-cm soil layer values at the sites they sampled are included
in the summary and are described as profile results.
Protocol
Only a brief summary is provided. Please see the
experiment plan for details. After selecting a location,
vegetation is removed. A volume of surface soil is extracted
to a specific depth (5-cm). Using the volumes extracted and
the dry weight of the soil extracted, the bulk density is
computed. The computation is as follows
- Compute volume of soil extracted: Volume Total = Volume
End - Volume Start
- Compute dry soil mass extracted: sample dry weight -
tare
- compute bulk density: dry soil mass extracted/soil
volume extracted
- Note that the data presented in the tables have had the
tare weights removed. It is also possible to compute the
soil moisture of the sample used for the bulk density
- Gravimetric soil moisture: (wet weight - dry weight) /
dry weight
FTP Site
The Soil Bulk Density Summary File from SGP99 resides on
DAAC anonymous FTP. You may access it from this document,
 Summary
file (ASCII)
- or directly via FTP at
- ftp disc.gsfc.nasa.gov
- login: anonymous
- password: < your internet address >
- cd /data/sgp99/soil_properties/BulkDen
The Soil Bulk Density raw data files from SGP99 are for
limited distribution only. To obtain them, contact Principal Investigator Thomas Jackson
at the Agricultural Research Service Hydrology Lab (see
"Points of Contact below.")
Points of
Contact
The Principal Investigator for the SGP99 Soil Bulk Density
data, and the point of distribution for the raw data files
is
Thomas J. Jackson
USDA ARS Hydrology Lab
Bldg. 007, Rm. 104, BARC-West
Beltsville, MD 20705
tjackson@hydrolab.arsusda.gov
301-504-8511 (voice)
For information about or assistance in using SGP99 DAAC
data, contact
Hydrology Data Support Team
EOS Distributed Active Archive Center (DAAC)
Code 610.2
NASA Goddard Space Flight Center
Greenbelt, Maryland 20771
hydrology-disc@listserv.gsfc.nasa.gov
301-614-5165 (voice)
301-614-5268 (fax)
Last Updated:Thu Oct 28 09:44:26 EDT 2004
Page Author: Hydrology Data Support Team -- hydrology-disc@listserv.gsfc.nasa.gov
Web Curator: -- Website Curator:
NASA official: Steve Kempler, DAAC Manager -- Steven.J.Kempler@nasa.gov
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Soil Moisture