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Investigation:

ND-11 (Lehmann / Passos / Couto)

LBA Dataset ID:

lba_nd11_swp

Originator(s):

1. RENCK, A.
      2. LEHMANN, J.

Point(s) of Contact:

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

Dataset Abstract:

This data set contains information that can be used to examine water fluxes in soils beneath tree crops in an Amazonian agroforest. The data consists of repeated measurements of soil matrix pressure and soil moisture content at several depths. The study was carried out at the Empresa Brasileira de Pesquisa Agropecuaria (Embrapa)-Amazonia Ocidental, 29 km North of Manaus, Brazil (3 deg. 8' S, 59 deg. 52' W, 40 - 50 m above sea level), in 1998 and 1999. Microaggregated tropical soils have shown high water conductivity even under unsaturated conditions in laboratory experiments. It is not clear, however, what depth the infiltrating soil water reaches during storm events under humid tropical conditions. Dynamics and fluxes of water were determined with high temporal resolution to a depth of 5 m in a Xanthic Hapludox of central Amazonia, Brazil. The soil water percolated to a depth of 0.9 m within 2 h of a rainfall event of 48 mm. Water fluxes were significantly slower below 0.9 m (17% of infiltration at 0 - 0.9 m) due to higher bulk densities. Percolation not only started rapidly after a rainfall event when soil water suction reached a certain threshold (ca. 20 - 30 hPa) but was also reduced to background levels less than 1 h after the rain had ended. The demonstrated extremely short-term dynamics of water fluxes have implications for measurement design of water availability and solute leaching in microaggregated tropical soil that require correct time integrals of solution concentrations and soil water dynamics. Measurement intervals of 30 min or less were necessary in our study. Rapid water flows may explain the observed high nutrient losses from the topsoil of microaggregated tropical soil and the large accumulation of nutrients in the deep soil (> 5 m).

Beginning Date:

1998-01-01

Ending Date:

1999-12-31

Metadata Last Updated on:

2007-09-19

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-11 Soil Water Pressure and Flow Measurements under Tree Crops:  http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=851

Documentation/Other Supporting Documents:

LBA-ECO ND-11 Soil Water Pressure and Flow Measurements under Tree Crops:  http://daac.ornl.gov/LBA/guides/ND11_Soil_Water_Pressure.html

Citation Information - Other Details:

Renck A. and J. Lehmann. 2007. LBA-ECO ND-11 Soil Water Pressure and Flow Measurements under Tree Crops.Data Set. Available on-line [http://www.daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/851

Keywords - Theme:

Parameter Topic Term Source Sensor
SOIL MATRIC PRESSURE AGRICULTURE SOILS FIELD INVESTIGATION TENSIOMETER
SOIL MOISTURE/WATER CONTENT AGRICULTURE SOILS FIELD INVESTIGATION TIME DOMAIN REFLECTOMETER
SOIL WATER PRESSURE AGRICULTURE SOILS FIELD INVESTIGATION TENSIOMETER

Uncontrolled Theme Keyword(s):  AGGREGATION, AMAZON, BYPASS FLOW, HUMID TROPICS, LEACHING, MATRIC PRESSURE, SOIL WATER PRESSURE

Keywords - Place (with associated coordinates):

Region
(click to view profile)
Site
(click to view profile)
North South East West
Amazonas (Manaus) EMBRAPA DAS EXPERIME -3.13470 -3.13470 -59.88000 -59.88000

Related Publication(s):

Renck A. and J. Lehmann. 2004. Rapid water flow and transport of inorganic and organic nitrogen in a highly aggregated tropical soil. Soil Science 169(5):330-341.

Data Characteristics (Entity and Attribute Overview):

Data Characteristics:

<p class=i2>One comma-delimited ASCII file is provided.

Values of -9999 in the ASCII file indicate missing values.</p><blockquote><p class=i2>Soil_Water.csv</b> </p></blockquote><p class=i2>One Excel file is provided.

Missing values are indicated by blank cells.</p><blockquote><p class=i2>Soil_Water.xls</b></p></blockquote><p class=i2>Both files have the same contents. The files provide soil matrix pressure (negative values denote tension) and soil moisture data at depth below tree species</p><blockquote><p class=i2>Example Records from Soil_Water.csv:</b></p><table border=2 width=61% id=table1 bgcolor=#D7EBFF><tr><td>"""File Name: Soil_Water.csv"""<p>"""File Contents: This file provides soil matrix pressure (negative values denote tension) and soil moisture data at depth below tree species."""</p><p>"""Values of -9999 in ascii file indicate missing values."""</p><p>"""----Column 1: Tree species name: Values include:"""
"""------------cup=cupuacu=Theobroma grandiflorum (Willd. ex Spreng.) K. Schum"""
"""------------puer=Pueraria phaseoloides (Roxb.) Benth. (Pueraria)"""
"""------------pup=pupunha=Bactris gasipaes Kunth."""
"""------------urucum=Bixa orellana L. (annatto)"""
"""----Column 2: Day (DD)"""
"""----Column 3: Month (MM)"""
"""----Column 4: Year (YY)"""
"""----Column 5: Soil matrix pressure at 10cm depth, (hPa)"""
"""----Column 6: Soil matrix pressure at 30cm, (hPa)"""
"""""---Column 7: Soil matrix pressure at 90cm, (hPa)"
"""----Column 8: Soil matrix pressure at 150cm, (hPa)"""
"""""---Column 9: Soil matrix pressure at 250cm, (hPa)"
"""----Column 10: Soil matrix pressure at deepest measurement point """,,,,,,,,,,,,,,
"""------------ Deepest for pup = 500cm""",,,,,,,,,,,,,,
"""------------ Deepest for cup = 400cm""",,,,,,,,,,,,,,
"""------------ Deepest for puer = 400cm""",,,,,,,,,,,,,,
"""----Column 11: Soil moisture at 10cm, volumetric water content (%)""",,,,,,,,,,,,,,
"""----Column 12: Soil moisture at 30cm, volumetric water content (%)""",,,,,,,,,,,,,,
"""----Column 13: Soil moisture at 90cm, volumetric water content (%)""",,,,,,,,,,,,,,
"""----Column 14: Soil moisture at 150cm, volumetric water content (%)""",,,,,,,,,,,,,,
"""----Column 15: Soil moisture at 250cm, volumetric water content (%)""",,,,,,,,,,,,,,</p><p>Tree spp,Day,Month,Year,Matrix pressure at 10cm,Matrix pressure at 30cm,Matrix pressure at 90cm,Matrix pressure at 150cm,Matrix pressure at 250cm,Matrix pressure at deepest,Soil moisture at 10cm,Soil moisture at 30cm,Soil moisture at 90cm,Soil moisture at 150cm,Soil moisture at 250cm
pup,29,9,98,-159,-433,-174,0,-137,-9999,-9999,-9999,-9999,-9999,-9999
pup,1,10,98,-264,-740,-223,0,-133,-9999,-9999,-9999,-9999,-9999,-9999
pup,6,10,98,-250,-720,-200,0,-130,-9999,-9999,-9999,-9999,-9999,-9999
...</td></tr></table></blockquote><p class=i2>

Data Application and Derivation:

Data set contains results from a field study of water fluxes within agroforest soils.

Quality Assessment (Data Quality Attribute Accuracy Report):

Quality Assessment:

No known problems with data.

Process Description:

Data Acquisition Materials and Methods:

The study was carried out at the Empresa Brasileira de Pesquisa Agropecuaria (Embrapa)- Amazonia Ocidental, 29 km North of Manaus, Brazil, in 1998 and 1999. The rainfall distribution is unimodal, with maximum rainfall between December and May (211�300 mm per month; 75% of annual rainfall) and mean annual precipitation of about 2500 mm, air temperature of 26 degree C, and atmospheric humidity about 84%. The vegetation is a tropical lowland rainforest. The soils are Xanthic Hapludox, which are derived from Tertiary sediments. They are very deep and clayey, with low pH and medium levels of organic C and N.



Water fluxes were investigated in a multi-strata agroforestry system with Theobroma grandiflorum (Willd. ex Spreng.) K. Schum. (cupuacu); Bactris gasipaes Kunth. (peach palm); Bertholletia excelsa Humb. & Bonpl. (Brazil nut); and Bixa orellana L. (annatto), and a legume cover of Pueraria phaseoloides (Roxb.) Benth. (pueraria).



Each replicate tree in the three plots was equipped with time domain reflectometry sensors (TDR, EASY TEST®, Lublin, Poland; mounted on shafts) at soil depths of 0.1, 0.3,0.9, and 1.5 m. Suction cups were installed in duplicate at 0.1-, 0.6-, and 2.0-m depths. In 1996, holes for all instruments were prepared using an auger of the same diameter as the shafts and filled with a slurry using the soil material to provide optimum contact. The instruments were inserted at an angle of 25 degrees in a radius of 1 m around the stems, and rubber discs were installed around the tubes on the soil surface to prevent preferential flow along the shafts. In addition, one soil pit was dug to a depth of 3 m in 1997 and equipped horizontally with TDR sensors at depths of 0.1, 0.3, 0.9, 1.5, and 2.5 m, with tensiometers at depths of 0.1,0.3,0.9, 1.5, 2.5, 4.0, and 5.0 m, and with suction cups at depths of 0.1, 0.6, 1.2, 2.0, 3.0, and 4.0 m for the pueraria, cupuacu, and peach palm, respectively (one sensor or sampler per depth and position). The cups were made of Al2O3 (70%) and SiO2 (29%), with an average pore size of 1 um (UMS, Munich, Germany). TDR sensors were read with a hand-held meter (EASY TEST®, Lublin, Poland), and vacuum in the headspace of the tensiometers was measured by inserting a needle through a rubber septum (UMS, Munich, Germany). TDR readings were transformed into volumetric water contents using field calibrations in the same soil (Teixeira, 2001).



The rate of water percolation in the soil profile was estimated by calculating the time that was required for the soil water suction to reach a local minimum at a given depth after a rainfall event. This time was called retardation time. The onset of soil water percolation at the upper boundary was set as the time when the soil water suction at a depth of 0.1 m decreased by 10% or more. Soil water and nutrient leaching was obtained by two different approaches: the gradient method using Darcy�s equation and water balance. For the gradient method, soil water suction was obtained from the installed tensiometers. The saturated hydraulic conductivity was obtained from disc infiltrometers and laboratory experiments (constant-head) in adjacent soils.

References:

Renck A. and J. Lehmann. 2004. Rapid water flow and transport of inorganic and organic nitrogen in a highly aggregated tropical soil. Soil Science 169(5):330-341.

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