Difference between revisions of "Soil moisture - TDR (TRIME tube access probe)"
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[[Image: Trime_access_tube_probe.jpg |right|300px|]] | [[Image: Trime_access_tube_probe.jpg |right|300px|]] | ||
==Parameter to be measured:== | ==Parameter to be measured:== | ||
− | Soil moisture after the method of Stacheder (1996) calibration is necessary | + | Soil moisture after the method of Stacheder (1996) with an effective penetration depth of the probe T3 about 15 cm, of T3C 10 cm, calibration is necessary |
==Method:== | ==Method:== | ||
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==Equipment:== | ==Equipment:== | ||
− | *IMKO | + | *IMKO-T3 or IMKO-T3C for more saline soils access tube probe with cable and IMKO TRIME-FM3 standard field measuring device |
==Advantages:== | ==Advantages:== | ||
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==Disadvantages:== | ==Disadvantages:== | ||
*installation of access tube in gravel rich soils is complicated and the IMKO drill is useless in this soils. | *installation of access tube in gravel rich soils is complicated and the IMKO drill is useless in this soils. | ||
+ | *there is no marking on the cable to control the direction of the probe, measurment in different directionts has to be done carefully | ||
==What to watch out for:== | ==What to watch out for:== |
Revision as of 15:53, 17 December 2008
Parameter to be measured:
Soil moisture after the method of Stacheder (1996) with an effective penetration depth of the probe T3 about 15 cm, of T3C 10 cm, calibration is necessary
Method:
Trime TDR-method (IMKO, 2000)
Equipment:
- IMKO-T3 or IMKO-T3C for more saline soils access tube probe with cable and IMKO TRIME-FM3 standard field measuring device
Advantages:
- easy and fast measurement in access tube to the depth of the access tube
- manual as well as continuously logged measurements possible, but if logged measurement only in one depth
- accuracy comparable to neutron probes
Disadvantages:
- installation of access tube in gravel rich soils is complicated and the IMKO drill is useless in this soils.
- there is no marking on the cable to control the direction of the probe, measurment in different directionts has to be done carefully
What to watch out for:
- The measurement volume of the probe is not circularly around the probe. To measure the mean water content of one depth requires measurement in different directions.
Problems/Questions:
Links
Other related web sites:
- IMKO: [1]
References
Evett, SR, Tolk, JA, Howell, TQ 2006. Soil profile water content determination: Sensor accuracy, axial response, calibration, temperature dependence, and precision. Vadose Zone 5, 894–907.
Imko GmbH, 2000. Theoretical Aspects on Measuring Moisture Using TRIME. http://www.imko.de/ENG/filebase/Publications/TRIME-THEORY.pdf
Laurent, J-P, Ruelle, P, Delage, L, Zairi, A, Nouna, BB, Adjmi, T 2005. Monitoring Soil Water Content Profiles with a Commercial TDR System: Comparative Field Tests and Laboratory Calibration. Vadose Zone Journal 4, 1030–1036.
Laurent, J-P and Evett, SR 2008. TRIME® FM3 MOISTURE METER AND T3 ACCESS TUBE PROBE, in: INTERNATIONAL ATOMIC ENERGY AGENCY, Field Estimation of Soil Water Content A Practical Guide to Methods, Instrumentation and Sensor Technology [2]
Stacheder, M, 1996. Die Time Domain Reflectometry in der Geotechnik, Messung von Wassergehalt, elektrischer Leitfähigkeit und Stofftransport, PhD Thesis, Schriftenreihe angewandte Geologie, Karlsruhe, 179p.