�From:�	Peter Waldispuehl ("peter.waldispuehl")
�To:�		sowacs@aqua.ccwr.ac.za
�Date:�	Monday, July 29, 1996  4:10 pm
�Subject:�	monitoring - field experience

Hello,

I'm employed for a project called "Longterm Forest EcosystemResearch"
(LTFER) and I have joined SoWaCS a few days ago. I am responsiblefor soil
physics and soil water studies on the Swiss LTFER-plots. Thisincludes
water balance quantification, determination of soil hydraulicproperties
and water balance modelling.
Because I have no field experience, I'm very interested inexchanging
information with scientists doing field monitoring.

I started my work a few weeks ago. My first goal now is thedetermination
of the (field) water characteristic function for some of theplots.

1) What kind of instruments (with respect to accuracy, samplevolume,
resolution, ...) might be advisable for this kind of task.
2) Topp and Davis (1985) describe a vertical installation of TDRrods to
get less disturbance than with horizontal measurements (no pitnecessary).
Does this work with rods of about 1 m length in any soil?Experiences with
this kind of installation?
3) Alpine plots pose a special problem: installation andmeasurements are
disturbed by a very high stone content. Any solutions? Is therefor example
a possibility to correct TDR-readings for stone content? Whatabout other
kind of soil moisture sensors?
4) What are the experiences with FDR sensors so far?
5) Recommendable literature on the determination of field water
characteristic function?

Thanks for any hints!




Literature: Topp, G. C. and J. L. Davis. 1985. Measurement of soilwater
content using time-domain reflectometry (TDR): a field evaluation.Soil
Sci. Soc. Am. J. 49:19-24

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Peter Waldispuehl
Soil Physics (Long-term Forest Ecosystem Research)
Swiss Federal Institute for Forest, Snow and Landscape Research
Zuercherstr. 111, CH-8903 Birmensdorf ZH, Switzerland
e-mail  peter.waldispuehl@wsl.ch
Phone   ++41 1 739 25 92           Fax     ++41 1 739 22 15
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