�From:�	Bruce Metelerkamp (BRUCE)
�To:�		SOWACS@aqua.ccwr.ac.za
�Date:�	Monday, May 20, 1996  9:44 am
�Subject:�	tensiometers - hysteresis & range

PIZARRO HUMBERTO wrote:

>Dear Mr Meterlerkamp:
    
>I need to carry out an experiment to measure soil moisture 
> tension VS moisture content in undisturbed soil column to
> identify hysteresis. Could you indicate to me where I can get
> tensiometers to measure the soil moisture tension in the range
> from close to saturation to close to dry?.

Tensiometers are capable only of measuring in the "wet" range -
say anything from 0 down to 80 kPa. (Dry to me is 1500 kPa!)
If this an adequate range for your requirements, than I am sure
there will be many suppliers out there who will respond to your
plea. (For example, Irrometer for one has model that works to a
high tension).

Mini-tensiometers may be required for this application due to the
limits in size. (As a student I made up some of these quite
sucessfully from mini-cups and Swagelok tubing and connectors to
a mercury column).


If 80 kPa is not dry enough, you will have to use another type of
sensor - psychrometers perhaps?

See the directory listings of supply companys on both my SoWaCS
page, and Richard Mead's MIF page:

http://www.icfrnet.unp.ac.za/~metele/sensorlinks.html

SUPPLIERS TAKE NOTE - I AM LOOKING TO EXTEND THE DATABASE OF
SUPPLY COMPANIES ON THIS PAGE - PLEASE SEND ME YOUR DETAILS.
(SOIL WATER SENSOR -RELATED ONLY PLEASE)

Richard Mead's ddd
http://www.cybergate.com/~rmead/ddd.html

-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.
Bruce Metelerkamp           SOIL WATER RESEARCH OFFICER
Institute for Commercial Forestry Research,
University of Natal, PO Box 100281
Scottsville, ZA3209
Rep. of South Africa             Voice:27 331 62314
E-mail: bruce@icfr.unp.ac.za       FAX:27 331 68905
URL http://www.icfrnet.unp.ac.za/~metele
                                        /SoWaCS.html
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Host of SoWaCS (Soil Water Content Sensor) Discussion List.