Measuring Soil Water Potential Near A Wetland

[tsn...@dudek.com]

We are interested in purchasing soil water potential sensors to
measure the soil water potential at 1 and 3 feet below land surface
(BLS). The scope of the project is to determine the source of water
supporting a wetland. Two sensors will be installed at two
locations. We need to accurately determine the difference in soil
water potential vertically. Since the study area is located near a
wetland we are expecting very low soil water potential readings (0-20
cbars). Therefore, we need a sensor that is accurate, easy to install
and moderately priced. Any suggestions?

Thanks,

Torin

[Jochen Eberhard]

Torin,

check out the special tensiometers for nurseries and greenhouse
applications. They are made out of very porous material in order to work
very fast at the wet end.

Best regards,

Jochen

Jochen Eberhard, Dipl.-Ing.agr. (Hohenheim), Dr.Agr.(TUM)

Irrigation Researcher/Agronomist

NCEA (National Centre for Engineering in Agriculture)

University of Southern Queensland

West Street

Toowoomba 4350

Australia

Tel: +61 (0)7 4631 1989

mobile: +61 (0)428 765 372

Fax: +61 (0)7 4631 1870

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[Ali]

 

Hi guys,

 

any one who knows where I can buy a flow meter module from?

I am designing a system and need a flow meter that ouputs raw reading -

analog or digital output that I can interface to another circuit. (not self contained).

 

best,

Ali

[dbar...@ecs.umass.edu]

I haven't gone to any of these sites, but a quick www.google.com search came up with these:

http://www.google.com/search?hl=en&q=%22flow+meter%22+water+digital+analog&btnG=Google+Search

Flow Meter Superstore
www.Instrumart.com/Flowmeters A Flow Meter for Every Application. Talk to an engineer or shop online.

Ultrasonic Flowmeters
www.instrumentsdirect.com Top Quality Ultrasonic Flowmeters Buy Or Rent At Great Prices

Digital Flow meters
www.sotera.com For corrosive and non-corrosive fluids. Buy online - free shipping

Digital flow meters - all the Manufacturers | Industry ...

It is brand new micro-electronic flow meter in the water industry. ... Digital or analog mass flow meters, regardless of manufacturer, serve a single ... www.directindustry.com/industrial-manufacturer/digital-flowmeter-65510.html - 67k - Cached - Similar pages

Bronkhorst USA LIQUID mass flow meter & controller technology on ...

With analog and digital output. Laboratory style housing and with elastomer sealed construction. Flow ranges from 0-5 g/h up to 0-1 kg/h water-equivalent. ... www.bronkhorstusa.com/en/products/liquid_flow_meters__controllers/ - 25k - Cached - Similar pages

Flow Meters - Flow Meter Distributors - Flow Meter Manufacturers

John C. Ernst provides flow meters?digital and mechanical plus vane and piston?which are used as water flow meters (plus for other liquids), gas flow meters ... www.iqsdirectory.com/flow-meters/ - 43k - Cached - Similar pages

Flow meter and flowmeter manufacturers of peak, air, water, and ...

Flow meter distributors. Flow meter manufacturers. Flow meter suppliers. ... 14-gas calibrations per unit, digital and analog communication, 100:1 turndown. ... www.flow-meters.biz/ - 37k - Cached - Similar pages

sanitary flow meter water flowmeters

>>Flow meter Companies Advertise with us! your company can be here, Click here<< .... MeterCenter is a national distributor of both analog and digital panel ...
www.flowmeterdirectory.com/flowmeter_companies.html - 64k - Cached - Similar pages

[James Kennedy]

I would suggest a watermark sensor and a Hobo logger.

Eienaar Kennedy Besproeiing
Posbus 30309
Pellissier
9322
Bloemfontein
South Africa
Email: ja...@kbk.co.za
Website : www.kbk.co.za, www.ech2o.co.za, www.data4u.co.za
Tel: +27-51-4225767
Fax: +27-51-4225766
Sel :(+27) 0839627305
Skype VoIp : jameskennedybloemfontein

[James Kennedy]

Ali,

I would suggest McCrometers's, McPropeller,

JAmes

Eienaar Kennedy Besproeiing

[Jochen Eberhard]

I thought watermark sensors wouldn't be very accurate between 0 and
10kPa?

Best regards,

Jochen

> -----Original Message-----
> From: sow...@googlegroups.com [mailto:sow...@googlegroups.com] On
Behalf

This email (including any attached files) is confidential and is for the

[Skewes, Mark (PIRSA)]

I agree with the comment about sensitivity of Watermark Sensors at low tension (0-10kPa).

Here in South Australia we have monitored drainage using paired tensiometers, we have used T4 and T8 tensiometers from UMS in Germany. These are both loggable, refillable tensiometers, the T8's will tell you when they need refilling.

We log the tensiometers using systems developed here in SA by a local electronics company, Measurement Engineering Australia, but I am sure that UMS would have their own logging products. Cost is not dirt cheap, T4's are cheaper than T8's.

Hope this helps,

Mark Skewes
Research Scientist (Water Resources and Irrigated Crops)
South Australian Research and Development Institute
Loxton Research Centre, Bookpurnong Road, Loxton
PO Box 411, Loxton SA 5333
DX 52102
T: 61+8+8595 9149 F: 61+8+8595 9199 M: 0408 800 681
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[Oscar Cainelli]

I agree completely with Mark Skewes, we are actually using in laboratory the
mini tensiometers T5 from UMS and they are very accurate (+- 0.2Kpa) and
quick responding. I guess that T4 and T8 hold similar characteristics.

The price for the T5 is roughly 400 euros each (I recently ordered a couple
more of them). I don't know about the price of the T4 and T8 but I guess
they should be lower than that of T5.

Good luck

PhD ing. Oscar Cainelli
Civil & Environmental Dept.
University of Trento
Via Mesiano 77
38050 Povo di Trento (TN)
Italy
tel. +390461882637

[Rodney Thompson]

For soil matric potential measurement in the 0 to -10 kPa, the Watermark is not at its best.  We evaluated the performance of the Watermark with different  calibration equations, and once in the  0 to -10 kPa range, the Watermark becomes unresponsive, with the maximum value for a given soil being determined by the calibration equation used (see Thompson et al 2006, Evaluation of the watermark sensor for use with drip irrigated vegetable crops. Irrigation Science, 24, 185-202).

We used tensiometers from Skye Instruments (Model SKT 600/IE) to measure in this range.  They appreciably cheaper than the price mentioned for the T5; however, they require an in-house logger which appreciably increases the price of the overall package.  Also, their working range is 0 to -80 kPa, so they may not have best resolution for the small range of interest here. 

Something that may be of interest is the Irrometer MLT-RSU small tensiometer.  It has 4-20 mA output and is offered  with two calibrations of 0 to -16 and 0 to -32 kPa.  I think they are about half of the price mentioned for the T5.  A colleague used them in perlite in a greenhouse and seemed reasonably happy with them. I don't have any information on how they perform in soil under field conditions.

Rod Thompson
University of Almeria,
Spain

ROD THOMPSON
Universidad de Almería,
Dpto. Producción Vegetal,
Edificio CITE-2B,
La Cañada
04120 ALMERÍA
SPAIN

Tel: ++34 638140123
Fax: ++34 950 015939
E-mail: rod...@ual.es

[Lauren Bissey]

The UMS tensiometers can be logged by Campbell Scientific data loggers.

Lauren Bissey

Hope this helps,

Best regards,

Jochen

<

---------- Original Message ----------

FROM: "Skewes, Mark \(PIRSA\)" <Skewe...@saugov.sa.gov.au>
TO: <sow...@googlegroups.com>
DATE: Thu, 6 Sep 2007 14:39:10 +0930

SUBJECT: RE: Measuring Soil Water Potential Near A Wetland

Hope this helps,

Best regards,

Jochen

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