Re: Information on Aquaterr 200 Soil Moisture Meter

[Blaine Hanson]

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I have used the Aquaterr meter and have tried to develop calibration curves
between instrument reading and soil moisture content. The instrument is a
capacitance device. It provides a qualitative reading that, based on my
calibration efforts,  does respond in many cases to changes in soil
moisture content. However, at one sampling location, the instrument did not
respond to changes in soil moisture content. The calibration cuves, which
were developed by taking a small soil sample next to the instrument
sampling point and then measuring the volumetric soil moisture content of
the soil sample, showed  a lot of variability, with coefficients of
determation as low as 0.44.  I feel that this variability may limit the
instrument's ability to detect relatively small changes in soil moisture
content.

The Aquaterr meter is designed to be move for location to location.  My
experience has been that taking numerous instrument readings at a given
time for a given locationcan result in considerable variability in the data
possibly due to soil spatial variability, but perhaps also to instrument
operation.  Dielectric instruments require a tight fit between electrodes
and soil. However, as one pushes the Aquaterr into the ground, it is nearly
impossible not to slightly wiggle the instrument as it is pushed , which
tends to create a slight gap between instrument and soil.  

At 10:31 AM 8/23/99 +0000, you wrote:
>NOTE:  To get off this list, send email to majordomo@aqua.ccwr.ac.za
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>
>
>One of my clients recently brought to my attention a soil moisture
>measurement device sold by Spectrum Technologies called the Aquaterr 200
>Soil Moisture Meter.  He was interested in it for use in raingrown cropping
>as a means of determining stored soil moisture which is an important issue
>when making planting decisions here in Central Queensland.  Is anyone
>familiar with this device?  I have several questions about it:
>* How is it meant to work?
>* How accurate is it?
>* How robust is it for use in the manner suggested?
>
>There is only limited information at the Spectrum Web Site (at
>http://www.specmeters.com) on this device. 
>
>Regards,
>Graham Harris CPAg
>Find the Aussie-Nets at: <http://lists.dpi.qld.gov.au/> 
>******************************************
>Senior Extension Agronomist
>Farming Systems Institute
>Dept of Primary Industries
>LMB 1, Biloela, Qld, 4715
>Phone: 061 7 4992 9103
>Fax: 61 7 4992 3468
>Mobile: 0419 728593
>E-mail: harrisg@dpi.qld.gov.au
>Listowner: Aussie-FieldCrops-Net
>Listowner: REC-AdultLearning-L
>President, Central Qld Branch AIAST
>******************************************
>
>
>[Bruce comments:
>>From a brief search, I also came up with very little useful information.
>However, in the sowacs archives there is one occurence of "Aquaterr" - in
>1996, and it, too is a request for more information on this sensor:
>www.sowacs.com/archives/arch.9612/msg00028.html (attached below)
>Perhaps from this post, some useful info has come to light that could be
>shared through sowacs?
>
>(Please note that I am currently updating all the archives into an indexed
>easy to use format, but navigation of the archives is not yet complete).
>
>
>Richard Mead has another photo of this on his website:
>http://www.microirrigationforum.com/new/sensors/aqpr.html
>ends]
>
>==========================
>FROM THE SOWACS ARCHIVES:
>
>`Aquaterr' soil moisture probes
>
>     To: sowacs@aqua.ccwr.ac.za 
>     Subject: `Aquaterr' soil moisture probes 
>     From: Graeme D Buchan <BUCHAN@tui.lincoln.ac.nz> 
>     Date: Mon, 23 Dec 1996 11:06:47 +1300 
>     Organization: Lincoln University 
>     Priority: normal 
>     Sender: owner-sowacs@aqua.ccwr.ac.za 
>
>
>Greetings to all soil hydroscholars.
>
>I seek information on the `Aquaterr' range of soil moisture probes
>(spike-type probes, which are pushed into the soil for quick spot 
>readings, and apparently based on a capacitance principle).
>
>* First, I wish to contact the US supplier, and would appreciate a 
>contact address (preferably email).   I have tried to contact this 
>firm using outdated brochures, but without success.
>* Second, I would be grateful for comments on the utility of these 
>probes, specifically for use in turfgrass or tree irrigation (i.e. 
>municipal and recreational use, rather than in research). 
>Thankyou,
>
>Graeme Buchan, NZ
>
>
>Dr Graeme D Buchan,  
>Reader in Environmental Physics & Environmental Education,
>Dept. of Soil Science, PO Box 84, Lincoln University, 
>Canterbury, New Zealand
>

Blaine Hanson
Irrigation and Drainage Specialist
Department of Land, Air, and Water Resources
University of California, Davis
Davis, CA 95616
Tel: 530.752.1130
FAX: 530.752.5262