Return-Path: postmaster@aqua.ccwr.ac.za
Date: Thu, 27 Nov 1997 07:28:27 +0200
From: Yossi Ingber 
Reply-To: netafim@inter.net.il
Organization: netafim@inter.net.il
To: owner-sowacs@aqua.ccwr.ac.za
Subject: Re: low cost production sensors : FLORI : NETAFIM?
References: <199711260608.GAA19322@aqua.ccwr.ac.za>

The FLORI is out in commercial marketing phase for the last 3 years,
 2 possible applications :
1) landscape - - - monitors a single electric valve by soil moisture
2) agriculture -- data collector to register soil moisture levels
Please send me your snail mail address , I will mail you the product
documentation.
Yossi  Ingber
Engineerring and Technical Support / Netafim Israel

owner-sowacs@aqua.ccwr.ac.za wrote:
> Harry wrote
> > I am interested in anyones experience with these or similar low cost
> > sensors of either the resistive or heat dissipation type in this type of
> > application where the sensors stay buried for long periods of time.
> >
> > I have been using this sensor since approximately 1985.
> >
> > Harry Whittle
> 
> [Bruce comments: anyone with more info on this "Flori from Netafim"  please
> send it on to sowacs.]
> 
> Harry,
> try the Flori from Netafim, it is a small capacitance probe made to
> schedule smallscale landscape irrigation. It is relatively new so there
> is not much information on the long time reliability.
> 
> Best regards
>  Jochen Eberhard

January 1, 1998
Dear Bruce:
Following my preliminary contact with you, I can see some benefit in
presenting past and current information regarding the Capacitance Soil
Moisture Sensor also known in some places as 'Flori' and distributed by
"Netafim" or its representatives.

History:
Since 1991, and for three intensive years, the Agricultural Research
Organization, (ARO), Ministry of Agriculture, State of Israel (through me),
and a small yet energetic engineering group (called Silora) have
cooperated to build and develop the above sensor.

FOR THOSE IN A HURRY I'LL MENTION RIGHT AWAY THAT A FULL
SCIENTIFIC REPORT  WAS PRESENTED IN THE AUS. J. OF SOIL RES.
1996, 34:361-368,
ENTITLED: "AN IMPROVED CAPACITANCE SENSOR FOR IN-SITU
MONITORING OF SOIL MOISTURE."

The idea was to build a cheap, accurate soil moisture sensor, for gardening
and agricultural applications, that will be free from texture and salinity
effects. 
In order to stay cheap we had to avoid the two classical solutions:
High frequencies (around 150 MHZ) or short time measurement (like, for
example in the TDR technology).
A combination of a little luck, and a lot of motivation, hard work, and
patience resulted in a prototype that satisfied our demands, under both lab
and field trials.
On 1994, due to financial disagreements we splitted.

Present Status:
Following changes introduced between the R&D and production phases
there was a negative progress with respect to the sensor's sensitivity.
The current version is disturbingly dependent on soil texture, salinity and
even temperature.
I speculate that this originated from the lack of a full understanding of the
principle of operation by the production team.
"Netafim" is fully aware of the situation and tries her best to overcome this
obstacles:
They hired people are cooperating with farmers dwelling in different
regions and soil textures. They supply the sensors and additional control
means (usually tensiometers) to better understand what has to be fixed.

Summary:
The presently (industrial) version of the Capacitance Sensor may
questionably have a single application option: A yes/no device for
controlling a valve in the garden;
Still, it will work empirically, relatively, extremely locally, and will still
dependent on temperature (which means that seasonal adjustments may
probably be necessary).

As for my efforts: After three years of additional work while looking for
funds (inside and outside the local administration), I temporarily gave up
until I get generous funds to enable the expensive next phases.
If the SOWAC subscribers have further questions, they can direct them to
me or you and I'll answer, if I can

sincerely, 
Arie Nadler
Dept of Soil Physical Chemistry
Soil and Water Inst, ARO
POB, 6 Bet Dagan Israel, 50250
E Mail: vwnad@volcani.agri.gov.i