Soil moisture measuring equipment

[Tim Calder]

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Calder, Tim writes:
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Hello Ken.
I have found that the accuracy of the equipment is not important in respect
of when to irrigate.  It is the repeatability of that piece of equipment to
give the same reading at the same soil moisture level. The slope of the
recorded data and balancing this against water use of the crop and
evaporation will define irrigation timing.  No equipment will nominate the
time to increase irrigation for events such as stone fruit sizing.  The
experience of the grower with the use of this equipment will increase
efficiency levels and maybe yields.  I have found that the ease of use of
the equipment is the important issue.  If the equipment is not easily
accessible the reading of the equipment tends to be  somewhat neglected.
For this reason we use a simple logger with probes connected to it at
salient points in the crop which is connected to a modem (12VDC).  It is
cheaper to use a radio but the distance we are from the various trial sites
demand the use of a phone connection. This is downloaded once a day to check
soil moisture levels. We have used TDR and tensiometers with pressure
transducers with out any problems.   Hope this may help.
Cheers Tim Calder.


> ----------
> From:
> owner-sowacs@aqua.ccwr.ac.za[SMTP:owner-sowacs@aqua.ccwr.ac.za]
> Sent:         Thursday, 14 March 2002 14:27
> Subject:      Soil moisture measuring equipment
>
> Ken Flower writes:
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> 
> We are about to purchase some equipment for measuring soil moisture.  This
> is for irrigation scheduling.  The options that I am considering are the
> Gopher (dielectric constant)and the Diviner 2000 (capacitance).
> 
> If possible, I would like an/some opinions on which is the most accurate,
> robust and cost effective of the options.
> ===8<===========
> 
> [Bruce comments
> Ken I have left your email address off so that all replies come back
> through this forum.
> 
> Anonymous comments will be posted, but preferably be bold enough to put
> your name under comments!
> Bruce]
> 
> 



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