proudly sponsored by
|
archiving of SOWACS proudly sponsored by |
|
"Peter Broomhall" <hortech@ats.com.au> writes
>We see again and again, both on this list and related lists
>(Irrigation/trickle) debate on accuracy etc of various soil moisture
>sensors. A lot of the time....
>>>>>>>>>>>>>>>>>>>>>
I appreciate Peter Broomhall's directness. Too often the focus does
seem to be on the sensor and not the interpretation of the data. Fact
remains, for
anybody to claim expertise in soil moisture feedback system design and
operation for irrigation schedulers, they'd better know the various
sensor's limitations
and sensitivity to spacial variation. What attributes establish the
value of a sensor?
Cost to deploy, obviously, and perhaps the following:
1) Return to field capacity reading (highest repeatability over time
and conditions on a scale of 1-10)
factored by the
2) Volume of soil considered ("sphere of interrogation" on a scale
of 1-10)
might yield an indicator
of "Dollars per unit of Reliability". The objective is to derive as
much reliable i.e. volume
information as possible for the least cost. After all, sensors aren't
the key. The sufficiently compensated experts to interprete the data
are the key.
The quest to manage water resources better, to return higher profits
to growers, while conserving water and fuel resources for future
generations, all the while minimizing irrigation pump-related air
pollution depends on expert interpretation of robustly constructed ,
expertly
installed sensors and data acquisition links. I wish there was more
sponsorship of
"demonstration" centers to show the comparativeness of different
sensors,
under differing deployment schemes. All the recent interest is great.
A recently
published quarterly newletter shows calculations and assumptions for
determining
number of sensors based on std. deviation and square root of mean..
It begs the question, Why aren't the sensors configured to sample a
larger
volume to start with?
Tom Reynolds
Water Balance
Mesa, AZ