As
area producers struggle through though drought conditions, most seek to
maximize returns from limited irrigation capacity. Because our aquifer is not refilling nearly
as quickly as we are pumping, careful management practices to conserve water
are becoming even more pressing. Many
producers are making use of Low Energy Precision Application pivots, (LEPA) and
similar pivot systems to maximize their irrigation efficiency. When on the proper setting, these types of
systems use lower pressure regulated nozzles hanging fairly close to the ground
to limit evaporation waist and causes by limiting air exposure, crop overspray,
and heavily wetting a smaller area of soil surface. The
nozzles of a LEPA type pivot have three settings; bubble, spray, and chemigate. This allows the LEPA type systems some flexibility
and practicality in use.
When
irrigating a crop for a stand, most producers set their LEPA nozzles to spray
mode. This setting wets the entire soil seed
bed and better ensures a profitable stand of young seedlings that cannot search
very far through the soil for water on their own, but acts similarly to a
conventional sprinkler in water use efficiency.
An older style conventional
sprinkler system loses about 20 to 25% of the water pumped to wind and low
humidity while it irrigates in normal operating conditions. LEPA style systems only lose about 2 to 3% while
in bubble mode in similar situations. During very high and sustained winds,
something most area producers are all too familiar with, both systems do lose some
efficacy but the volume of water lost by conventional pivots is
staggering. In those situations, up to
94% of irrigation water applied can be lost.
The timing for producers to change the settings on their LEPA type
systems to bubble mode quickly becomes very important as we face water (and
money) loss issues. To maximize
irrigation efficiency, this switch to bubble needs to happen as early in the
growing season as possible.
Cotton,
our most pertinent area crop, first becomes capable of searching for its best
water source with its tap root system at match-head square stage. Cotton at younger stages benefits more from
the spray mode since it hasn’t developed the root system needed to take
advantage of the bubble setting yet. Producers
who make the change to bubble too soon often experience serious stand and or
yield reduction without the help of rainfall, which has been severely limited
lately. As cotton plants start getting
bigger, they start developing their fruit set and water use increases
drastically. Producers waiting too long
to change to bubble mode risk notable yield loss through fruit set, not to
mention the painful waist of precious water.
Our area’s
cotton fields are ranging from 1st true leaf to pinhead square stage. For several fields, match head stage is only
a few days away. For this reason we urge
producers and consultants to keep close tabs on the stage of their cotton
fields.
Have a GREAT
day, Please
call or come by if we can help,
Kate Blayne
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