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SECTION 7
SPRAYING INFORMATION
b) Set the sprayer operating and record the time taken to
travel 100 metres at your required spraying speed.
c) Calculate the actual speed of travel using the formula:
For SPEED, km/hr =
using the following formula:
Distance (m) x 3.6
Time (sec)
eg. 100(m) x 3.6 ÷ 48(seconds)
= 7.5km/hr travel speed
An alternative formula is:
km/hr = Metres travelled in 1 minute
STEP 3 - DETERMINE SPRAYING
VOLUME REQUIRED
It is essential to determine the liquid volume per hectare
required to effectively spray a crop without overspraying
or underspraying.
The spray volume requirement should be determined by
/ in conjunction with an agronomist / spray manager /
someone skilled in the art of spraying.
The term “litres per hectare” must be related to foliage
and not just to land area. The amount of liquid needed to
effectively spray any given crop will vary greatly with:
• The type of crop
• Row spacing
• Width of canopy
• Height of canopy
• Stage of growth
• Density of foliage
• Type of leaf surface
• Type of fruit (single or bunched)
• Type of sprayer used
STEP 4 - DETERMINE SPRAYER
CONFIGURATION
Once the volume of required spray volume per hectare
is established, the next step in setting up the sprayer is to
determine:
• The
number of row(s)
to be sprayed in one pass, and
• The
total number of nozzles
to be used on the
sprayer.
Both these factors can vary with the model of sprayer used
and other factors mentioned under step 3.
Example A
The HL600/800 model uses 7 rollover nozzles per side
for a total of 14 nozzles. In some applications several of
these nozzles might be turned off.
In other applications several of these nozzles might be
fitted with a larger orifice in order to target a specific
section of the canopy.
STEP 5 - DETERMINE THE IDEAL
SPRAY PRESSURE
Before determining the correct nozzles, it’s best to have an
idea of the spray pressure required. As a general rule, a
pressure of 10 to 15 bar is considered ideal. Setting up the
sprayer around a pressure of say 12 bar will allow lower
pressures (say 10 to 12 bar) to be used in early season
and higher presssure (say 12 to 15 bar) for later season
without having to change nozzles midseason. It will also
offer some margin around travelling slower or faster than
the chosen speed.
The advice provided above is general information only
and operators should seek specialised advice from their
agronomist/spray manager/someone skilled in the art
of spraying.
STEP 6 - DETERMINE & SELECT
CORRECT NOZZLES
Knowing actual travel speed, application rate required,
number of rows to be sprayed in one pass, total number
of nozzles to be used and ideal spray pressure, we can
determine the nozzles required for the sprayer.
The calculation formulation is;
Litres/Minute/Nozzle
(Litres per minute per nozzle)
= Litres/Ha x Km/hr ÷ 600
total number of nozzles used
x row spacing (m)
x number of rows in one pass
Summary of Contents for CROPAIR 300
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