MACADAMIAS - THE SMALL GROWER - A SIMPLE SPRAY RIG WITHOUT AIR ASSISTANCE.

MACADAMIAS - THE SMALL GROWER - A SIMPLE SPRAY RIG WITHOUT AIR ASSISTANCE.

This is the initial "trial and error" to see if it's possible to get effective canopy penetration without air assitance using various air induction nozzles-tips

THE TREES

Macadamia var. Beaumont. Height 5 to 6 metres. Inter-row spacing 5.5 metres and intra-row plantings at 3 metres. Trees per hectare = 624. Trees pruned.

VERTICAL BOOM

Here's a pic showing the vertical boom set-up.

Nozzle espacement = 50 cm. Note the pressure guage (0 - 4000 kPa) at the bottom of the boom.

THE PUMP. A positive displacement pump with a maximum output of 30 litres per minute was used. This flow rate obviously limits the size of the tips used.

COVERAGE - The only way to monitor coverage is to use water sensitive paper to see if the droplets reach the target.

Two 5 metre aluminium tubes with water sensitive paper placed at 1 metre intervals were placed close to the tree centres.

THE NOZZLES - AIR INDUCTION TIPS

Two types were tested. The eight AITX air induction hollowcone tips used allowed a maximum pressure of 15 bar which was actually ideal. OR SO I THOUGHT.The problem was that canopy penetration was poor to non-existent as evidenced by the use of water sensitive paper.

The second type was the AI air induction flat-fan tip. The 7 tips used allowed only a maximum 7 bar (700 kPa) pressure. Here's a pic of the AIC tip mounted on a split eyelet.

Here are the pics of water sensitive paper from the bottom up. The first cards were placed 1 metre above ground level.

NOTES

Variation in droplet distribution is to be expected depending on canopy density and branch and foliage obstruction. Good penetration was achieved.

Vehicle speed = 4.5 km/ hr. A similar rig would be mounted behind a tractor. Slower speeds and better placement of the vertical boom would help.

Spraying on a slope and clearance between the rows is always going to be a problem.

Smaller nozzles in the AI, AIXR and AIC range need further testing. Second "trial and error" coming up.

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