Aerial application


There are many ways to apply both liquid and dry granules from the air, however only a very limited number of mechanisms that are capable of aerial precision. Furthermore the correct equipment still presents a myriad of factors that have to be controlled to increase the precision outcome.

Granular Products will only allow our accredited aircraft to use either a Meterrate® or an Isolair® type of equipment for fixed winged aircraft and helicopters. These mechanisms have been specifically designed for low rate, precision application and not designed for fertiliser application or fire-bombing.

After installation these mechanisms need to be “Pattern Tested” for every different product that is to be applied. Different products have different spread dynamics and swath widths. “Pattern Testing” identifies what an effective swath width is and whether there is an uneven distribution across the swath, the testing then allows the operators to adjust their set-ups to correct any issues.

SprayCheck P/L, Australia’s only Pattern Testing Company, has seen and corrected a range of aircraft. Some liquid applicators had Co-efficients of Variation (CoE) of up to 65% (a variation of 32.5% (nearly a third) above and below the prescirbed application at the target) and granules with a CoE of up to 45%. Granular products will only accredit aircraft with a CoE of less than 10% (maximum of 5% above and below).

The advantages of granules over liquids for aerial application and spread dynamics are considerable. SprayCheck has stated that a well set-up liquid application will still have a CoE of 20%, which is due to small droplet drift, evaporation and wind issues, all of which do not affect granules.

Granules with a high bulk density allow for high coverage at low weight applications, while liquids need large quantities of water to achieve a similar coverage. If low water rates are used then coverage will be compromised and actives like Flupropanate will be unable to efficiently get to the soil. Gravity ensures that the granules deliver the active to the soil and target, while liquids will be caught within the biomass and canopy and most probably dry, until the next rain event.

List of Acredited Applicators