Spray drift management has become a part of every farming operation but as the risk to crops increase, optimising the existing strategies and searching for new solutions is vital to minimising its effects, according to SA industry leaders.
Mid North-based consultant Peter Cousins, Crystal Brook, said growers needed to recognise they had a responsibility to hit their target and reduce spray drift.
He said there was an onus on growers to self-regulate when it comes to spraying, similar to to the protocol of the grassland fire danger index during harvest.
Mr Cousins, who is involved with Grain Producers SA’s Hit Your Target campaign, said increased droplet size was an important management tool to reduce spray drift.
He said increased water rates and the correct spray nozzles increased droplet size, while a low boom height position and reduced ground speed also cut drift.
“I really encourage growers to have someone else operate the system for a run. They can get out in the paddock and assess how the spray rig is operating,” he said.
“Critically assess what the spray pattern looks like, make sure the spray is hitting the ground and ensure that there is no drift behind the boom. If there is, make adjustments to reduce drift, recheck the weather and operating conditions and stop if necessary.”
If weather conditions permit spraying and drift is occurring, Mr Cousins says farmers need to make adjustments to the operating and rig system.
He said to first check the type of nozzles being used and whether the boom was spraying at the correct pressure.
“Also look at the boom height – best practice is to sit the boom 50 centimetres above the target,” he said.
“Operating speed is important so aim for 14 kilometres a hour to 22km/hr. But first, keep an eye on changing weather conditions and stop if in doubt, especially if at risk of an inversion.”
He encouraged growers re-educate themselves about spray drift practices, in particular temperature inversions and their effect on spray drift.
“Inversions occur on most nights 1.5 hours before sunset and up to 1.5 hours after sunrise, unless there is a continuing wind speed of over 11km/hr through the night or if it is overcast,” Mr Cousins said.
“Do not spray when there is no wind, there needs to be at least 3km/hr at all times. Growers can continue to spray up to 18km/hr,” he said.
“Monitor weather conditions in the paddock continually throughout the spray operation. Growers should check at least once every hour and are encouraged to use both a hand-held device and a reliable online weather forecasting service. These details should be recorded in a spray diary.”
Mallee graingrower and Bulla Burra operations manager Andrew Biele helps run a collaborative enterprise spread across 15,000 hectares on properties between Loxton and Alawoona.
Operating a cropping enterprise in a region with vineyards and almond and citrus orchards, Mr Biele has become conscious of the effect off-target chemicals could have on other industries.
But Mr Biele said reduced spray drift within Bulla Burra’s farmgate was just as crucial.
He said because 50 per cent of the cropping program was legumes and oilseeds, off-target issues within his own enterprise were not an option.
“We have got many different crop types within our own boundaries so we want to look after our own crops too,” Mr Biele said.
“But it is important agriculture, horticulture and viticulture work together. We are all producing food for the community and need to ensure this is produced to the highest standards,” he said.
Bulla Burra has implemented a number of measures to help eliminate the potential for spray drift.
“In the region, dawn and dusk are the highest risk times, particularly if it is very calm and warm. It is almost guaranteed there will be an inversion during these periods, so if these conditions arise we do not spray or if we are, we stop,” Mr Biele said.
“We continually monitor wind direction with a hand-held weather meter. We are looking for speeds above 3km/hr. We continually monitor weather patterns throughout the application period. It might take five days to finish spraying one paddock, but the team is dedicated to safety.”
Keeping detailed electronic and handwritten records of paddocks on an hourly basis is also a part of Mr Biele’s spray drift management plan, as well as using updated machinery and spray equipment.
Mr Biele said up-to-date nozzle technology was crucial.
“We use air induction nozzles for our summer spraying which have a very coarse droplet size so there is less chance of drift. We also use additives to reduce the spray fines,” he said.
Mr Biele said the recommendation of reduced ground speed while spraying had made a big impact on spray drift.
“We have reduced speed to ensure we get better droplet size management,” he said. “We just make sure we work within the pressure parameters of the nozzles.”
