Hawke's Bay fertiliser and lime company Hatuma is being praised for making a priority of safety.
The company's trials test the jettison capability of the fertiliser and require the pilots to release the load of fertiliser immediately after take-off.
Industry standard requires that a top-dressing pilot should be able to dump 80 per cent of the load within five seconds.
Hatuma marketing manager Aaron Topp says that in such a high-risk activity it is important that pilots can release their load quickly if they run into trouble.
"Pilot safety is paramount and, while we have successfully worked alongside the top-dressing industry for 50 years, there has been a recent move by farmers to further improve fertiliser efficiency and safety," he says.
"We want to ensure our dicalcic phosphate is the best quality so it flows well out of the plane's hopper."
Pilots are welcoming the trials. Hawke's Bay pilot Josh Calder does about 100 take-offs and landings each day and feels safe when using Hatuma's dicalcic phosphate because it releases well from the hopper.
"A pilot's safety should always come first," he says. "The fertiliser has to flow properly and, if it doesn't, we put our lives at risk.
"I have sent other fertiliser back in the past because it was poor quality and unsafe to spread. I wasn't prepared to take any risks.
"We rely on the fertiliser companies to get it right. It needs to jettison well so we feel safe.
"You are never going to alleviate all risks when you are a top-dressing pilot, but if we can minimise it, we can feel assured."
He praises the company for making a priority of safety. "It's the first time a fertiliser company has worked with us to ensure we feel safe while using its product," Calder says.
Oamaru pilot Greg Bayliss welcomed the safety testing and hopes more fertiliser companies will follow suit. "I have been a top-dressing pilot for 30 years and I have been in some dangerous situations. If you can't get rid of your load fast enough you could be in serious trouble."
He says farmers also carry some responsibility, which is to ensure the product is stored properly and remains dry.
Hawke's Bay farmer and aviation enthusiast Gary Peddle buys 300 tonnes of Hatuma dicalcic phosphate each year to spread on his farm.
He has a large fertiliser bin and says it's important to store the products well.
"The cost of fertiliser is huge for a farmer," he says.
"I spend about $70,000 each year on fertiliser so I don't want to jeopardise the quality of the product and compromise pilot safety."