HOW much an average competent mushroom picker can pick is the subject of hot contention during an underpayment case.
The National Farmers' Federation become an intervenor in the Federal Court case brought by the Fair Work Ombudsman against Marland Mushrooms, it's owner Troy Marland and labour hire firm HRS Country.
The Staplyton farming business has been accused of underpaying more than 400 workers $646,000 during an eight-month period in 2014.
The case may have wider implications for piece rates, which are widely used throughout agriculture.
Under the Horticulture Award, if piece rates are paid to pickers it must allow an "average competent worker” to earn at least 15 per cent more than the minimum hourly rate.
Barrister for the NFF Richard Dalton previously described the FWO's case as "fundamentally defective”.
During the Federal Court hearing he explained to justice Darryl Rangiah the importance of piece rates, as horticulture involved seasonal work and the need to harvest produce quickly within short periods of time; essentially, piece rates encouraged reliable employees to work hard and be rewarded for their effectiveness during that time.
Mr Dalton urged Mr Rangiah to view the FWO's pick-rate data highlighted during the trial "cautiously”, as much of the information presented was taken after the underpayment investigation.
FWO barrister Justin Bourke argued that during an eight-month period in 2014 the average number of kilos picked per hour was 14, short of the 29.5 kilos needed to reach the award.
He argued there were hundreds of workers employed by HRS Country and "not one” was able to meet the average needed.
However, counsel for Troy Marland, Robert Bain, argued competent mushroom pickers could collect more than 30 kilos per hour, "and they could do it comfortably”.
He also said top pickers, "the Jackie Howes of mushrooms” could pick up to 80kg per hour.
He suggested there were three attributes of an efficient mushroom picker: diligence, aptitude and experience.
But he said not all employees had the desire to obtain those qualities.
Mr Bain stressed the pick-rate data was collected during a time when workers were heavily transient, some not staying longer than a few weeks, so the experience needed to reach the average was not obtained.
He said it was "common sense” that workers would pick faster the more experienced they were.
However, in Mr Bourke's closing arguments he said there were workers receiving as little as $5 per hour, "so it's no wonder why they left”.
He said a rate needed to be set for an average competent employee within that working environment.
"It's... not bust a gut and work like you are in a sweat shop so you can make the rate,” he said.
The matter has now been adjourned.