The southern part of the Liverpool Plains is the only place in NSW, and one of the few in Australia, where sorghum can be grown in constant rotations – or as farmer Bernie Perkins says “sorghum on sorghum on sorghum”.

“We have fields near us that had 15 in a row – you can’t do that anywhere else,” he said.

About 15 local farmers – “but it’s probably more than that” – bought MR43 sorghum seed from Pacific Seeds (now know as Advanta Seeds). While there was nothing wrong with the sorghum, the bags were allegedly contaminated with shattercane, a weed that competes aggressively with sorghum and significantly reduces yield.

“The year we got it, the summer of 2011/12, we had these great big plants in our paddocks,” Mr Perkins said.

“We got rid of them, but the seeds are still there. That’s the problem, we can’t get rid of it, we can only manage it.”

The seeds can lay dormant for up to 12 years, however Mr Perkins is not convinced he’ll ever be able to eradicate the weed from the 160 hectares affected.

“There was an early episode on the plains, about 20 to 25 years ago with another company and those people are still fighting the shattercane,” he said.

He’s been forced to produce other crops that can grow with the shattercane, like “wheat, barley, even sunflowers”, which “may or may not be profitable”. Mr Perkins and the other farmers affected are taking part in a class action lawsuit against Advanta Seeds, seeking compensation for the damage caused.

“We’ve been forced to completely change the way we manage the farm, why should we change our management because they were slack?” he asked.

“We certainly aren’t making the money we were out of sorghum.

“Those crops definitely aren’t our first option. Sorghum on sorghum is the most profitable rotation for us and we can prove that.”

Instead of continuous sorghum rotations, Mr Perkins said he might be about to plant sorghum “one year in every three or four”.

In May, Advanta Seeds managing director Nick Gardner said the company could not comment as the matter was before the courts apart from to say it would “vigorously” defend all charges. The law firm behind the class action, Creevey Russell, will hold a shed talk in Willowtree at Graze on Wednesday, July 26.