The largest percentage of delegates was from government departments or quasi-autonomous non-government organisations and industry representatives.

In his opening address to delegates, Dan Galligan, CEO Queensland Farmers Federation, said the workshop was designed to reveal opportunities to farmers to enable them to apply restrictive mechanisms to control residue run-off from their properties.

Those farmers who did attend appeared to have gained some valuable knowledge from the workshop.

Wayne and Amanda Vickers, canegrowers from the Marian district, said they were impressed with the information delegates got from the field trip to the Hest and Risotto farms in the Claire region.

Mr Vickers said the diverse mix of experts provided by the government allowed farmers to get many different points of view on the situation.

"The information on the nutrient level in the run-off pits used in the trial will allow us to regulate our fertiliser application," Mr Vickers said.

He said the field trip also revealed to the farmers that many were overusing or incorrectly using herbicides.

"I spend up to $10,000 per year on the pre-emergent Velpar, and was told it would work better if applied during rain periods," he said.

"But at the field trial I was told that Velpar takes two days to bind with the soil, so by spraying in the rain I was probably losing a lot."

JCU professor Jon Brodie told delegates that the herbicides of most concern were atrazine, diuron, ametryn and hexazinone.

Professor Brodie said that during the wet season, it has been estimated that over one tonne of chemical enters the ocean in the Fitzroy district and hundreds of kilograms in the Burdekin Whitsundays.

He said that over the past three decades, there had been a steady increase in the use of chemicals and it is time that their use must be mitigated.