Soil knowledge key to protecting Great Barrier Reef

THE more farmers know about their soil, the more the reef can be protected.

That is one message from a soil expert who has spoken about how dirt impacts the Great Barrier Reef.

CSIRO research director and soil expert Mike Grundy said the flow of nitrogen and sediments from land into the ocean and onto the reef was not a reason to stop agricultural production.

"The answer is to have efficient production," he said.

Mr Grundy, who was the guest speaker at a Rural Press Club function to celebrate the Year of Soils on Thursday, said soil was essentially the root of problems facing the Great Barrier Reef.

"And the issue is how much nutrients, pesticides and sediment do we get on the reef."

He said nitrogen and sediment moved through the ground and this movement was dependent on gullies and streams.

"You end up with a complicated set of things," he explained.

"The way in which the science part is dealing with it, is through a combination of measurement and modelling.

"You can't measure everywhere so you have to model in between."

He said modelling showed the nutrient efficiency where sugar cane and bananas were grown and indicated whether or not there was excess nitrogen.

But he said having better technology and knowledge about soil would be more beneficial than modelling.

"The Rolls-Royce is you end up with farmers that are using technology, that know enough about their system and they can adjust their inputs that only very elite farmers are able to do at the moment.

"If you're able to run a system like that, it is in your interest and it is in the reef's interest."

He said it was time soil knowledge moved beyond "trial and error".