Reducing fertiliser use on cane farms in North Queensland

Ingham cane grower Robert Bonassi has focused on fallow crops and using mill by-products to slash his fertiliser rates without affecting yield.

Mr Bonassi cut his fertiliser rates by up to 20 per cent over four years - moving from 160kg of nitrogen per hectare to 120-130kg for plant cane and 145kg for ratoons.

He said maintaining healthy soils was essential.

"We'd always taken soil samples but now we target every block we fallow on a yearly basis," Mr Bonassi said.

"You've got to keep the soil healthy when you're reducing nitrogen and phosphorous."

The Bonassi family grows cane on 180ha over four parcels of land, with 25ha under fallow crops at any given time. They moved to mounded rows and zonal tillage to solve waterlogging issues, manufactured a zonal ripper and mounder, and bought a bean planter last year.

They are also sold on mill mud and mill ash for its nutrient and soil conditioner properties.

"We apply sub-surface mill mud and ash in the fallows. Slowly, it is building our soils up and helping us with reducing our fertilisers," Mr Bonassi said.

"We spread zonally at the end of every year, using about 80 tonnes to a hectare.

"Within five years we'll have gone across the whole farm with 80 to 100 tonnes per hectare of mud and ash and we should start seeing results. Then we'll look at halving that and see if we can still meet the nitrogen levels."

His farm is 6km from the ocean as the crow flies. Two of the parcels of land have three creeks running through them and one shares a boundary with national park.

"It's all about getting a good balance - good returns on the soil while minimising run-off to the very best of our ability,'' he said.

Mr Bonassi is one of 39 growers to take advantage of the Australian government's Reef Trust IV program, delivered through the Wet Tropics Sugar Industry Partnership.