Farmland on Sandy Creek Road in the Tully region now boasts a wetland as well as cattle and is acting as a water quality treatment system for the Great Barrier Reef lagoon.

Tully Sugar Limited set aside eight hectares of land to help trial ways of reducing nutrient and sediment run-off as part of a major reef water quality project.

The wetland has been formed on low-lying grazing land, using earthworks to encourage shallow flooding and allow natural wetland vegetation to grow back.

Since its construction in 2019, the wetland has been monitored for its effectiveness at removing nutrients and sediment from the water passing through. Data shows it is a high performing site.

As wetland vegetation has become more established, the wetland’s nitrogen removal capacity has consistently improved since construction. It is now estimated to remove over 1000 kg of nitrogen per year.

Tully Sugar Limited’s John Edwards said the company’s involvement in the project has been an opportunity to contribute to locally appropriate water quality solutions.

“It’s important to us that we’re not just talking about doing the right thing, but actually doing it.”

“The messages are clear. People want a productive and profitable sugar industry because it’s the lifeblood of our region, but they also want us to be environmentally sustainable.”

“Sugarcane is an important rural industry for the Wet Tropics, and Australia. We see it as our responsibility to take steps that ensure ongoing local and global support of the industry,” said Mr Edwards.

One of Australia’s largest sugar mills, Tully Sugar Limited exports locally produced, milled sugarcane to international markets.

The Wet Tropics Major Integrated Project’s Fiona George thanked the mill for their involvement.

In a world first, denitrifying bioreactors – woodchip filled trenches that intercept and treat nitrate in surface run-off and shallow ground water – now have comprehensive guidelines for their use in improving water quality leaving farms.

The Wet Tropics Major Integrated Project (WTMIP) has been a key player in agricultural bioreactor trials, with seven installed as proof-of-concept systems on cane and banana farms across the Tully and Johnstone basins.

The WTMIP’s place-based approach has modified conventional wall and bed bioreactor designs to trial three other designs (in-drain, ag pipe and partial in-drain bioreactors), developed with help from local growers and machinery operators to suit the unique nature of Wet Tropics landscapes.

WTMIP Catchment Repair Coordinator Chris Algar said the input received from participating landholders had been a crucial part of the process.

“They’ve not only provided us with sites to implement trials, but invaluable knowledge on the lay of their land.”

“The WTMIP is the first project to trial a range of different bioreactors, each designed to suit the landscape where they’re positioned.”

“There’s no ‘one size fits all’ solution. The variability of soil, land and water flow led us to tailor each bioreactor to the conditions,” Mr Algar said.

A denitrifying bioreactor works by intercepting surface run-off or shallow ground water. The carbon in the woodchip and low oxygen environment provides the right conditions for microbes to convert nitrate in the water into harmless nitrogen gas through the process of denitrification.

One advantage of bioreactors is the minimal impact they have on productive land.

“Bioreactors come in various shapes and sizes depending on their purpose.”

“The WTMIP trials required only a small area of land for construction, site selection was dependent on finding the right location in the landscape as not all locations were suitable for the trials.”

“The ideal condition for a bioreactor site is an area that’s freely draining, where leaching is occurring through the soil,” Mr Algar said.

The WTMIP bioreactor trials have enabled considerable research and understanding into how the water treatment systems work in Wet Tropics landscapes and conditions.

Carla Wegscheidl from the Department of Agriculture and Fisheries has managed the bioreactor guidelines project and said it was truly a collaborative effort.

“We couldn’t have completed these trials and research without the help of the Bioreactor Network, whose members include Jaragun EcoServices, Terrain NRM (the lead organisation delivering the WTMIP), James Cook University, Queensland University of Technology, Australian Wetlands Consulting and the Department of Environment and Science,” Ms Wegscheidl said.

The guidelines were developed as part of the Bioreactors for Great Barrier Reef and the Agricultural Water Treatment projects, with funding from the Queensland Government’s Reef Water Quality Program. These guidelines provide another tool for land managers looking for ways to reduce nitrate leaving Queensland farms.

Guidelines and fact sheets to assist with planning, design, installation and management of treatment systems in agriculture and aquaculture, to improve water quality can be found here.

Tully farmers – you’re invited to attend the Tully Sustainable Farming Day at the Showgrounds on March 17, from 8.30am – 1pm.

Hear about Tully farming progams, including Sugar Research Australia’s Cane to Creek Project and the Wet Tropics Major Integrated Project.

Get information on Paddock 2 Reef, the latest Wet Tropics Report Card and upcoming Terrain NRM projects.

Agribusiness displays from Liquaforce, Mirriwinni Lime, Farmacist, NuFarm, T.R.A.P. Services, Grower Support and more!

See short talks from Green Collar (Reef Credits), Cassowary Coast Regional Council (pig management), Tully Sugar (pre-harvest testing service).

Useful lucky door prizes up-for-grabs and morning tea and lunch will be provided.

RSVP is ESSENTIAL. Contact Maria Ribbeck from Tully Canegrowers on 0436 634 411 or maria_ribbeck@canegrowers.com.au

Event Program:

8.00am – 8.30am – Arrival, COVID-safe check-in to event

8.30am – 10am – Exhibitor presentations

10.10am – 10.40am – Morning Tea

10.40am – 11am- Welcome from Tully Canegrowers, Tully Sugar and Australian Banana Growers Council

11am – 12pm – Guest speaker presentations (Sugar Research Australia and the Wet Tropics Major Integrated Project)

12pm – 12.45pm BBQ Lunch

12.45 – 1.15pm – Lucky door raffle draw

1.30pm – 3.30pm – Where’s my N? workshop with David Hardwick from Soil Land Food.

This event is organised by the Wet Tropics Major Integrated Project, Tully Canegrowers, Tully Sugar Ltd, Sugar Research Australia and Australian Banana Growers’ Council.