A boggy spot on a Mourilyan cane farm has been converted into a high-performing “constructed” wetland, removing more than 90 per cent of nitrate from water in the system. 

The Wet Tropics Major Integrated Project team has worked closely with wetlands experts and a third-generation cane farmer to transform the low-lying and unusable strip of land into a water treatment system on his 101-hectare property. 

The 1.2 hectare wetland is proving that, with some remediation and construction, low-lying wet areas can effectively remove high levels of dissolved inorganic nitrogen from the water. 

Acting Project Manager Fiona George said this wetland shows the potential of wet areas on farms to improve the quality of farm run-off water. 

“This constructed wetland is evidence that a wet piece of marginally productive land can yield excellent water quality outcomes with the help of a tailored design and relatively minimal earthworks,” Ms George said. 

“We enhanced existing features that helped it to perform as a denitrifying wetland.” 

Vegetation uptake has been a key factor, with a thriving ecosystem of plant life establishing itself in a short timeframe and enabling the denitrification process to occur. 

The Wet Tropics Major Integrated Project has trialled a range of catchment repair systems in the Tully-Innisfail area, including seven different bioreactor designs, a landscape wetland, three in-drain wetlands, a high-efficiency sediment basin, three constructed wetlands and a riparian revegetation site. 

The constructed wetlands are yielding the best results, proving that, with improved hydrology and the appropriate amount of vegetation, they have high potential to reduce nitrate levels.  

Queensland Environment Minister Meaghan Scanlon has committed $3 million in funding for local-scale water quality monitoring in the Tully and Johnstone catchments.

This funding is to continue the water quality monitoring undertaken over the last four years as part of the Wet Tropics Major Integrated Project. The project has achieved unprecedented buy-in from the local community on water quality issues through bringing together Tully and Innisfail Canegrowers and the Australian Banana Growers, farmers, scientists, industry experts and Traditional Owners.

The grassroots, farmer-led monitoring program is answering growers’ questions about water quality by directly sharing locally relevant, nutrient, sediment and pesticide data from local catchments.

“Growers value and appreciate high quality local data that’s provided within useful timeframes. The local-scale monitoring of streams, paddock run-off and ground water enables us to build understanding about pollutant loss pathways and helps growers make informed paddock management decisions,” said MIP Water Quality Project Leader, Alicia Buckle.

Grower Services Manager from Canegrowers Innisfail, Deb Telford, said: “The Local Scale Monitoring program had such an impact in our district. To stop the momentum of this project would have been disappointing. This announcement today is exciting and is a positive step forward for the next three years. Grower engagement for this project has been encouraging and successful, we’ve had growers say we should have had this 10 years ago.”

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.

Over twenty-five banana growers gathered in South Johnstone recently to learn more about one of their most important assets – soil.

The Australian Banana Growers’ Council workshop gave growers a taster into the five principles of soil health, the qualities and benefits of healthy soils and steps to success.

Wet Tropics Major Integrated Project (WTMIP) Tully Basin Coordinator, Fiona George, presented at the workshop and works closely with growers to help improve their soil health.

“Getting the fundamentals right in farming is crucial for optimal productivity.”

“Managing factors that limit fertility and plant production requires not just the use of fertilisers and soil amendments, but more importantly the use of good management practices in the right sequence.”

“A significant benefit of improved soil health is more efficient nutrient use and increased pest and disease suppression which can also lead to reducing fertiliser and other chemicals running into waterways – this is something that the WTMIP is working closely with growers and industry to help improve,” Ms George said.

Australian Banana Growers’ Council Best Management Practice Manager, Amelia Foster, said it has been some time since the organisation has run a soil health workshop for growers in the area.

“We’re happy to run more soil health related workshops for banana growers as it’s a topic of interest for most growers.”

“Terrain is running a six-day program of soil health training, called Digging Deeper between November 2020 and April 2021. Banana growers with an interest in soil health on their own farm are strongly encouraged to consider applying to be a part of this course,” Mrs Foster said.

Water-logged land on a Tully banana farm has been transformed into a water quality treatment wetland which is starting to show promising results.

The constructed wetland is part of the Wet Tropics Major Integrated Project, which is trialling a range of treatment systems and methods to monitor and improve water quality in the Tully and Johnstone cane and banana growing areas.

Wetlands are known to improve water quality by removing nitrogen, mainly through the process of denitrification which involves bacteria in the soil converting nitrate in the water to nitrogen gas.

Tully banana grower Patrick Leahy saw potential for a constructed wetland on his 121-hectare farm.

“It was an unusable piece of land in a low-lying area of the farm. I knew a wetland would work well in that location but needed the support to make it happen,” Mr Leahy said.

With financial backing from the Wet Tropics Major Integrated Project, the constructed wetland has been made a reality for Mr Leahy, who has taken a proactive approach to improving water quality for over 15 years.

“I’ve got several sediment traps and grassed drains already across my properties. I’m happy to see that results to-date show that the wetland is doing its job,” Mr Leahy said.

The project partnered with Griffith University researcher Dr Fernanda Adame and her team from the Australian Rivers Institute to investigate and set a baseline for the performance of these treatment systems.

“The early indications look positive. The systems are starting to get the right conditions for the bacteria to remove nitrate from the water, and we are starting to see good levels of denitrification in the soil,” Dr Adame said.

“We assessed soil and water characteristics and potential denitrification rates at the end of last year’s dry season.

“Wetland species, bulkuru and grey rush, were planted at the site and a native, triangular sedge, is naturally vegetating the area.

“As vegetation establishes, the new leaves and roots of the plants will provide ‘food’ to these bacteria, which will result in improved efficiency of this wetland with time – removing nutrients from the water before it leaves the property,” Dr Adame said.

Bioreactors and nitrate sensors ignited interesting discussions on the banks of Banyan Creek earlier this month.

Tully State High School Agricultural Science students visited a Wet Tropics Major Integrated Project sub-catchment water quality monitoring station to learn more about the multi-million-dollar project happening in their hometown.

The year eleven and twelve students gained an insight into the multi-faceted project which is working closely with banana and cane growers in the Tully and Johnstone areas to trial a range of innovative treatment systems and approaches to improve water quality.

Teacher and Agricultural Science Co-ordinator at Tully State High School, Warren Giffin, said the excursion provided students with a better understanding of water quality testing methodology and analysis and addressed sustainability, which is part of the new senior Agricultural Science curriculum.

“This unique project is happening right on our doorstep, so it was a great opportunity for students to see the science firsthand,” he said.

“It’s important for this generation to appreciate and understand why water quality and soil health is important, because they’re our future leaders.”

Wet Tropics Major Integrated Project Water Quality Project Officer, Emma-Lee Harper, demonstrated a water quality sampling technique and explained the scientific aspects of the project’s Local Scale Monitoring Program.

“The questions they asked highlighted their degree of comprehension on the subject – it was impressive to see that level of knowledge,” Ms Harper said.
The project’s Tully District Extension Officer, Maria Ribbeck, discussed the importance of soil health and its correlation to water quality.

“As an agronomist, it’s encouraging to see students show an interest in soil health and eager to learn more about how growers are improving their paddocks.

A Moresby banana grower’s leading-edge farm transformation is turning heads in the Johnstone region.

Gavin Devaney from Bartle Frere Bananas has converted a 65-acre cane paddock into a best practice banana farm with innovative water quality runoff solutions.

Earthworks on the property, which is located beside the Bruce Highway just south of Innisfail, have attracted plenty of attention.

“People thought I was sub dividing the land with the amount of earthworks happening,” Mr Devaney said.

His aim is to improve the farm’s layout and reduce its environmental impacts while also maintaining productivity and profitability.

Supported by industry representative body Australian Banana Growers’ Council and the Wet Tropics Major Integrated Project (MIP), the Devaneys have implemented a combination of best management practice principles and innovative drainage solutions.

Mr Devaney said water quality was front of mind from word go. He met the cost of implementing the farm re-design while allowing the Wet Tropics MIP to utilise approximately two acres of productive land to fund and trial an innovative in-drain wetland on his farm.

The in-drain wetland system is being trialled to determine its ability to replicate the same nitrogen removal process that occurs naturally in a wetland, as well as the potential to remove sediment and pesticides from water flowing from agricultural land into local waterways.

MIP Johnstone Basin Coordinator Sandra Henrich said that many growers in the Johnstone region are implementing practices to improve their farms in line with best management principles.

Australia’s first international Bioreactor Forum was held in the Wet Tropics last month.

Interest in these innovative water treatment systems has spiked over the last two years, with the Wet Tropics Major Integrated Project (MIP) installing seven across the Tully and Johnstone basins.

The two-day event brought together researchers, technical specialists, extension officers, growers and funding bodies from Australia and abroad.

Day one included a visit to bioreactor trial sites on farms, where attendees interacted with landholders and delivery teams involved in the research, design and installation of the treatment systems.

Day two involved focused discussion on the role of denitrifying bioreactors in sustainable food production and potential strategies to enhance their performance.

The MIP’s place-based approach has modified traditional “textbook” wall and bed bioreactor designs and is trialling three other designs (in-drain, ag pipe and partial in-drain bioreactors), which were developed to suit the unique nature of Wet Tropics landscapes.

MIP Catchment Repair Coordinator Suzette Argent presented at the forum on designing bioreactors to fit within the Wet Tropics landscape.

“The input we receive from landholders has been a crucial part of the process,” she said.

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

“Farming is full of science and it’s rewarding to work alongside our farming community to trial water treatment systems that can improve sustainability, profitability and the quality of water flowing to the Reef.”

Ms Argent hosted forum delegates at a MIP bioreactor site on a Mourilyan cane farm.

“The field trip was a highlight for attendees because they could see firsthand how bioreactors can be implemented to complement farming operations and improve water quality entering adjoining waterways,” Ms Argent said.

Department of Agriculture and Fisheries Research Agronomist Rhianna Robinson coordinated the event and said they were pleased with the interest generated and contributions of everyone who attended.

“It was a networking and learning opportunity with local, interstate and international speakers sharing their experiences in installing bioreactors on farms,” she said.