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.