Carnarvon trials push jackfruit growing to its limits
The picturesque backdrop of a Carnarvon sunrise or sunset belies the extreme environmental conditions under which research scientist Dr Melanie Ford and her team from the Western Australian Department of Primary Industries and Regional Development (DPIRD) have operated their jackfruit variety research trial site.
The research station deals with extreme heat, cold winters, light intensity, and wind pressure, but this demanding subtropical desert climate provided an ideal setting for understanding the limits of what the jackfruit crop could withstand.
Established in November 2021, the Carnarvon site is part of the Cooperative Research Centre for Developing Northern Australia’s (CRCNA’s) Developing Next-Generation Orchards project. The project brought together expertise from multiple government agencies, and industry organisations.
Along with Carnarvon, the project has another Western Australian site in Kununurra, with a further six sites across the Northern Territory and Queensland.
The project is investigating high-density and trellis planting systems, varieties, and irrigation methods to examine production capacity, profitability, and cyclone resilience.
As the trial moves towards completion this year, it’s clear the research has produced some insightful results.
While the benefits of trellising may be realised in other locations, in Carnarvon tying trees to the trellis formed more of a two-dimensional branch structure, reducing canopy cover, and exposing the plants to sunburn.
Increased exposure to Carnarvon’s high light intensity did however provide an opportunity for the team to test different techniques to reduce sunburn. Namely, co-planting papaya to provide shade (and a secondary crop), as well as applying a kaolin clay spray on the jackfruit trees like sunscreen.
Dr Ford said it was envisioned that the “clay particles will be able to reflect sunlight and stop burning on the branches and leaves of the trees.”
This experiment proved effective during the tree’s establishment period.
The incursion of phytophthora on the research block presented another challenge, but again the researchers used this as a learning opportunity, successfully managing the pathogen, which attacks plant roots, through soil treatments and adding nutrients to the plants.
“The silver lining to our pathogen issues with this block is that we now have learnt different management techniques we can use to combat them, and this is information we can pass directly onto the growers,” Dr Ford said.
CRCNA Chair, Ms Sheriden Morris said this is a great example of the collaboration occurring across Northern Australia, aiding agricultural diversification and climate resilience.
“Projects like this provide growers with sought after management advice, as well as strategies to mitigate the risks associated with tropical cyclones and severe weather in the north.”
Although jackfruit was the catalyst crop in this trial, the lessons about production methods, dealing with climate, and managing diseases are useful to growers of different orchard crops in a variety of locations.
The Demonstrating Next-Generation Resilient Orchard Production Systems for Tropical Crops project is funded through the CRC for Developing Northern Australia (CRCNA) as part of the Australian Government’s CRC Program, and being undertaken in collaboration with the Queensland Department of Agriculture and Fisheries (DAF), Northern Territory Department of Industry, Tourism and Trade (NT DITT), Western Australia Department of Primary Industries and regional development (DPIRD), Manbulloo Limited, Aus-Ex Fruit, Northern Territory Farmers Association (NT Farmers) and Growcom.
