In a first for the industry, an Australian macadamia operation has demonstrated

that practices to promote soil health and fertility can significantly reduce greenhouse gas (GHG) emissions and increase GHG removals via soil organic carbon (SOC) improvement.

Carbon reductions refer to a decrease in GHG emissions, achieved by using less fertiliser, chemicals, or energy to produce the crop.

Carbon removals refer to the capture and storage of CO2 from the atmosphere, in this case, via soil carbon sequestration.

Hinkler Park Plantations, a 3,000-hectare macadamia farm based in Bundaberg, Queensland, achieved total greenhouse gas (GHG) reduction and removal of 17,670 tonnes (t) of carbon dioxide equivalent (CO2e) between 2020 and 2021 across its entire macadamia production system through carbon sequestration and by cutting energy and fertiliser use.

This is the equivalent to offsetting the emissions from 4,236 passenger vehicles for an entire year.

Hinkler Park Plantations Queensland general manager and Marquis Macadamias director Clayton Mattiazzi said by going back to basics, Hinkler Park Plantations – also a supplier to the group –  has completely revolutionised its farming operations.

“This time eight years ago, we were struggling with soil health, tree health and yields. By implementing biological farming practices, we have completely reinvigorated the health of our farm and quality of our macadamias,” Mattiazzi said.

“We did this by creating a media of nutrient-rich material to optimise growing conditions for our trees. The key to this was repurposing the excess organic matter within the farm: prunings, inter-row grass clippings and nut husk were all moved back under the tree into soil to compost this material into food for our trees. This activity is supported with large anaerobic composted mulch made from excess farm waste.

“What we have created now is a farm that sequesters more carbon than it produces, preparing us for climate change by building a biologically healthy and more robust farming system.” An independent audit conducted by sustainable food certifier Carbon Friendly found the GHG emissions intensity of macadamia nuts produced at Hinkler Park reduced from 302 to 2,816kg CO2e per tonne of macadamia between 2020 and 2021.

Clayton Mattiazzi at Hinkler Park Plantations in the Bundaberg, Queensland, Australia, where a massive reduction in greenhouse gas emissions has been achieved through biological farming practices.

The Greenhouse Gas Emission Reductions & Removal Enhancements Report found that soil carbon improvement contributed to the removal of 2,935kg CO2e per tonne of macadamia nuts during this period.

Marquis Macadamias growers’ on-farm sustainability initiatives include:

  • Water use efficiency – macadamia farms in sub-tropical regions rely heavily on the area’s natural rainfall. In the Bundaberg region, and in South Africa, growers supplement the rainfall with irrigation sourced from storage dams and boreholes, using the latest in monitoring systems to apply the right amount of water when needed. Marquis has recognised the need for moisture conservation within its orchards, as each tree uses an average of 45l of water per day in winter and 60l of water per day in summer.
  • Healthy soils on farms – compost, woodchip and woodchip manure blends are used to improve soil health and structure on the macadamia farms. Trees are pruned to ensure grass grows between the trees on the orchard floor to reduce erosion. Various cover crops are also planted between the rows to encourage biodiversity, provide a varied diet for pollinators, and encourage micro-organism populations in the soils.
  • Supporting pollinators – bee gardens are developed to provide pollinators with a constant source of food, especially when macadamias are not in bloom. The gardens serve to protect wild bee populations and provide a safe environment where they can flourish and multiply. Great care is taken to ensure that any crop protection chemicals are only used when bees are not in the orchards.
  • Waste minimisation – on farm, growers add the macadamia husk under trees to improve soil health and to compost mixes. When pruning, growers chip branches to use as mulch. All macadamia shell from the factories is used either as renewable fuel to provide energy to various processes including providing heat to dry nut-in-shell, or is milled into stockfeed.
  • Integrated Pest and Disease Management (IPDM) – IPDM is central to successful and sustainable pest and disease management. IPDM involves careful monitoring of crops to identify areas of pest and/or disease activity. If monitoring finds that pest and/or pressure is above critical thresholds, these areas are targeted with various control strategies. Marquis growers focus on maximising the use of cultural and biological control agents, where appropriate, to minimise the use of pesticides.
  • Integrated Orchard Management (IOM) – on farm, growers use IOM, which combines three fundamental pillars of orchard management: drainage, orchard floor management and canopy management. These pillars work together to minimise soil erosion, build soil health, reduce orchard suitability for pests, increase biodiversity and habitat for beneficial insects, and ensure healthy and productive trees.
  • Self-Audit System – Marquis Macadamias has a self-audited quality improvement system in place that all Marquis Macadamias growers must complete at the start of each year.