Integrated orchard management (IOM) projects designed to get more sunlight into macadamia orchards, promote grass coverage on orchard floors, and manage water drainage are key to improving the industry's resilience and environmental sustainability.

“We work closely with our growers to help plan and implement IOM projects that have long-term benefits for macadamia production, profitability and environmental stewardship and sustainability,” says Mark Whitten, Marquis Macadamias grower liaison officer for northern NSW.

He said IOM combines three fundamental pillars of orchard management: drainage, orchard floor management and canopy management.

“Growers implement IOM to improve sustainability, control erosion, build healthy soils and canopy management to ensure adequate light levels to sustain grass cover on the orchard floor,” Mr Whitten said.

“Improving the light environment in the orchards also makes the environment less suitable for pests and diseases.

“This system also ensures orchard resilience in the face of extreme weather events, such as during the floods that hit the Northern Rivers region in NSW in February and March in 2022.”

Situated on the southwestern side of Alstonville in the Northern Rivers region, Marquis Macadamias grower Robert Mosse has spent the previous decade implementing IOM in his orchards.

The program was specifically designed to widen tree spacing within his orchard to improve light penetration, grass coverage, pest management, and more efficiently control the water flowing within the orchards by installing diversion drains.

Long before the floods came, Mr Mosse removed approximately 8000 mature trees.

“In the older orchards where the spacing was 7m x 4m, we removed alternate rows, and in some cases, we removed whole blocks, even where the spacing was 8m x 4m, and replanted using much wider spacing,” Mr Mosse said.

“Water control was extremely effective in the blocks where tree removal and profiling within rows had been completed. There were no visible signs of erosion within any of these blocks during the recent floods, and the water leaving these blocks was clean.

“We suffered some soil erosion in blocks where the spacing is still 8m x 4m despite the construction of diversion drains.”

He said upon completion of all remedial work, the spacing across his properties will vary between 16m x 4m and 10m x 5m.

“We believe in our situation 10m x 5m is probably the optimum spacing because this will allow for easy conversion to 10m x 10m spacing in the future in the case of some of the really big varieties,” Mr Mosse said.

Mr Mosse said though costly, the remedial work undertaken had been worthwhile.

“Prior to the floods, we started to see yields increase as well as the quality of the nuts. Despite the floods and prolonged wet weather at the beginning of this season, we were able to harvest during most of the wet weather, and our crop this year will exceed last year’s crop.

“However, there is no doubt when the floods hit, we lost nuts already on the ground, especially in those blocks where remedial work has not commenced.

“Wind damage was also significant in our region, and we suffered a loss due to a few trees being blown down, but most of the damage was caused by heavily laden branches being torn off by the wind.”

Mr Mosse attributes the fact that his orchards suffered less flood damage to the advice given to him by Phil Zadro in Bundaberg many years ago, where they often experience very heavy rain.

“Phil said to me at the time that keeping control of water flowing within the orchards was essential. Phil was absolutely right,” he said.

Mr Whitten said following the floods, it was inspiring to see the resilience of the region and the macadamia growers.

“Growers have been helping each other where possible, with a general acceptance of the situation and an enthusiasm to get back into farming macadamias,” he said.

“Most importantly, Marquis Macadamias has maintained communication with growers, ensuring they have someone to speak with about their situation and to receive tailored advice on harvest strategies and pathways to recovery.

“We have been able to support growers impacted by floods by working with our transport providers to ensure more options are available to get their nuts to the dehusking facilities or factories, as well as extending the opening hours for receivals at our factories.”