Macadamia Nuts: 35,000 Mature Trees. Elimbah/Glasshouse Mountains QLD

Mike Cooper took his first step toward TM Agricultural during the 2014 season. Based on the early trials carried out on Gympie orchards and results on other crops. He purchased sufficient TM to apply 1 ltr/ha across the planted area, in three applications. The Mr Macadamia enterprise is made up of five orchards, some separated by up to 20kms distance. The trees are all approaching thirty years. The orchards are non-irrigated. When Mike took over the orchards about twelve years ago. The general condition of the orchards, tree and soil health was poor. Mike monitors every aspect of activity in the orchards, leaving nothing to guess work. This practise has paid dividends and it would be fair to state that few have a greater understanding of the idiosyncrasies of macadamias.

Mike’s Focus

Mike’s focus has been to build the strongest possible buffer against increasingly variable weather conditions. Through improved soil health and orchard floor condition. This is a tricky business as thirty year old macadamia trees are large. And have a mind to produce a larger canopy rather than more nuts. The size of these trees, and the inherited close planting density inhibits light penetration to the orchard floor. No grass cover then leaves the orchard floor subject to severe erosion. Featuring the loss of irreplaceable topsoil and costly nutrients.

This scenario dramatically inhibits the production from the orchard, due to exposed roots and reduced root mass in the top 50 mm of soil from which the trees draw their nutrition. Of necessity the trees are mechanically pruned every second year. To allow some light onto the orchard floor and into the tree canopy. Where orchards are allowed to “canopy over” production drops away dramatically. Mike has taken positive, costly action to address the issues, applying compost and carrying out profiling between the tree rows to ensure good root coverage and management of water flow. He also carries out mechanical aeration (spiked) as a matter of course.

2016

It is fair to state that Mike had never seen anything quite like what has happened in the orchards from the time TM had been applied. The developing phenomenon escaped Mike’s attention for a short while. Until a visitor to the orchard queried Mike about what he had done to suddenly grow grass across the interspace between tree rows. This grabbed Mike’s attention and a thorough check of all orchards quickly established an unfolding revolution occurring across the orchard floor areas. Tree health was increasingly stable and strong.

2017

Inspection with Mike confirmed that there is no longer a single row bare of grass growth across the total 100ha of trees. This includes several areas which had NEVER grown grass in Mike’s time on the orchard and are now supporting a prolific growth. Mike explains that the orchards are all slashed consistently, even during dry conditions. The growth rate and density of the grasses and clover has been startling. And growth is regularly in excess of 600mm in places when conditions are favourable. Grass has also penetrated further under the tree canopy. And some herbicide has been reintroduced to clear the harvest area immediately under the trees. Mike chuckles when he notes the “mixed blessing” with two mulchers going flat out around the clock to manage the orchard floor preparation pre harvest.

His comment was that he did not believe just how much grass there was until he heard the mulcher “screaming” under the mechanical load. It was also interesting to note the difference in the vitality of the grass within the TM treated rows and the external headland areas. Most importantly, this vitality is obvious in the trees. Mike is a little in awe of the fact that the trees and the potential crop have held up so well. Despite very dry and erratic growing conditions.

2018

Mike comments that the quality and species of grasses within the orchard has changed. With stringy and less persistent varieties being replaced by preferable stronger species. This mirrors the experience in pasture under grazing. Species not seen for many years in some cases, have reappeared. The big buzz for the 2018 season has been a record crop for the combined orchards. TM does not stand alone as a silver bullet in this situation. But it is obvious that it is a major contributing component in production and the correction and preservation of orchard health.

2021

The season produced an unexpected bumper crop in excess of 500 tonnes. Tree health has continued to improve across the seasons. Mike attributes a good portion of this outcome to the continued use of TM underwriting his attention to small regular adjustments to micro elements when required. Importantly, inorganic fertilizer input has been reduced by 40% across that period. Continual improvement in soil health and biological activity is providing the full compliment of nutrients required. Mike inspects the orchards every two weeks and a visual assessment dictates any small addition of micro elements required. The overall benchmark for the orchards is now evenness of the trees. The buffer of strong soil condition and fertility quickly reveals any minor issues which are boosted with small additions of micro nutrients as required.

It is no longer possible to maintain a grass cover in the 7m rows due to the density of the trees but continuing strong production from those trees has precluded any move toward tree removal to this time.

Michael’s personal comment: For the first couple of seasons it seemed TM was making a difference. After seven years of careful monitoring, the results are beyond question.

Brice Kaddatz
Macadamia & Hortcultural Services.
Gympie. Mob 0438 861198