In mid-April 2020, 11 young macadamia trees had been transplanted to the Bundaberg Botanical Gardens. These trees are a sub-species of Macadamia jansenii, as are the commercially grown ones. They are being grown to ensure that all genetics of the native macadamia tree are preserved, not just the commercial ones.
Holes were dug, the trees placed and they were irrigated and mulched with wood chips — all standard procedure. From there on, they received the same treatment as the rest of the gardens. That included regular watering from the park’s watering system.
In May 2021, two had died and the others were not doing well, mainly due to wind and soil conditions. Topsoil was basically not present and the silty loam subsoil was very compact and dense. On 10 May 2021, two of the surviving nine trees were treated with DIY Soil-biology Booster tea and some minerals. Nothing else was changed.
On 30 August 2021, 112 days after treatment, they were inspected again. Another three untreated ones had died and the remaining four were not doing well.
The contrast with the treated ones could not be starker. (The same white board was used in all photos.)
In May, the trees had shown leaf chlorosis and a small amount of growth. This was taken into account in the treatment. The soil into which they were planted showed no crumb structure or softening which indicates an almost complete lack of soil-biology.
The treatment consisted of:
A compost tea using the DIY Soil-biology Booster starter (1 Litre/tree), (now called DIY Instant Compost Tea)
Calcium (10 g/tree of very fine lime)
Zinc (10 g/tree of zinc sulphate heptahydrate)
Humic acid (10 ml/tree)
Sea Minerals (10 ml/tree)
The tea and minerals were watered-in with a watering can up to 0.5m around the tree.
112 days after treatment, the treated trees showed two to four times the growth of what they had been and had healthy leaves. Most importantly, the top 10 mm of soil showed crumb structure and more roots. This indicates that the introduced soil-biology had ‘taken’ and multiplied rapidly.
The experiment confirms our view that to get healthy trees, we need to increase, balance and feed the soil biology. This requires a much wider range of minerals than has been realised until recently. And where the biology is not present, it can be re-introduced in a much shorter time than is currently believed.
To give a human perspective how fast that can happen, the tree below grew about one metre in 112 days, from being a stunted one about knee-high to what the photo shows.
To summarise:
More than double the growth, no yellow leaf deficiency and softening soil
All that in 112 days and in lifeless, compact subsoil — and after 13 months of no growth whatsoever. It shows the awesome power of Nature when given the right ingredients.
Post script
For reasons unknown, all macadamia trees have been removed.
