Please Help With a Gameplan to Save the Last of Our Macadamias

[agroventuresperu]

Here's some context from another thread I responded to:

Proteoid roots in the macadamia are characteristic of most species of the Proteaceae.  These are highly efficient roots evolved to survive in very poor soils.  The addition of fertilizer can overwhelm the plant and simply be toxic.  Of my 40 or so trees of different varieties, they rarely see any fertilizer.  Their soil is just old beach sand (with a slight acidic flavor)

In our context, I had originally assumed aluminum toxicity due to the low pH of our soil here, hence the addition of dolomite. We have some areas that are clay, fertile and less problematic with lots of humus, while some other areas are pretty soggy/slightly swampy yet sandy at the same time. We started out with just a small amount of compost mixed with the native soil when we originally planted them. We planted roughly 100 from seed-grown plants started in a nursery. They were planted all over the property in a variety of different locations and soil conditions. No pattern emerged to suggest why some might have survived whereas others did not. They were all pretty healthy in the nursery before planting. When we transplanted to the field we achieved the following results: Most died, lots have shown extremely slow growth, and only a couple have shown moderately slow growth. I don't think our problem here was overly fertile conditions, as our original soil analyses before planting indicated pretty typical nutrient deficiencies that one might expect of deforested jungle turned to cattle pasture for 1 or 2 decades.

If Macadamia grow well in coastal central California on sandy soil, I'm guessing they might require better drainage than avocado. We had a lot of Avocados die on our property, but we also have plenty that have shown excellent growth at different places on the property. I'm not familiar with Macadamia's native growing conditions in Australia.

Doing another round of Maintenance on our property, last week, I came across three Macadamia trees that we planted over two years ago that are still alive. One is extremely small, the other two are also pretty small but look healthy. I'm not sure why, but the Macadamias here have only grown a few inches per year at best. Some may have only grown a few millimeters. I'm not sure what they need. The above comment makes me wary to add any more fertilizers of amendments.

Was thinking about just mulching them with sawdust, but I'm worried if I just look at them wrong they might decide to stop being green. Out of the seedlings that we planted originally, probably at least 90% have died. I still have about another 5 or 6 hectares of plantation to look through to see if there are any more survivors out there.

It's not something that's available as a nursery plant in this country, so they're basically irreplaceable. Would be a shame not to at least save a couple of them.

[pagnr]

There are plenty of these type of resources in Australia, Macadamia is a major crop in some areas.
http://era.daf.qld.gov.au/id/eprint/1964/4/mac-growing_guide_Part4.pdf
This may be of interest re fertiliser interactions
https://www.researchgate.net/publication/349647218_Phosphorus_and_pH-induced_Iron_Deficiencies_in_Macadamias
Macadamias are pretty widely grown in Australia outside of their original Rainforest areas.
Not sure what issues you are having ? Are the young plants sheltered or exposed ?
Mulching with wood waste might benefit. Composting Macadamia shells might benefit with Mycorhizza.

This relative of the Macadamia is from South America
Genuina avellana, Chilean hazelnut, avellano chileno https://en.wikipedia.org/wiki/Gevuina

[achetadomestica]

I have some airlayered macadamia trees. I have been struggling for
several years and killed several trees along the way. Now I seem to have figured out
their needs and last Winter when we were below 32f for over 5 hours I lost 2 more trees.
They love acidic soil and I add a handful of sulphur pellets to the soil every month and
they love water. If I water them daily they put on new growth. This past year I have been
giving them a cricket frass for fertilizer and they are nice an dark green and growing
with the daily water and sulphur. 

[carolstropicals]

We have a company here, in Houston that sells leaf mold.
I use it safely all the time along with organic alfalfa.
Found at tractor suppy.
Carol

[pagnr]

Since you grew the Macadamia trees from seed, how did they go as nursery trees in pots before you planted them out ?
Sounds like they were reasonably healthy ?
Did they then go backwards after planting out ?

[Johnny Eat Fruit]

Sounds like neglect to me. How often do you care are water your Trees? You don't give much information on what you do to take care of them. Have you done your homework regarding Macadamia Trees soil and water requirements?

As previously mentioned Mac trees love water and low ph soil.

Good Luck.

[agroventuresperu]

Well that's what's so puzzling. We're here in the rainforest with low pH soil and abundant year-round rainfall. I thought my signature or avatar on here gives the stats of where I'm located. They seemed to be doing okay in the nursery before planting. They were planted out while still very small. Maybe it's our weed competition. Perhaps macadamias are a species that is weakly competitive with grass and herbaceous weeds. 

Anyway, the thing about low pH makes sense considering the bad reaction when I added dolomite to a lot of the trees last year. The phosphorous from our guano de isla fertilizer sounds like it could have hindered them. In any case, they just suck. The ones that are left look perfectly healthy, but they hardly do any growing. I don't remember what iron deficiency looks like, but I believe it leaves some physical indication on the leaves. I've got an expensive imported mycorrhizal product that I could add to their root zone, but don't want to spend too much money on them in vain. Certain trees need to give a little to get a little around here. I hate babying trees that refuse to ever grow properly.

What growth rate have you all acheived with Macadamias? Is it easy for people to get over a meter per year. Like I said, ours have only grown a few inches per year at best. The tallest one after two years in the ground is probably only 1.5-2ft tall. Maybe we just have some weird soil biology here that doesn't favor them? Do they need longer daylength to grow? We're always 12hr days.

[pineislander]

The Brachiaria grass you have is known to be allelopathic.

[achetadomestica]

Is Macadamia grown in that area?
If there are producing trees in that area would it be possible to airlayer a tree?
A macadamia from seed would take 10 years to produce if the tree was growing.
At the rate your trees are growing it might take 50 years. If you insist on growing
a seedling then I would consider repotting a tree and watering it daily.
I have planted trees in the past that ended up crashing and I have also planted
trees that would not grow for whatever reason. I dug them up and repotted and
they started growing in a pot?
Also I would water one of the trees that you planted daily with a couple gallons of water for a month.
You should see new growth by then. I have a tree I just planted and I water daily and
it is putting new growth out in less then a month

[agroventuresperu]

The Brachiaria grass you have is known to be allelopathic.

I know brizantha is, but wasn't sure about decumbens.

[agroventuresperu]

Is Macadamia grown in that area?
If there are producing trees in that area would it be possible to airlayer a tree?
A macadamia from seed would take 10 years to produce if the tree was growing.
At the rate your trees are growing it might take 50 years. If you insist on growing
a seedling then I would consider repotting a tree and watering it daily.
I have planted trees in the past that ended up crashing and I have also planted
trees that would not grow for whatever reason. I dug them up and repotted and
they started growing in a pot?
Also I would water one of the trees that you planted daily with a couple gallons of water for a month.
You should see new growth by then. I have a tree I just planted and I water daily and
it is putting new growth out in less then a month

I heard there used to be a study a number of decades ago outside Moyobamba where they introduced Macadamia, but it was unsuccessful. Not that the trees didn't grow, just that the stakeholders lost interest, because everyone favors quick-producing stuff like rice instead. I think most of the plantings were destroyed. I do know of one tree, but it is located in downtown Moyobamba in front of a government building. Apparently some people have learned that the seeds are delicious, as you can never find any on the ground under the tree. I'm not sure it would be feasible to take cuttings from the tree, as all the low hanging branches are pruned off.

Hard to believe water could be the limiting factor here. We just got six inches of rain last night and about another inch just now. We planted 144 total at random spots all over our property. Just found another small one today that's growing in an extremely soggy area of our property close to where we have a Camu Camu planted.

Since there are so few left, I was thinking about adding a tablespoon of mycorrhiza powder to the root zone of each one, a bucket of sawdust on top of that, and sheetmulch with cardboard to give them an advantage over the weeds. They don't seem very competitive with grasses or herbaceous weeds.

[agroventuresperu]

I have some airlayered macadamia trees. I have been struggling for
several years and killed several trees along the way. Now I seem to have figured out
their needs and last Winter when we were below 32f for over 5 hours I lost 2 more trees.
They love acidic soil and I add a handful of sulphur pellets to the soil every month and
they love water. If I water them daily they put on new growth. This past year I have been
giving them a cricket frass for fertilizer and they are nice an dark green and growing
with the daily water and sulphur.

"Cricket frass"?

[Gone tropo]

hey mate cant help you with the macadamia as i dont grow them however in australia the commercial areas are a lot cooler than where you would be.  I do however understand your frustration as I have the exact same thing happening at my place with illama and sugar apples.  My illama all sprouted just fine which is supposedly the hard part they were nice and healthy until i planted them. Several have died and the few left dont grow have black leaves and are just sad looking.

Ive just been trying a process of elimination trying to add one thing at a time to see what the are missing or lacking still yet to find the answer.  Strange cos all my other fruit trees thrive on the same soil.  hopefully you can find what the problem is before its too late.

[achetadomestica]

cricket frass is cricket manure

https://www.gardenandgreenhouse.net/products/natural-cricket-frass-fertilizer-4-2-2/

I agree if your trees are getting rain daily then it should be enough.
My rainy season is spotty and the days it doesn't rain I water. I lived next to
an experimental macadamia farm at my previous residence. That guy
was watering a smaller amount twice a day. He also had a watering system that
injected acid to lower PH.
Where did your original seeds come from?
I would ask the people in the governemnt office if you can airlayer the
existing tree. Maybe for a small fee they would? If the branches are high it
is better so passerbys can't disturb. Bring a ladder and do it right.

[pagnr]

The original seedlings were growing ok, as you say. Did you rare root plant in the ground or dig a hole and drop the rootball in ?
Any root setback, or problems with roots moving into soil.
Have you ever tested the soil for Phosphorous levels ? It might be higher than Australian soils overall.
Then again the nut bearing tree you mention at the office garden seems to be ok ?
I would try methods of biological stimulation around the trees.
If small plants they are only using a very small area of soil each, not the whole property.
Possibly a mix of mature compost and sawdust or bigger chips worked into the soil.
You can overcome Phosphorous level problems in containers by using low P,  NPK fertilisers.
P of 2% or lower is commonly used for Citrus seedlings to avoid induced Iron deficiency.