Introductory soil physics

[markyscott]

...just curious did wireme stay totally inorganic in all his applications ?...

I reread his post I linked and he didn't say for sure. I looked carefully at the images and it appears that it is not completely inorganic - it appears he's using some horticultural charcoal in his mix. The rest looks inorganic - clearly pumice and scoria - I couldn't see anything else. Perhaps he'll chime in and confirm.

His post is worth a read as he makes some salient points about how the AFP and WHC evolve over time as the soil gets populated with roots, mycorrhiza, and insects and the soil components begin to degrade. He also had an interesting speculation about whether there was feedback between the living community in the soil and the soils physical properties - in other words, does the biological community tailor the soils physical properties to achieve the best conditions for the population? Of course I don't know, but it was an interesting thought.

I terms of the rest of your post, I prefer to stick to the physics and not comment on anecdotal remarks about what has or has not worked well for individuals under their own growing conditions.

Scott

 

[wireme]

I reread his post I linked and he didn't say for sure. I looked carefully at the images and it appears that it is not completely inorganic - it appears he's using some horticultural charcoal in his mix. The rest looks inorganic - clearly pumice and scoria - I couldn't see anything else. Perhaps he'll chime in and confirm.

Hiya Scott.

Yep, at least 90 percent pumice and
scoria, always the chance that a bit of perlite or granite found its way in, I resift and reuse without paying much mind to what is there, more particle size.

Charcoal would either be from the indoor wood stove, the outdoor fire pit or from a burnt old nurse log in the woods.

Usually I have some organics 10-15 percent. Depends on mood and availability, definitely have potted trees without organics so can't say for sure about the pictured rootball.

Organics would either be dougfir bark semi decomposed from the bottom of the bark pile by our sawmill or chunks of cubical redrot wood from coniferous nurselogs in the woods. Usually the later, I'm guessing the tree above had some of that and the pill bugs chewed through it over time turning to pillbug poop I guess?

Fertilizing would have been liquid organics and some llama or deer pellets on the surface.

Oh, and thanks for the great thread so far!

 

[0soyoung]

Oh, and thanks for the great thread so far!

Yes, I agree!

I do wish we had some data to go with the theory, though.

 

[markyscott]

Yes, I agree!

I do wish we had some data to go with the theory, though.

We'll get there. I'm a working stiff so you may have to wait until the weekend so I can compile it.

Scott

 

[A Random User]

We'll get there. I'm a working stiff so you may have to wait until the weekend so I can compile it.

Scott

You are doing a great job!
These type threads, they are a ton of work, I know... I appreciate, as I am sure everyone else appreciates it!

 

[coh]

I want to know who is going to search for and start mining those akadama deposits in the Pacific NW.

Scott, thanks for taking the time to put this information together.

 

[markyscott]

Let's talk about Turface.

Turface is a brand name for a calcined clay. Calcined clay is another manufactured product like Haydite. However, the process of calcining is different than the process of sintering. Both processes involve heating a sample to a specific temperature, but with calcination, the goal is almost always to affect a phase change. In other words - one mineral goes in, a different mineral goes out. Sintering generally means heating to make a substance hard and dense, but there's no phase change.

To make calcined clay they start with a clay mineral called Kaolinite which is a common clay mineral on the earths surface. It's a very pure clay mineral having a chemistry of 1 part Al2O3 and 2 pars SiO2. But the mineral is hydrated, having 12% crystal bound water. They take an ultrafine natural ample and heat it to temperatures of 1300 degF in a rotating kiln. At these temperatures the kaolin is completely dehydrated (all the hydroxyl ions are boiled away) forming a poorly crystalline metakaolin.
high temperatures in a kiln. This process changes the properties and alters the size and shape of the kaolin particles. That's how calcined clay is made - very similar to Haydite except it's fired at a much lower temperature, heated more slowly and starts with a different starting material.

Here's what it looks like:


Turface is:

1. A pottery - it's chemically inert
2. Has some microporosity due to the manufacturing process
3. Is very strong and hard - it won't break down over time
4. I pretty light weight - it won't add a lot of weight to your pot
5. Is angular to subangular (the grains aren't rounded in texture)
6. Comes only in fairly fine grain sizes
7. Is cheap and readily available.

Here's some data on Turface size fractions. I purchased a single 40lb bag of Turface Athletics MVP from Ewing Irrigation, sieved the bag into different size fractions, and measured the portions of each fraction. I sieved the entire bag. Here's how the sizes broke down by fraction:



Scott

 

[markyscott]

Here are the size fractions for akadama (Medium grade double red line brand purchased from Wee Tree)



Scott

 

[0soyoung]

Turface specifies the particle size distribution for MVP, in mesh sizes. If we say that 1/8th inch is 8 mesh, their specs amount to 52% at 8 mesh and smaller. The balance (48%) larger than 8 mesh. In other words, I think there is agreement with your results (nominally 8 mesh or 1/8th inch or 2.3 mm), though their spec provides a bit more resolution - I'm happy to know

 

[markyscott]

Turface specifies the particle size distribution for MVP, in mesh sizes. If we say that 1/8th inch is 8 mesh, their specs amount to 52% at 8 mesh and smaller. The balance (48%) larger than 8 mesh. In other words, I think there is agreement with your results (nominally 8 mesh or 1/8th inch or 2.3 mm), though their spec provides a bit more resolution - I'm happy to know

All I know is that it takes a lot of sieving to get a useable split in the 3/8-1/4" size fraction. But for you guys I did it. I just have that much love for the folks on Bonsai Nut!

But never again.

Scott

 

[Anthony]

In pottery use / sinter bonding is the first stage, removes water of crystallisation.
However at around 650 deg.C [ 1202 deg.F ? ] Kaolin type clays would be easily friable.
[ going on memory here - feel free to correct ]

If pottery down here is fired to 650 deg. C and it is an earthenware, in use as a plant pot,
decay of the body will set in within a month. The fired body begins to flake and powder.

Explains the problem popping up at times with Turface.

At 900 deg.C [ 1652 deg,F ] earthenware does not give that problem, but suspect 1100 deg.C [ 2012 deg.F ]
is better for Kaolin type clays.

Mark it would help the Europeans if you also stated the facts in mm's, I have to keep translating
lengths and temperatures for both sides of the pond, as they say it.
Good Day
Anthony

 

[Andrew Robson]

OK - so here's another fun fact. We talked about what water saturations look like in the pot immediately after watering. What happens during the rest of the day?

To talk about this, we need to introduce another concept - hygroscopic water. Here's what we know so far - when we water all the pores are filled and the soil is close to saturation. When we stop watering, the gravitational water drains away and the soil is at field capacity - the so called "irreducible water saturation" (except it's not irreducible). This capillary bound water is what is available to the plant. So during the day the plant will draw water from the pore space and the water saturation will drop below field capacity. It will continue to fall until all the capillary bound water is gone. But the water saturation is not zero. There is still a small amount of water in the pore space held by capillary or electrostatic forces so strong that the plants can't access it. This is called the "wilting point". The remaining water in the pore space is called "hygroscopic water". Here are the three saturation states; 1) fully saturated, 2) at the field capacity, 3) at the wilting point (aptly named).

View attachment 118927 View attachment 118928 View attachment 118929

Too long at the wilting point and plants will not recover turgidity when you water them again. So your goal is to maximize the time the plant spends at the optimal air-filled porosity above the wilting point without killing yourself by watering every 15 mins. Tricky balance.

Scott

Scott,

Do you happen to know why pumice has such a high capillarity? We've done some experiments in Michaels yard, and found that the capillarity if pumice is pretty remarkable.

 

[markyscott]

Scott,

Do you happen to know why pumice has such a high capillarity? We've done some experiments in Michaels yard, and found that the capillarity if pumice is pretty remarkable.

Hi Andrew. I'll definitely get into pumice. We'll also determine the AFP and WHC of some of these commonly used materials for soil medium. And I'll show you a simple way you can do it on your own. But I many have partially answered your question earlier.

BTW - feel free to post the experiments you've done with Michael - this is the thread to do it. With earth materials like pumice though, there might be a tremendous amount of variability. Can you share where your pumice comes from?

Scott

 

[markyscott]

...Mark it would help the Europeans if you also stated the facts in mm's, I have to keep translating lengths and temperatures for both sides of the pond, as they say it...

Good point Anthony. I will do so. Thanks for the reminder.

Scott

 

[Anthony]

Hmm, my question here would be what are the inorganics that do not decay over time with usage ?

AND I figured out how to use the Akadama -------------- simple ---------------- when you repot, and here
one has a core of durable inorganic, cut a piece of screen to fit around the core of your tree and fill
the pot with akadama at the base. Rest plant and screen, fold screen up the sides and then fill the
rest of the pot with mix.

That way you get the benefits of your akadama mix, when it decays to be problematic, lift and the
screen acts as the boundary to the cut off point.

Sort of colander in a bonsai pot. Hah, foolishly simple.

Works when using peat moss mixes to keep thirsty Fustics happy.

Had a chat with our nursery folk. The way plants are potted up is very simple - small pot / plant pot
bound, to slightly larger ................
There is no real chance of a perched water table or other water problems since the plant has mastered
the soil.

It is also long time known that placing a plant in a large mass of soil will often kill it. [ 1970 Canadian garden books ]

So if at repotting time you are actually BARE ROOTING and not not just cutting say an 1" [ 2.5 cm ]
all around and underneath.
I can see the soil problems that start up and especially with old trees.

Now how long before pumice degrades in use ?
Perlite doesn't even make a year in our climate, roots smash it to bits.
Good Day
Anthony

* All delivered in a fiendishly wicked tone -

 

[markyscott]

Hmm, my question here would be what are the inorganics that do not decay over time with usage ?...

Akadama will break down over time, but I've not found that to be a problem on time-scales of at least 4-5 years in Zone 9/10 in my climate. Here's a picture of soil components that had been in a pot for 4-5 years when I took the picture:



The akadama looked like it held up pretty well as did haydite, pumice, scoria, and seramis. I imaging that turface would also. You can see where I crushed a couple of akadama grains - they're still soft.

I'm not sure why perlite would break down as rapidly as you say. It's used all the time by the nursery industry here. But I don't use it as a soil component so I have no observations to comment.

Scott

 

[markyscott]

...AND I figured out how to use the Akadama -------------- simple ---------------- when you repot, and here one has a core of durable inorganic, cut a piece of screen to fit around the core of your tree and fill the pot with akadama at the base. Rest plant and screen, fold screen up the sides and then fill the
rest of the pot with mix.

That way you get the benefits of your akadama mix, when it decays to be problematic, lift and the
screen acts as the boundary to the cut off point.

Sort of colander in a bonsai pot. Hah, foolishly simple...

I've never tried this and I never will.

Scott

 

[markyscott]

Had a chat with our nursery folk. The way plants are potted up is very simple - small pot / plant pot bound, to slightly larger ................
There is no real chance of a perched water table or other water problems since the plant has mastered
the soil...

The height of the saturated zone at the bottom of the pot is controlled by the size of the pores in the soil medium, not by whether or not a plant has "mastered the soil" - although I don't really know what that means. If you up pot, it's likely that the fresh soil will have different capillary properties than the used soil. So it's possible that there will actually be two "water tables" - one at the bottom of the pot, another at the bottom of the old rootball. It really depends on whether the old rootball has higher or lower capillary pressure than the new rootball. That's purely a function of the size of the pores in the soil medium(s), which in turn is a function of the parameters I posted earlier - 1) the grain size, 2) the grain shape, 3) the sorting, and 4) how far you are above the bottom of the pot. In used soil, the pore size changes are unpredictable as they will change due to biological activity, soil compaction, and component degradation as well as other factors.

Scott

 

[markyscott]

...It is also long time known that placing a plant in a large mass of soil will often kill it. [ 1970 Canadian garden books ]....

Care to speculate about why this is the case?

Scott

 

[Anthony]

Mark,

apologies if I am confusing you. We just opened the compost heap, and touched less than 1/4 or the 10 x 10 feet
got 20 buckets of sifted stuff ---- wahoo.

The feeling of happiness is spilling over. Apologies.

You also have to remember that we two nuts down here do a great deal of experiments on everything.
Yet we have trees, 30+ years from seed or cuttings ------ so hopefully we are doing something correct.

We started using the mesh technique a few years ago, as a variation of the colander in the ground growing
technique. It allowed us to retain the bonsai pot shape, but also keep the moisture level up for the
trees that have heavy canopies and very thin leaves.

Your question -
Possibly the plant drowns in too much water.Soil is too wet to control. Especially rain and high humidity.

When you up pot a heavily root bound plant, you only move up to a pot so much larger. Depends on the plant,
So for example say a Fustic, which is thirsty, a 1" of peatmoss based soil all around and under will allow it a year or so of easy
life. It is supposed to take feeder roots 24 hours to regenerate or grow out.
I don't think that will bother a plant too much as soil goes.

Additionally the core being root filled and as such water deficient should draw water into itself, especially in
hot sun and wind [ speculation ] but please note these are also our day to day growing conditions for the
bonsai. House is in a wind channel and exposure is full sun 6 to 6.

Back to life down here. It is getting cooler at night ----------- Autumn and soon Winter. Happy days down here.
Soon the landscape will turn orange and vermilion with flowers and the teak will be leafless.
Good Day
Anthony