The Water absorption of 4 Bonsai Soil Types

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The Water absorption of 4 Bonsai Soil Types

This is a test report on the water absorption capacity of 4 common bonsai soil types. The tested soil types are; Akadama, Kiryu, Kanuma & Seramis.



Short Description of soil types

Akadama:
Akadama is type of red clay imported from Japan. It comes in several qualities, fired and unfired. The unfired variety can absorb more water, but will break down quicker in the soil. Used in the experiment was a hard double-brand Akadama type.

Kiriyu:
Kiriyu is a hard volcanic soil with a high lime content, also imported from Japan

Kanuma:
Kanuma is a yellow soft volcanic soil with a high acidity, usually used for acid-loving plants like Azaleas.

Seramis:
Seramis is a brick-orange high-fired clay granulate, with a high water retention capacity, which will not break down in the soil over time.

Testsetup

Initially all soils have been sifted to get an even granular size for all types.
Removed were all particles smaller than the small size standard bonsai sieve, and all particles larger than the medium size standard bonsai sieve.

In a secondary experiment I sieved both the bag of Kiriyu as well as the bag of Kanuma in four different sizes. Fines, 1-2mm, 2-4mm, >4mm. Here are two pictures of the Resulting proportions in granular sizes.





All four soil types have been dried in the oven at 100C for several hours to remove any remaining traces of retained water.



A volume of 200ml was measured out from each soil and each batch was weighed.
Once everything was weighed another 200ml of water were added to each batch.



Everything was left standing for 60 minutes, and than the water was drained from each batch with a kitchen sieve in the order in which water was added to them. Finally all batches were weighed a second time, and the difference between the two measurements was calculated.

Measured Results

Akadama:
Dry: 140gr
Wet: 215gr
Diff: 75gr

Kiriyu:
Dry: 150gr
Wet: 200gr
Diff: 50gr

Kanuma:
Dry: 50gr
Wet: 140gr
Diff: 90gr

Seramis:
Dry: 75gr
Wet: 135gr
Diff: 60gr

Margin of error: +/- 5gr.

Additional Observations

The Akadama seemed to soak up the water immediately and none remained floating, while the Kiriyu still had some floating paritcles after an hour. Both the Kanuma and the Seramis had a substantial amount of floating particles throughout the hour the were left soaking. Stiring did not improve the situation.

Attached Images

	4Soils_02_Sifted_Kiriyu.jpg (47.0 KB, 273 views)
	4Soils_03_Sifted_Kanuma.jpg (48.5 KB, 272 views)
	4Soils_04_Measured_Soils.jpg (49.1 KB, 275 views)
	4Soils_05_Soaking_Soils.jpg (49.2 KB, 273 views)
	4Soils_01_Soiltypes.jpg (46.9 KB, 274 views)

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pootsie

Node:

Thank you for sharing this. Now I'm going to have to think about what it means.

pootsie

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p.s. My cat is a bonsaiTALK Master.
Columbus Bonsai Society

node

My Conclusions?

I am somewhat disappointed by the Seramis. I had expected it to retain more water than it did. I do find the light weight an advantage in larger pots. I am still convinced that a combo of Akadama and Seramis would provide a well draining soil with a long lifespan.

The fact that Seramis does not break up in the soil means that it will not provide any clayminerals, something that can be fixed by mixing with Akadama.

My main issue and something that I’ve never seen addressed here, is the simple fact that clayminerals provide important nutrients, and any high-fired clay-product will probably not provide them to the soil.

I think a 3:2:1 ratio of Akadama, Seramis, light peat or pinebark (organics) should provide a longlived and suitable soil for most plants. Mix in some lime to neutralize the PH if necessary.

Kiriyu is really not worth the trouble imho, it is expensive and has little added value exept for its color maybe. I’d replace the Kiriyu in you mix with a cheap gravel, and adjust the ratio of my mix a bit.

I did note that the Kanuma was much lighter than everything else, weighing a third of the Akadama and Kiriyu and only half of what the Seramis does at the same dry volume. It was terribly crumbly and soft though.

I had originally bought the Kanuma for a potted azalea of mine, but doubt that I’m going to use it, if it really breaks down as fast as it seems.

I think I’d mix Akadama and peat, or stretch the Kanuma with Akadama and Seramis to increase the lifespan of the mixture. My Azalea has been standing on Seramis and peat for a year, and is loving it.

All these mixtures are quite expensive, and I would like to have a light and fluffy mixture for those 30-40L training containers. Something in the direction of pottingsoil/peat and 1-2mm aquarium gravel. Maybe quite heavy, but cheap. Perlite seems not available here on retail.

A 20L pondbasket full of Akadama and Seramis is more expensive than most of the mallsai available in the average garden center here.
…

Stefan

__________________
Whenever you find that you are on the side of the majority, it is time to reform. - Mark Twain
Never let your sense of morals get in the way of doing what's right. - Isaak Asimov
The most savage controversies are those about matters as to which there is no good evidence either way. - Bertrand Russell

Joanie

Stefan, what clay minerals are you referring to, in the breakdown process? And isn't it easier to supply those minerals in another form, rather than through a process that causes the soil itself to become too fine and compact?

Joanie

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node

Clay minerals have the capacity to bind and exchange H+ ions, and as I understand it the clay content in soils has a rather significant effect on soil PH. Apparently sandy soils naturally have a lower ph requirement than loam/clay soils.

Also it seems that clay and organic material form a chemical complex that increases soil fertility. This complex forms a nutrient buffer in the soil and also buffers the hydrogen ions, stabilizing the soil PH and preventing souring of the soil.
My source also says that soils without this clay-organics complex can never be optimally fertile.

This is at the outer limits of my understanding though, maybe that someone that knows more about this can elaborate.

Stefan

__________________
Whenever you find that you are on the side of the majority, it is time to reform. - Mark Twain
Never let your sense of morals get in the way of doing what's right. - Isaak Asimov
The most savage controversies are those about matters as to which there is no good evidence either way. - Bertrand Russell

Joanie

That's wayyy over my head at this point.

So maybe others will chip in with explanations?

Joanie

__________________
"You can say any foolish thing to a dog, and the dog will give you a look that says,
'Wow, you're right! I never would've thought of that!'" ~ Dave Barry

onlyrey

Node, you could have done an article for the contest with this information; thanks very much, this is excellent

BrianBay9

Don't let me put words in your mouth Node, but it sounds like you're talking about CEC (cation exchange capacity). This is the ability for a soil component to temporarily hold on to nutrients, and slowly release them back. Generally a higher CEC means you have to fertilize less often. Clays (fired or unfired) have pretty good CEC, as I understand it.

Brian

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node

I believe CEC is part of this, but I don't think it is the whole of it. There seem to be some specific chemical processes between clay and organic materials that are not covered by CEC.

This is something I'm actually pretty interested about, because I've read about this relationship between clay and organics in several places, but there seems to be very little empirical evidence that it actually makes a whole lot of a difference compared to purely inorganic mixtures which seem to work fine for many people. Consider hydroponics even. Really what are the benefits of that hand of potting soil in your mix?

Stefan

__________________
Whenever you find that you are on the side of the majority, it is time to reform. - Mark Twain
Never let your sense of morals get in the way of doing what's right. - Isaak Asimov
The most savage controversies are those about matters as to which there is no good evidence either way. - Bertrand Russell