What the heck is Humus?

In my world of microbiology, when we talk about Humus there are two camps that jump up and shout their theories to the rafters.
The problem is that both camps are right, but they are talking apples and oranges (or mangos and walnuts if you prefer).
The problem is the accepted definition of Humus, which is:

Humus is dark, organic material that forms in soil when plant and animal matter decays.

When plants drop leaves, twigs, and other material to the ground, it piles up. This material is called leaf litter.
When animals die, their remains add to the litter. Over time, all this litter decomposes.
This means it decays, or breaks down, into its most basic chemical elements.
Many of these chemicals are important nutrients for the soil and organisms that depend on soil for life, such as plants.

The thick brown or black substance that remains after most of the organic litter has decomposed is called humus.
Earthworms often help mix humus with minerals in the soil.
Humus contains many useful nutrients for healthy soil.
One of the most important is nitrogen.
Nitrogen is a key nutrient for most plants.
Agriculture depends on nitrogen and other nutrients found in humus.

Some experts think humus makes soil more fertile.
Others say humus helps prevent disease in plants and food crops.
When humus is in soil, the soil will crumble.
Air and water move easily through the loose soil, and oxygen can reach the roots of plants.

Notice that Humus is described in this definition as "The thick brown or black substance that remains after most of the organic litter has decomposed".
Let's think about that description a bit. Thick brown or black substance, that is a very broad description that leaves out quite a lot.
Is this substance gooey? Is it dry and crumbly? Is it slippery when rubbed between the fingers or does it act more like superglue? What compounds and elements is the "substance" composed of?
The ambiguity of the definition does not meet the requirements of the microbiologist or the biologist or even the chemist, it appeals to lay persons simply because it is not a detailed description.

Let's try to get the whole picture of what exactly Humus is and more importantly to find out if it is something tangible, that we can create and use as an addition to soils.
We should probably start with what Humus is not.
Humus is not "organic matter" according to the definition it is what's left once the organic matter has decomposed.
And we know it isn't soil, again from the definition
So, now that we are thoroughly confused by the definition let's try to figure out what this "mystery substance" actually is.

Since the definition says it is what is left over from the processes of decay it must be comprised of chemical compounds some of which would fall into the "Organic Chemistry" compounds. (contain carbon in some shape)
We know that it comes from organic matter (leaves, twigs, bark fragments, manure left by animals, dead animals (protein, blood, cartilage, feathers, hair and everything else that makes up an animal body)
We also know that the organic matter has completely decomposed and leached into the soil leaving behind the mysterious "Humus" and that it is dark in color.
Now, when we look at something like a twig, it is made up of lots of cellulose and each cell contains proteins, water, minerals, oxygen, CO2 and that these comprise all the different parts of each cell that makes the structure we call a twig.
So Humus is what is left once all those items are gone. Hmm, that does make it a mystery, we just removed everything that makes a twig a twig by decomposing it and removing all or most of those organic compounds, but what would be left behind?
In the above definition they mention Nitrogen, but is it elemental nitrogen or is it some compound or several compounds that contain Nitrogen?
Then the definition adds further to the confusion by saying that even though it isn't organic matter, worms move it around in the soil and mix it with minerals.
The only way an earthworm could do that would be by consuming the humus. So  that means humus is something that can be digested by earth worms, or that it somehow is part of what the worms eat then they poop it out already mixed into minerals.
But, worm Castings are not Humus, they contain it, but they also contain other things.
We could further add to this confusion by bringing up "Humic Acids" but we will save that weird discussion for a future time.

So, Humus is made from organic matter, but it isn't organic matter because it is what is left behind the processes of decomposition.
It is dark in color (black or brown) and it isn't a liquid but apparently it isn't a solid either and it couldn't be a gas because it seeps into the soil as it is formed.

and now I have to teach my class, we will continue this discussion when I get back.

Redhawk

... and I will wait impatiently.

My friend says that humus is made by certain mycorrhizae and it acts like glue to hold microscopic bits of soil together. Is he right?

I've read that a vermi-compost can create humus, but that worm-created humus doesn't last as long as mycorrhizae-created humus. Was my source right? (no idea now *where* I read that)

Is humus like the common cold - many variations on a theme?

Please don't worry about answering the above questions directly, but if your lesson includes the answers, I'd greatly appreciate it.

And here I thought it was thick and tan-coloured chickpea paste that goes well with flatbreads.

-CK

hau Jay, sorry but your friend is wrong on the substance, but right on one of their functions.
Mycorrhizae create a substance that is glue like but it isn't humus, it is glomalin that the arbuscular mycorrhizae produce to stick particles of soil together and thus form soil structure for water and air infiltration.
Glomalin is a sticky glue­ like substance that is estimated to provide 30 to 40 percent of the carbon found in soils.

What you are reading is some of the misinformation that is out there.
Worms can not create humus,, neither can mycorrhizal fungi, both are part of the process but neither of them actually create humus.
Humus only comes in one form too.

Hope that helps.

Redhawk

(I decided to give you the answers now instead of making you wait for the second installment of this thread since you are kola.)

hau Chris,  Good one!

My understanding is that it contains humic and fulvic acids, and is the product of organic decay, thus containing carbon. However, it seems it is rather ill defined on a molecular level.  Interested to hear more.

It's the stuff that washes away right before the top soil does. :)

Bryant RedHawk wrote:
So Humus is what is left once all those items are gone. Hmm, that does make it a mystery, we just removed everything that makes a twig a twig by decomposing it and removing all or most of those organic compounds, but what would be left behind?

"What about the soul?" (This scene from Breaking Bad immediately jumped to mind when I read this!)

Last night a group of my friends went to the Blue Ball Inn for some after hours fun discussions (all professors from different disciplines)
Everyone was from the science department and we started talking about Humus.
Everyone had a different opinion, this is not surprising since we all agree it is more a mystery the deeper we get into studying it.  
3 chemistry professors said it was simply minerals held together by fungal glomalin (which they described as a short chain protein) and that was that.
The Organic professors agreed that it was minerals but they included proteins, double molecules of cellulose and all other nutrients the organic matter had held, bound up in the life form that was now decaying.
At that point one of the other Microbiology Professors said they thought that humus was more of an intangible substance or perhaps substances (this professor is doing a post doctorate with humus as his subject)
and while he had to agree with all that had been said, there were strong indications that it was also dependent upon the microbes that create the substance staying "on board" as it (humus) sank into the subsurface soil.
He went on to say "the problem seems to be the many differing ideas of what humus is as well as what it does, bringing up that not near enough study of humus has been done from the view of what it does since most of the research to date
has been on what humus is and how it comes into existence. As he finished everyone looked at me and asked "what does our genius think?", now this really shocked me, everyone there could fit that "genius" moniker, in truth I don't see me fitting it, but they all say I am far to modest.
(since I was around 10, many of my teachers expected me to have the highest grades of what ever school I was enrolled in, this was apparently because of some battery of "IQ" tests the school had given to all students.)

Everyone at our table was staring at me, waiting for my answer. (want to experience nervousness? have such a group of people stare at you while "out with the "boys"").
It took me so long to gather my answer that another round showed up and was finished off before I spoke.

"Humus, I began, is one of those substances I term a mystery, so much wrong information has been published in every form that one has to first identify and toss out the garbage just to begin.
It is defined in ambiguous terminology as if the dictionary writers haven't got any inkling of what they are defining, but want to appear that they know what it is they are defining.
For me, Humus is the result of total decay, bacteria, fungi, amoeba, flagellates, nematodes, worms, and every other micro and macro organism that feeds on dead organic matter is involved in creating what we term humus, it makes it that mystery substance.
We can identify every bit of matter that makes up humus, we can identify the critters that do the work of making humus, but since it almost immediately disappears into the soil matrix, holding on to a handful of the stuff is quite difficult to do.
There are commercial products that claim to be humus but when we open the packaging that holds their product, we find compost, not humus only.
While there is probably some humus in that bag or box of "humus" everything in that container is not really humus it is mostly a carrier, such as compost.
Humus is very close to the substance or substances that allowed life to take hold on this planet. It is kin to that "Primordial soup" that the first bacteria sprang from, that is how much a  mystery humus is.
It consists of all the molecules and atoms that were part of the organic matter that was decayed to the point of not being even compost.
That means that it is comprised of minerals, proteins, carbohydrates, sugars and starches, all freed by decaying micro organisms then further refined by those organisms along with the worms and other macro organisms.
The bacteria tend to remain in and around the newly created humus, which makes it a compound containing more than just substances.
Humus also seems to be a solid liquid since compost can release some of it as a leachate but we are also supposed to be able to hold it in our hands, which I've personally never been able to accomplish. "

The professor (timothy is his name) doing the Post Doctorate on humus clapped (he might have been sitting next to cooter by this time) his hands and loudly said I had a grasp.
At this point in the evening, it was evident that further discussions would be strongly influenced by alcohol so I excused myself and headed home.

So, at this point in our exploration of what the heck humus is, we seem to have more of what it isn't than we do of what it is.
The question of is it solid or liquid is still out there for absolute discovery, but we can look at it as both and not be in error.

My ideal way of describing humus would have to be: The solids and liquids formed by the complete digestion of any organic matter by a microbiome which is then further processed by macro organisms found in soil.
It is comprised of every element and compound previously contained in those dead organisms (plant and animal) that pile up and then go through complete decay ending up as digested waste from those organisms that process such matter.

Humic Acid is a substance we can find through scientific chemical testing but if you want to find it lurking under or around a compost heap, you will have little success since it almost instantly converts minerals into salts that are able to be used by any plant life.
Humic Acid life is fleeting, which is why you can't go to any nursery store and buy some. Humic Acid does, however, form as water seeps slowly through a finishing compost heap.
We can see the results of such a leachate forming if we move the finished compost heap and study the top 6 inches of soil that was underneath the compost heap as it decayed into finished compost.
The crumbly texture of that soil is the giveaway that humic acid has been there. In that same soil we can, under a microscope of 2500 power, with polarization, see  particles of humus on a prepared slide but to see what makes up those humus particles we need the electron microscope.
It is easier to discover what makes up those particles of humus by chemical testing both inorganic and organic.
Are these substances really good for soil and all the life forms that grow and live in soil? you betcha, both are keystone substances in that respect.  

Let me know if you want me to go deeper into this rabbit hole, if you, the reader do desire more understanding, I'll continue.
(This thread is also the subject material of my class, so I have around 10 hours of material I can divulge if there is that sort of interest)

Redhawk

hau Diane, Indeed, but that would take us towards "religion, or beliefs" and that stuff belongs in a different forum.
If you want to discuss your question pm works for me.

Redhawk

Bryant RedHawk wrote:hau Diane, Indeed, but that would take us towards "religion, or beliefs" and that stuff belongs in a different forum.
If you want to discuss your question pm works for me.

Redhawk

Yeah, I meant it kind of as a joke. Of course, Walter White answers: "There's nothing but chemistry here." And irony, too, to pun a bit! ;)

Dr. Redhawk wrote:

Glomalin is a sticky glue­ like substance that is estimated to provide 30 to 40 percent of the carbon found in soils.
And later wrote: That means that it (humus) is comprised of minerals, proteins, carbohydrates, sugars and starches, all freed by decaying micro organisms then further refined by those organisms along with the worms and other macro organisms.

So how much carbon does the humus hold?
Are the humus and the glomalin equally important in the soil?
I think I know a little about how to encourage the glomalin level in the soil (don't disturb it much, grow trees and shrubs that encourage fungi, don't add anything nasty to your soil like artificial fertilizers or pesticides, spread native fungi and worms around because they spread and support the things that make glomalin - are any of these wrong?)
I've heard people say that the way to make humus is to compost "just right" which I've never got the right ingredients at the right time to do. I think that making leaf mold is also supposed to be a way, and I did see a post on permies about that recently. Most of my leaves are really big and just seem to mat down and take years to decompose. Maybe that's the point?

Yes, please continue. I know that healthy soil is *very* important for sequestering carbon. I want to do what I can to speed that process within my abilities on my land. (Not that I won't also just plant trees, because that sequesters carbon on at least a short term basis, but I live surrounded by 150 ft cedars and fir trees and the cedars are looking increasingly unhappy with the climate changes that are happening.)

Bryant RedHawk wrote:
Humic Acid life is fleeting, which is why you can't go to any nursery store and buy some.

You can buy some stuff in a box that's labeled humic acid.  What's that stuff?

With trees, alas, the individuals will either be able to survive the changes, or not. I will try to find the article to link, but there was one recently about an ancient sugar maple here in Canada known as the "Comfort Maple," after the family whose land it lives on, where they're air-layering branches in order to get cloned seedlings to plant out, to get more of the ancient (we're talking in the neighbourhood of 500 years old) DNA out there.

My question riffs a bit on your comments, Jay. I am wondering if I am right in my idea that there's more humus in deciduous systems than coniferous ones. If so, and if humus is a soil-building, carbon-sequestering silver bullet, should we be, perhaps, at least interplanting more deciduous trees? I mean, more leaf litter, more humus, right?

I was also wondering if there's a temperate range that's optimal for humus creation and, well, lifespan, I suppose might be the best term. I would guess, based on what is known of tropical and non-temperate soil activity, that constant and vigourous biological activity can "burn out" these soils, for which we look to the example of terra preta. Does this mean that those conditions are left with only humus, as it was stated that humus is what is left after most or all biological breakdown was accomplished? Or is it consumed by something in the end? Is it lost if it is carried down through the soil column? Oh, and if you use ammonia or urine to speed leaf decomposition, is that speeding them on the path towards humusville, or is it obviating that possibility?

I guess I have a few questions, then. I will probably have a few more later. Give me a bit.

Oh, and thanks again, kola Redhawk, for this and all the great work you do to help us develop our foundational understanding of what it is we're seeking to do.

-CK

Elizabeth Geller wrote:

Bryant RedHawk wrote:
Humic Acid life is fleeting, which is why you can't go to any nursery store and buy some.

You can buy some stuff in a box that's labeled humic acid.  What's that stuff?

I would not know what anyone selling "Humic Acid" is actually marketing.

My degree *mumble, mumble*odd decades ago was in Agronomy.  We learned about the physical and chemical properties of soils, but mostly nuttin' about its biology.  Since discovering Michael Pollan and Joel Salatin, I've been reading like mad to catch up.  This thread suits me down to the ground, as one might pun.

I came across the term "humin" in 'The Soils Will Save Us' by Kristin Ohlson, and have been high on it ever since.

She defines it as 'Nonextractable Soil Organic Matter' and the mechanism for long-term carbon sequestration.

One of the scientists she references - David C. Johnson New Mexico State University soil biologist found that the biological balance of bacteria and fungi in composts is much more important than the chemical components in their effectiveness.

I want to learn more.  Teach away!

Bryant RedHawk wrote:

Let me know if you want me to go deeper into this rabbit hole, if you, the reader do desire more understanding, I'll continue.
(This thread is also the subject material of my class, so I have around 10 hours of material I can divulge if there is that sort of interest)

Redhawk

Yes please!! I love this kind of information. Sometimes I have dreams at night about gardening, plants and soil, and I gobble up this kind of stuff.

Bryant RedHawk wrote:
I would not know what anyone selling "Humic Acid" is actually marketing.

Perhaps similar to a bottle of "oxygen supplement" I found in my mom's pharmacopeia after she died.

Redhawk=
Your posts are medicine for the Earth. I aim to dose that medicine, starting with my yard.  Please bring it on.
John S
PDX OR

Jay Angler wrote:Dr. Redhawk wrote:

Glomalin is a sticky glue­ like substance that is estimated to provide 30 to 40 percent of the carbon found in soils.
And later wrote: That means that it (humus) is comprised of minerals, proteins, carbohydrates, sugars and starches, all freed by decaying micro organisms then further refined by those organisms along with the worms and other macro organisms.

So how much carbon does the humus hold?
Are the humus and the glomalin equally important in the soil?
I think I know a little about how to encourage the glomalin level in the soil (don't disturb it much, grow trees and shrubs that encourage fungi, don't add anything nasty to your soil like artificial fertilizers or pesticides, spread native fungi and worms around because they spread and support the things that make glomalin - are any of these wrong?)
I've heard people say that the way to make humus is to compost "just right" which I've never got the right ingredients at the right time to do. I think that making leaf mold is also supposed to be a way, and I did see a post on permies about that recently. Most of my leaves are really big and just seem to mat down and take years to decompose. Maybe that's the point?

Yes, please continue. I know that healthy soil is *very* important for sequestering carbon. I want to do what I can to speed that process within my abilities on my land. (Not that I won't also just plant trees, because that sequesters carbon on at least a short term basis, but I live surrounded by 150 ft cedars and fir trees and the cedars are looking increasingly unhappy with the climate changes that are happening.)

Humus is about 40% carbon, so if you could weigh the humus you could calculate the carbon. This works in the lab but it might be extremely difficult to do a field test since the humus tends to migrate into the soil as soon as it has formed.

Jay, you have it right, lots of mycorrhizae = lots of glomalin.  "Just Right" sounds to me like a pipe dream, what exactly do they mean by "Just Right"? most likely no one knows.

Healthy soil is so important that without it the green of this planet would die.  
If your cedars (true cedars? not junipers being called cedars) are looking unhappy, you should check the soil pH first, you want to know what the pH is at the trunk, and then every foot away from the trunk out to 4 feet beyond the tree's drip line.
Once you know those figures, it might be easier to figure out what is wrong.

Leaf mold doesn't break down into humus, if it did there wouldn't be any leaf mold left, in fact there would be almost nothing left except for really dark, crumbly soil.

Ok, Jay, and  James, I will continue this thread.

Redhawk

Ruth Meyers wrote:

Bryant RedHawk wrote:
I would not know what anyone selling "Humic Acid" is actually marketing.

Perhaps similar to a bottle of "oxygen supplement" I found in my mom's pharmacopeia after she died.

Very well could be, like the canned air I've seen in novelty stores.  
I managed to collect some humic acid in the lab, once, it was an almost black rather gooey substance, I managed to collect 3 ml of it from 100 kilos of compostables (starting weight).
By the way, the humic acid lasted for a week in the test tube because it was kept in a fridge when none was being extracted for testing.
Humic acid is very much "stuff of life" material, free carbon (which if you add water turns instantly into carbolic acid and many proteins drop out as a floculant).

Redhawk

I am taking in Bryant's words and learning.  

So if I understand your explanation, your saying that humus is what remains at a certain, rather short, point near the absolute end of the decomposition process.

If that's true, there may be a fair amount of variation between different batches of humus, depending on the original materials, agents of breakdown, and temp and moisture conditions.  For example, the end result of a pile of straw or a pile of seaweed with a few dead fish,  although there would also be some real common ground also.

Maybe part of the problem is that humus seems to be a poorly defined "blanket word", like trash or junk, (which actually reveals more about the speaker opinion of the subject than the subject of discussion).  Science strives for precision and exactness, while the english language is pretty sloppy in many ways.  I expect most languages are.  Precise in the things that matter most to them and sloppier as it moves away from their focus (i.e. Inuit and its many different words for specific kinds of snow).

Mysterious, Magical, Molecular, Poo

I am fascinated. Please continue.  Thank You for sharing your self and your knowledge Dr. Redhawk. You are very generous, indeed.   k

Ruth Meyers wrote:My degree *mumble, mumble*odd decades ago was in Agronomy.  We learned about the physical and chemical properties of soils, but mostly nuttin' about its biology.  Since discovering Michael Pollan and Joel Salatin, I've been reading like mad to catch up.  This thread suits me down to the ground, as one might pun.

I came across the term "humin" in 'The Soils Will Save Us' by Kristin Ohlson, and have been high on it ever since.

She defines it as 'Nonextractable Soil Organic Matter' and the mechanism for long-term carbon sequestration.

One of the scientists she references - David C. Johnson New Mexico State University soil biologist found that the biological balance of bacteria and fungi in composts is much more important than the chemical components in their effectiveness.

I want to learn more.  Teach away!

OK, I love Kristin Ohlson's definition because it really fits the humus conundrum.  
David is right on the money.
It was finding out that there is a definite balance of the Microbiome organisms that creates the best compost that got me looking into humus and humic acid since they are the end products of a super good compost heap.

Ruth Meyers wrote:I came across the term "humin" in 'The Soils Will Save Us' by Kristin Ohlson, and have been high on it ever since.

Serendipity. Right before coming here, I picked up the Kindle edition of this book on sale for 1.99. So if anybody doesn't already have it, here it is: https://amzn.to/2OYq3sy

Mick Fisch wrote:I am taking in Bryant's words and learning.  

So if I understand your explanation, your saying that humus is what remains at a certain, rather short, point near the absolute end of the decomposition process.

If that's true, there may be a fair amount of variation between different batches of humus, depending on the original materials, agents of breakdown, and temp and moisture conditions.  For example, the end result of a pile of straw or a pile of seaweed with a few dead fish,  although there would also be some real common ground also.

Maybe part of the problem is that humus seems to be a poorly defined "blanket word", like trash or junk, (which actually reveals more about the speaker opinion of the subject than the subject of discussion).  Science strives for precision and exactness, while the english language is pretty sloppy in many ways.  I expect most languages are.  Precise in the things that matter most to them and sloppier as it moves away from their focus (i.e. Inuit and its many different words for specific kinds of snow).

Right now, we think that if you build a compost heap with animals included as one of the "ingredients" at the end of decomposition all that would be left (perfect world) would be humus and the pile you built would be at soil level, no hump of stuff or mound of stuff left.
Variation would be dependent upon what materials were included in the heap. Humus seems to require some animal parts be one of those materials. (we don't know for sure yet, but we are working on it)

English is not a perfect language but it is the one used, however it can be very precise (lawyers are also very precise in their use of language and they use English as the primary language for law).

I think the main problem with the word humus is that many people use it to describe many different things that are not humus.  
I've seen humus used to describe finished compost, yet humus will not be found in finished compost, it will have already moved down into the soil matrix and disappeared between the soil particles.
I've opened bags of "Humus" only to find partially finished compost.

Redhawk

Bryant RedHawk wrote:
I would not know what anyone selling "Humic Acid" is actually marketing.

Here's the description from the Down to Earth brand:  Down To Earth™ Granular Humic Acids is a highly concentrated source of humic substances that is ideal for use on fields, turf and vegetable gardens. Carefully mined from one of the world’s richest deposits, DTE™ Granular Humic Acids is derived from the ancient remains of decomposed organic plant materials. Naturally occurring, unaltered oxidized lignite, DTE™ Granular Humic Acids are crushed, screened and graded to a particle size of 1-3mm."

I have no idea what any of that actually means, but there you go.

I seem to remember from my geology classes (back when Noah was just a cabin boy) that lignite deposits were described as pre-coal, meaning layers of organic matter that were not raw vegetation by any means, but had not been subjected to enough heat and pressure to convert them to coal.  I seem to recall that there were huge deposits in Russia around Moscow that were (arm waving estimate here) a couple hundred million years old.  Our professor discussed them as a fuel source.  Not as many BTUs as coal, way better than peat.  

No idea if it would still retain humid acids.

I used to think that humus was really nutrient rich organic matter that had no distinguishable plant or animal parts in it. Now it sounds like it's bare nutrients that haven't yet been taken up or secured by soil life.

Elizabeth Geller wrote:

Bryant RedHawk wrote:
I would not know what anyone selling "Humic Acid" is actually marketing.

Here's the description from the Down to Earth brand:  Down To Earth™ Granular Humic Acids is a highly concentrated source of humic substances that is ideal for use on fields, turf and vegetable gardens. Carefully mined from one of the world’s richest deposits, DTE™ Granular Humic Acids is derived from the ancient remains of decomposed organic plant materials. Naturally occurring, unaltered oxidized lignite, DTE™ Granular Humic Acids are crushed, screened and graded to a particle size of 1-3mm."

I have no idea what any of that actually means, but there you go.

OK, so they are spreading misinformation out of the greed factor yes? humic substances would be very um, controversial in the biology/ microbiology world as well as in the Agronomy world. Notice they think there are deposits of something that has been found to infiltrate soil so well that you can't separate it from the soil particles. Then they say "ancient remains of decomposed organic plant materials" which does not fit any definition of humus or humic acid. Then they admit that they are selling ground up lignite not humus or humic anything.

So, I am going to call BUNK! on them. You will not ever find any "ancient" humus, it is impossible to do since it incorporates so completely with soil that you can't separate it and it would have been used up by plants anyway.

Redhawk  (PS, what that means is that they are selling you a "bill of goods" not selling real humus or humic acid)

Huxley Harter wrote:I used to think that humus was really nutrient rich organic matter that had no distinguishable plant or animal parts in it. Now it sounds like it's bare nutrients that haven't yet been taken up or secured by soil life.

Humus is organic material that has undergone complete decomposition, so complete that nothing of the original materials is distinguishable even under a microscope.
It is not "bare nutreints that haven't yet been taken up", it is a nutrient matrix that melds into the soil beneath. More specifically it is a nutrient matrix being re-used by new plants (circle of life).

Humus is how nature recycles plant and animal parts that have died and then fed the trillions of bacteria, fungi and all the other microorganisms of soil.
The nutrients could perhaps be construed as bare but they have been used to build plant parts and animal parts that are alive then died and are being recycled yet again.
However, grabbing a hand full is almost impossible since as it forms it melds into the soil it touches, virtually disappearing almost as soon as it forms.
Humic acid is even more fleeting in separate existence since it is liquid it seeps into the soil where it binds to particles of soil as soon as it touches them and this is such a complete binding you can't locate it except through chemical testing.

Awesome information Redhawk. I also thought humid acids were a tangible shelf stable thing. Can you please explain fulvic acids, what they are and are they formed by or related to decomposition in any way like humus and humic acids?

Fulvic acids are acids which are created by the breakdown of rock minerals and remain soluble.

Humic acids are created by leaching rain water through the humus in a compost heap, it appears to go away quickly because it will bind with other organic materials or dirt particles almost as quickly as the humic acid forms and so don't remain soluble.

Redhawk

Bryant Redhawk wrote:

Humus seems to require some animal parts be one of those materials. (we don't know for sure yet, but we are working on it)

That is good to read even if not sure yet. I make a point of digging a hole in my working compost heaps and adding high carbon material with whatever bird I've lost, or the remains when harvesting, and then cover it over. I figure I've done it right if there is no 'dead animal' smell over the next few days. I always considered it the responsible way to let the animal continue on in the cycle of life. If it's increasing the odds of my pile adding humus to the planet, that's a happy thing.

Rock on Jay, yep if there isn't a decay smell coming from the heap with added animals, you are in great shape. (get some plastic and sneak it under the heap around the edges at about week 3, any dark brownish liquid that comes out, that is humus in the raw form my friend)

Bryant RedHawk wrote:

Elizabeth Geller wrote:

Bryant RedHawk wrote:
Humic Acid life is fleeting, which is why you can't go to any nursery store and buy some.

You can buy some stuff in a box that's labeled humic acid.  What's that stuff?

I would not know what anyone selling "Humic Acid" is actually marketing.

che
According to John Kempf of advancing eco agriculture (an eco ag input manufacturer and ecological farm consultant), the 'humic acid' (dark brown liquid that stains just about anything it touches brown/black and is labeled as some %humic acid) is made by taking super high humus soil, usually from ancient dry lake beds, and agitating it in a tank for several day with a very strong acid (he said pH of 2 or 3). Then the liquid is siphoned off and packaged (maybe diluted first?). He said the remaining solids are then agitated for another day or two with an extremely basic substance (pH 12 or so) and that liquid is siphoned off and packaged as '0.6% humic acid' and sold to customers as fulvic acid and has a light golden color. He said that the remaining solids in the tank is almost entirely humin, which seems to be the source of humus' stability in the soil.

I really appreciate your input on this subject dr. Redhawk and I'd like to offer up an aspect of my understanding of humus and hear your thoughts. I understand soil humus as a dynamic matrix of mineral ion colloids 'passing' through a mosaic of biology. It is such a valuable soil component because it constrains leeching by 'holding' the minerals (including nitrogen and other notorious 'mobile' elements) within the living biotic web. It also keeps these minerals completely accessible to plants through this same process, it's not rock dust molecules that require biological action to deliver to plants, it's those available forms of the myriad minerals suspended within the cycle of bodies/excrements of microbes.

Also, I've been reading a book called Humusphere by Herwig Pommersche, written in 2014 or so and just recently translated from the German to English. It doesn't delve as deep into the 'what' of humus as I had hoped be how raises some interesting theories of the 'how' and generally poses a compelling theory to undergird sustainable agriculture

To repeat, Fulvic acids are rock mineral acids not organic acids. On that one point John Kempf is not correctly representing at least one of his companies products, according to your post S. Lowe.

As I have said many times, there is a lot of misinformation out there that is being believed which makes getting the correct information out there harder than it should be.

The single largest problem with humus (and humic acid) is all the misinformation that is in circulation and part of that is calling things that are not humus or humic acid, humus or humic acids.
Organic matter in the soil is often called humus, but it is far closer to being compost rather than humus.
Many people are now selling organic materials and calling these materials humus, but what they are selling is more like compost.
This misidentification continues because "experts" continue to use the wrong terminology when they are talking about soils and how to improve those soils.

Humus is not something you can work into the soil, the very nature of humus is that of complete and total decay of organic matter, humus occurs only at the molecular level, so our eyes can't even detect it.
Humus, being molecular in nature means you would be hard pressed to hold any of the stuff in your hands since to find it you first have to locate organic matter that has been completely decayed, solid matter can not be humus because we can grab a hand full.
Compost is solid matter that is going through the process of decay, it is useable by humans because it has not finished the decay processes, once it does then it will be out of our sight and touch.
Humus can not come from coal because coal is plant material that became compost like and was then put under high pressure, which causes heating, and that turns it into coal eventually.
To think you could take coal and grind it up and get humus from that ground up material is showing lack of understanding what humus is.
Coal doesn't decay, if it did we would not be able to mine it and burn it as a fuel.
The deeper you look at everything represented as humus, the more you find that what ever is being called humus is most likely not humus but some form of organic matter.
Humus has been decomposed so much that it actually is no longer organic matter, it came from organic matter but since it has been broken down into molecules or atoms, it is no longer organic matter.
If you were to call humus "derived from organic matter" you would be closer to it's true identity.  

Plants and animals contain many of the same minerals and other nutrients (Like N,P,K as an example) we use most of those minerals and nutrients to build the cells and other stuff that make our bodies and fuel them.
Humus would be those minute pieces (minerals and nutrients) in the same forms that plant roots or animal digestive tracts take in so the organism will survive and grow or maintain the current structure.
Humus doesn't actually add "organic matter" to the soil, this is one of those misconceptions that has been bandied about for so long that many people say it as a fact, but it isn't. (sort of along the Urban legend type thing)

Humic acid is another item that has many misconceptions running around about it.
Humic acid doesn't stay humic acid, it gives up electrons quickly to become stable, but in doing this it no longer is an acid it becomes another molecule floating in the soil.
Humic acid is formed by rain water passing through humus, it takes on electrons from the humus molecules thus changing those molecules the water robs the electrons from.
Like Humus, Humic acid reacts rapidly once formed so it is here then not here, snap your fingers and you can get an idea of how long humic acid exists as humic acid.
It is the rapidity of change in these two substances that have made it so hard to study or even investigate, only recently have we come up with the right tools to be able to do proper study of the properties of these two keystone items of the soil.
(keystone items or beings are those that are so critical to the well being of the planet or ecosystem (soil is an ecosystem) that without them, the whole system falls apart).

Humans have a need to quantify everything which is probably one of the reasons there is so much wrong info floating around the different media, we have an innate need to be able to describe everything, it is what allows us to understand anything.
If we don't know the real facts of how something works we will either experiment to gain knowledge about that which we don't understand or we will invent what appears to be knowledge.
It is these human traits that push us forward in the quest for knowledge but these traits are also what lead us to make stuff up so we sound like we are knowledgeable.

If you want to find humus you have to look for it in a laboratory setting since out in nature it disappears almost as quickly as it forms.
This is because it can't exist until the organic matter that creates it has to be completely taken apart by the processes of decomposition, only then can humus come into being.
So as the last bits of say a tree limb that has a dead lizard gripping it disintegrate into those components that made up the solid parts of the limb, you see humus be created.
Once humus is created, it immediately binds with those molecules and atoms that make up the inorganic parts of soil at that instant, humus is gone.
We now have instruments that allow us to locate where the humus went and what it turned into and those instruments identify these substances as organic because they will contain the carbon atoms that were freed when the tree limb decayed away from the actions of bacteria and fungi.
This is why humus is such a mystery, it is still almost impossible to take any sample of soil and locate that substance known as humus (or humic acid since both seem to work in similar fashion).
However, if humus didn't exist, ever, then we would not have rich soil to grow plants in and those plants that did sprout would be lacking much of what makes them up.

Experiments have been done that were designed to locate, isolate and congeal into a solid, measurable form, the ions, minerals and elements that make up humus.
Most of these experiments have either failed from their design or the substance was found then it changed molecularly enough to not be the desired form humus any longer.
This is the type of investigation that creates bald scientists, they most likely pulled all their hair out from frustration.

Redhawk

Bryant, thank you for this excellent thread.

Since it's so difficult to define what humus is because it's taken up by the plants and soil life, then couldn't it be defined by the molecules and compounds taken up by plants and soil life? Now that I write it, this sounds sort of redundant, but if we know more about what plants take up in their roots than we do about humus, then it might be possible to begin defining it from both sides since humus = food.

It's been so long since I took college horticulture that I don't remember how much was known about plant requirements except that it was pretty basic (e.g. N, P, K, salts). I hope much more is known now.

Hau Robin, indeed we do know more now than we did when I started college in 1967. We know more today than we knew in 2000 and by the middle of 2020 we should have at least doubled our knowledge from 2000.
With so many people scrambling because of the global warming freak out, new studies are being published every month now when before it might have been every 6 months to a year between same subject papers.

Humus may or may not be considered food for microbiome and plants, that is one of the big questions right now.
We know for instance that humus will have many minerals and other nutrients but we don't know if these end up in plant roots without any middle men playing a role.
I suspect that the humus materials feed more microorganisms than it does plant life, but the experiments are still running so no solid data at this date, hopefully before Christmas we will have solid data and some conclusions.
We just have to wait and see how things develop (I helped design some of the experiments but I am not running the study), this study has involved more researchers than most of the work I done.

We also have around 20 masters students doing a lot of the "grunt" work, so it's a fun, exciting time.

Redhawk

When I get home (my farm) I'm going to do some changes to methodology being used.