What the heck is Humus?

Bacteria do not attack lignin, so any woody parts in leaf mold will remain intact until fungi locate that food source. The veins of leaves are made up of lignin, the broad spaces between those veins don't contain much if any lignin.

Acidity of leaf mold is actually dependent upon which types of leaves are used to make it. Most leaves will contain tannins, which are acidic as are pine and other conifer leaves (needles).
That means that we should expect leaf mold to be at least somewhat acidic but most plants like slightly acidic soil as do most of the members of the soil microbiome.

The best success I've had at clay conversion has been with straw bale gardening, the leachates from the bales includes lots of carbon both free and in compound forms and these leachates help change the fine clay particles into clumps of fine clay particles which then adds more carbon and other organic molecules to the clay so that it will be able to convert to soil through the activities of the bacteria and fungi. Fungi serve to form conglomerates of soil particles, including the superfine clay particles, which then opens the structure so that water can seep down through instead of sitting on top.

We have a type of red clay that is great for making earthen ware, where we have been using straw bales for growing the soil beneath is now nice and friable, soaking up water like a dry sponge and it is full of microbes.

Redhawk

First, Chris, I also have heavy clay, but have greatly improved it within a couple of years in my vegetable garden, by creating raised beds with lots of organic matter, and periodically adding more, AND SAND. Some claim adding sand to clay creates bricks, but in my experience it helps greatly. They key I think maybe, is to always add organic matter as well. I've also read that you should use coarse, not fine sand. I do have an area I had planned to turn into a shade bed that I have that "maybe not in my lifetime" thought about, but that's because it's not only extremely heavy clay but also next to the house, and I figure I disturbed enough tree roots for the support piers for the house and the water line, that I'm not willing to rototill in there. I just dump a foot of whole leaves in there every year.
But--Bryant and Chris--thing is, I don't think I can get by with no tillage, not with clay soil. The leaf mold AND compost get worked into the soil once a year, using a shovel, along with sand sometimes. I only use chopped leaves as mulch in my flowerbed, and not the dense leafmold that gets worked into my garden beds. I think it was Elliot Coleman who said leafmold should be composted separately because it's a different process, and also that carrots and brassicas particularly benefit from it while peppers should not have it, so I follow that tho I'm not sure it's true.
I think it was Teaming With Microbes that said compost made from woody debris is mostly fungal while compost made from forbs and manure and food scraps is bacterial, and most annual plants prefer the bacterial compost while trees like the fungal. But my experience said my young fruit trees liked manure just fine, and the garden beds that got leafmold have generally done better than the ones that got compost or (rarely) manure.
It was because of the difference between fungal and bacterial dominated compost that I thought maybe grass clippings, and perhaps urine, didn't belong in my leaf bins.
Thanks for your prompt response!

Bryant Redhawk wrote:

Humic materials do wonderous things to the soil, they open structure, they provide nutrient flow, water infiltration, bioactivity increases too. The free carbon becomes part of the matrix so it is captured and that also is good for the microbiome we want to feed.
Humus also will open clay structures (clay will eventually look more like terra preta with enough humus added over a long period of time).

My bold - I have an area where previous owners dumped a lot of clay subsoil which resulted in compaction and great difficulty growing conditions. I've already been making windrows of "compost" (chipped and shredded tree duff + veggie scraps + duck/chicken shit +dead animals + okara when a friend collects more than he can sell) but I admit the piles get added to as material is available rather than a "built compost", and there's no way I've got shovel-able soil in that area to "cover" the pile, so I use a tarp.

So my question are -1. How long would "eventually" be? (decades or millenials?)
2. Would it work to shift most of what's left of the pile to a new spot to add more fresh materials to what hasn't degraded (tree duff takes a long time) and plant anything known for tap roots (I'm thinking dandelion and diakon +) for at least a season, and then build the pile again so we get root action as well as compost action working on the clay?

This area has some of the worst soil, but the most sunshine which is a limiting growth factor for me - improving the area short of several loads of top soil has been frustrating me. Is it that bad a situation, or am I doing it wrong?

hau Mary, there is nothing wrong with working organic matter into your soil (that is not what I consider tillage that is soil amendment, you are adding organisms with that organic matter).

Plants are wonderful creatures, if we give them organisms they don't want, they send out signals to move those critters away from their roots, they can also call to their roots those organisms they prefer. (plants can even adjust pH around their roots)

Leaf mold isn't actually composted since composting involves not only bacteria but also fungi, insects, worms, and a huge number of other microorganisms which decompose the compostable ingredients more completely than would occur in leaf mold. (at least that is how I look at the differences)

As I have mentioned in my soil series, we human organisms would do well to offer our plants a very diverse set of microbes and let the plants pick and choose those they want around them.

(almost all plants benefit from mycorrhizae around their roots, inside their root cells and extending out to the fungal network that all good soils contain. That precludes the idea that bacteria loving plants don't want or need fungi in the soil, the main group I've found that don't want much fungi around are cactus family members.)

Redhawk

Jay Angler wrote: I have an area where previous owners dumped a lot of clay subsoil which resulted in compaction and great difficulty growing conditions. I've already been making windrows of "compost" (chipped and shredded tree duff + veggie scraps + duck/chicken shit +dead animals + okara when a friend collects more than he can sell) but I admit the piles get added to as material is available rather than a "built compost", and there's no way I've got shovel-able soil in that area to "cover" the pile, so I use a tarp.

So my question are -1. How long would "eventually" be? (decades or millenials?)
2. Would it work to shift most of what's left of the pile to a new spot to add more fresh materials to what hasn't degraded (tree duff takes a long time) and plant anything known for tap roots (I'm thinking dandelion and diakon +) for at least a season, and then build the pile again so we get root action as well as compost action working on the clay?

This area has some of the worst soil, but the most sunshine which is a limiting growth factor for me - improving the area short of several loads of top soil has been frustrating me. Is it that bad a situation, or am I doing it wrong?

Do you know what type of soil is under that "dumped subsoil"? I hope there is something down there that resembles top soil or better.
It sounds to me like you are on the right path, speeding up the process would involve use of compost teas and fungal slurries, preferably poured over and through the windrows, that will do two things for you. 1. it will speed up the breakdown of your compost materials and 2 it will create humus forming opportunities that without the additions would take at least 4 years to accomplish. (eventually (when I use it in this context) generally means at least 5 years and up to 20 years, so it is a broad time line, dependent upon how  much you are adding and how frequently you are adding).a
One other option you have is to use straw bales on top of your compost windrow, these could be whole bales or cut loose and spread over the top like a thatch roof sort of thing, then you would add your slurries and teas over the straw so the liquid flows down into and through to the soil beneath, which will deposit around 1 inch depth of soil per breakdown of the windrow materials, which will go along faster because of the microbiota you are adding. I have changed one beds soil from 3 feet of red clay to 1.5 feet deep good, dark soil over 1.5 feet of red clay that is left at this point. (three years from start up to now)

Redhawk

≥I haven't read through this whole thread yet, but from your amazing analysis given to your professor buddies, I believe I may have the definitive definition of humus: humus is, in the alchemical sense, the quintessential poop. The poop of the poop of the poop.....(five times)  broken down to its liquid and solid components and its molecular and atomic aspects; perhaps we can even say the essence of matter itself which includes the ineffable non-thing that is life itself. Now I'll get back to reading. Just wanted to throw that in the hat. Thanks so much for this and yes, please, continue this discussion. I'm loving it.

Bryant RedHawk wrote:I can almost guarantee that the end of this thread will cause head scratching at the least.

LOL, RedHawk, you have done an amazing job of hanging in there with everyone's questions and opinions. I confess that I was extremely puzzled at first, because it seemed to be easier to say what humus isn't than what it is. But gradually, I began to see it as a state of being rather than an object of itself. That's probably not quite it, but for now, it's a start for me.

The burning question for me was how to get more of it into the soil. But you've answered that too.

Bryant RedHawk wrote:To me the only thing we need to know is that when we place a good sized compost heap directly on the soil surface and let the microbiome do what it loves to do, we end up with a soil that has properties we can not simply go locate out in nature unless we happen to sample the exact right spot.  

It is good to know about the necessity of animal remains, too. We've always buried that either in the compost or directly in the garden or pasture.

Thank you for an informative and interesting discussion.

I know I was being silly in my previous post. In fact, as I was reading RedHawk's exposition I was transported into the soil where the macro-creatures were eating/digesting all the rich organic material, then others would further eat/digest their waste, and the micro-creatures would all do the same.......and on and on until what was left, but pure essence, just as the alchemists burned, dissolved,  putrefied, congealed,  sublimated, fermented, refined and distilled the gross elements to arrive at the sublime...... It seemed like humus was the result of a similar process, and just as mysterious and ineffable. That was the image that was conjured up for me by reading that post. I was swimming in an imaginal soup. Quite enjoyable, actually, though probably not quite in sync with the informative nature of this discussion. My apologies.

Bryant RedHawk wrote:

jimmy gallop wrote:Humus is
crude oil
dark, organic material that forms in soil when plant and animal matter decays.
this could be used to describe crude oil also.  

Really?

A rather sophomoric statement isn't it?
Crude oil forms under great pressure, humus doesn't form that way, Crude oil is formed only in anaerobic conditions, humus is only formed in aerobic conditions.

Redhawk

sorry didn't mean to interrupt

Personally I think humus is Godde. After having read all the contributions that is my considered opinion. Was trained as an economist myself, we have the same problem, namely that a static science cannot deal with a dynamic world. The problem is with the methodoogy, a theoretical blind spot that at least economists sometimes admit. An analysis of the market that is static produces quite different outcomes than one which is dynamic and deals with relationships of power. Which is why economists are so often wrong :)

I really like the idea of using humus to loosen up clay and will definitely try it. Up to now my method of making soil from the stuff - instead of the bricks it clearly was intended for - has been to make sunken hugels. It has been rough and expensive since the ground requires a pick to loosen it. Eying a particularly tricky spot and will report back in a few years.