Interesting topic. The most salient point from your link, IMO:

"soil improvement is slow and takes place over decades".

This is what new gardeners (and many not-so-new) most need to understand.

Bacterial N-fixation is the key part of that slow improvement.

I am sure improvement continues for decades, but I remember the fall that we put down 4-6 inches of mushroom compost and left it through spring. We had a new garden that year. Transformed.

JCP, in the process, you may have injected the soil with a lot of flora, and that contributed.

OP:Surely a soil can be improved over decades, but I bet 90% of the improvement can be had in the first three years for clay, and possibly six years for sand. This assumes massive amounts of OM. In fact, I am not even sure you can improve a hugelkultur bed at all after a few years.

Yeah, that was the good stuff - right from the mushroom farm, by the cubic yard,

Agreed, Glib. Gotta go, for now. M

Ah, another STD.
(soil test discussion.)
At least it sounds as though the great P shortage and resultant end of civilization as we know it, may not come to pass.

I still believe in cheap (free to ten bucks) soil tests from either one's county extension (my county is free) or a University Lab (U Mass -- $10, includes micros and heavy metals) to tell things like PH, heavy metal levels, and whether you've adjusted any deficiencies that showed up in a first test. Okay, so the info is saying that the "deficiencies" might not ever have been there. But can I get one of THOSE soil tests for free to ten bucks?

Also, I believe in Evidence Based Research (in medicine and in gardening.) I had the experience of adding 4 -6 inches of manure one year and having a completely transformed garden. The area where the manure pile sat is still particularly fertile, growing each crop huge as the different crops rotate through that section.

I got the soluble salts tested (an extra 5 bucks) after several years of adding manure, and they were fine.

But since I am lazy, I like the vegetative waste only idea, and could be happy to never shovel manure again :)

Out in the forest or on the prairie with Ma Nature the only one at work improving the soil it can take years. We know that it can take one hundred years for Ma Nature to make one inch of "topsoil" However, in our gardens we can, because we add (or should) far more organic matter to the soil the improvement will take much less time, although getting the Soil Food Web population up and working can take longer.
You can work adequate amounts of organic matter into the soil and in a few weeks have some good looking soil, but the Soil Food Web may well take 3 to 5 years to build up to adequate levels.

High use of manure can burn out soil just like chemical fertilizer, especially a sandy soil. Most small veggie farmers rely heavily on rotary tilling and dehydrated chicken manure - bad news for soil with or without organic certification.

why does the food web take so long to establish itself? The bacteria are mostly there, and if not, any cold unfinished compost will inoculate a soil adequately. any addition of leaves, twigs or chips from a dead tree is bound to bring in some mychorrizae. what else is needed? earthworms show up in weeks.

Any population will evolve and shift towards an optimimum in a steady enviroment, but the environment shifts as the organisms shift so there is no real steady environment for a long, long time. Even when a population or set of populations become more or less homeostatic with it's envrionment, randon genetic drift will continue to push change along at a slower pace, altering the enviroment and it's eventual populations. Added to the complexity are changes in the metaenvironment, such as inputs from the gardener/farmer, selection of crops, and long and short trending weather cycles. This all effects the biological pools of fertility. Good answer, eh!? ;)

MinDFW

Yep. I see nothing there that works on a ten years scale.

Add in crop rotation. My garden is 50% brassica, and I make it a point of alternating brassica and non brassica in beds. Now brassica does not enter in mycorrhizal symbiosis, most other crops do. My garden will naturally evolve towards a simplified food web, with generalist organisms predominating. But that probably happens in most people's gardens, so long as they rotate, because different veggies favor different organisms. It will also happen in large farms.

To expand on Mackel's point above, soil is just a part of an entire ecosystem, and that includes plants, animals - burrowing / grazing / hooves trampling, elephants stomping , etc. along with an equal or greater biomass of insects above and below ground.

Now, instead of hunting/gathering off that bounty, we remove everything but the soil, and wonder what went wrong.

I imagine that the long timeframe comes from the "dual mandate" faced by new gardeners. They want to improve soil, but they want to get crops in too. Obviously most new gardeners are focused on the crops.

A program of amendment, green manure, and mulch might bootstrap the food web in a couple seasons - but you'd be eating legumes for the duration.

and yet you can quantify e.g. soil turning by animals. Darwin, and many other after him, found that most soil turning is done by earthworms. do we really need elephants for optimal soil?

I also disagree that you have to eat legumes for three years. Say you start with suburban soil, completely devoid of anything. You bury some leaves that had been sitting under a tree to get things going. First year, sure, legumes, but if you bury wood you should be able to get decent other crops in that same first year. Second year you can get anything. I actually started an orchard in such soil three years ago. 40 cubic yards of chips and 6 tons of manure after, plus allowing thistle to expand for the first two years, has given me good soil most everywhere.

In some climates, "a couple seasons" is a year or less.

Minus massive inputs of mulches and/or compost/manure, improvement is very slow, IME. Said experience almost entirely in various types of sand.

My mother had some land and in the land was a weed patch which got mowed once a year. It sat there for 30 years, and before I left for college I planted a small orchard (24 trees). Smack in the middle of the gummiest imaginable clay, this patch had 4 inches of fine black dirt, just from the weeds. Lots of dock and burdock, which both have long tap roots.

So, sure, decades without intervention, but mankind has leaves and wood chips for a much faster evolution. Every necessary organism can spread quite fast given food, water and tilling.

Glib-

It's seems like your'e trying to make a point, but it's not clear what it is, other than you seem to disagree with something. Please consider the information provided as a whole, and provide whatever feedback that you might add, and particularly with any further research.

Focusing on one sentence that sort of grabs, when there are numerous pages of information (in 2 separate links)provided seems to obscure the thrust of the subject, which involves cutting edge soil testing, at the frontier of what we understand about soil feritility.

What stands out in your last post is tilling, which can only be performed once for an orchard, and food, which could mean anthing, from life forms within the soil to sugars produced in the plant to ammonium sulfate.

I think I know what you're trying to get at, but please add something nobody has considered, for example, and not just focus on personal experiences, if you wouid. Personal experiences can buttress what we have to contribute, but that's it's main purpose, a buttress. Bring something in that is universal, that can be said about any soil.

Sorry if it sounds like I'm getting on your case, but each post seeems to say something but what is it? Back up what you have to say, add something nobody has considered. Contribute something as food for thought, even. Thanks, Man.

MinDFW

This post was edited by Mackel-in-DFW on Sun, Jun 1, 14 at 20:24

Here is the point, in part made by Pat: long term (decades) evolution only in undisturbed systems, which is of scarce interest here because we interact with soil to an end (crops, or perhaps lawns, or pretty backyards).

Evolution of man-modified systems under decent practices about three years except very few special cases such as beach-like soil.

Glib-

Got it. But that's one sentence that you've addressed from two links. It's not even a central point, and a hypothesis that diveges from the international group of soil scientists that worked on the information provided.

I would tend to agree with the consensus within the scientific community, that if handled right, the biological pools of fertility improve for many, many years, as you may be right, but as of yet you haven't provided compelling reasons to disagree with the current, frontier edge of the science. Mainly because you don't objectively delineate how a 90 percent improvement can be measured with any sort of precision. It sounds like a rule of thumb, and perhaps a very valid one.

My own experience is that our soil has improved every year for ten years straight, with four of the last ten years no fertilizers, organic or otherwise, added. The soil continues to get more fertile with no inputs other than non-manure based composts and mulches.

I do thankyou for your clarification. I interpret what you said to be exactly what you said, that within tree to six years, signigicant improvement takes place.

Are you indicating that no fertilizers are essential after this point, as in the case of our soil and purposes? I grow fruit trees, vegetables, and some exotic bamboos, along with native trees and plants. It's not clear what you mean after 3-6 years what criteria has been reached.

The rule of thumb that you offer does not appear to bolster nor contradict the central theme, which is, BIOLOGICAL POOLS build up and act as reserves for plant nutrition over a period of a longish time..

I'd add and my apologies if misinterpreted, I believe just the opposite of what you're suggesting on another point, I believe that in a stable monoculture, the soil reaches a biological homeostais SOONER than with multiple crops and multiple inputs.

So, if you'd like to respond, I hope the discussion can be open-ended as the link itself suggests.

Have you read any of the links, or are you responding to posts? Have you read about plant tissue testing on asktheplant.com ? Do you understand that the new tests offer realtime solutions, unlike the traditional tests? Do you understand that this is the frontier, and was never meant to be "proven" nor "disproven"? That will be the job of the next generation. Thanks.

M

Tangential:

Around these parts, where the geology is largely gravelly sandy stuff, I notice that the lawns that are habitually raked of leaves every year and not fertilized, are really spare run-down environments. Poke down through the thin thatch and there is nearly no topsoil. This after many decades - even though the lawns are cut with mulching mowers, the monoculture does not seem to harbor enough life to build any soil. The situation would be different on a silt or clay base.

I see the same thing in florida sand - a pasture or lawn can be in grazed/mowed grass for a century and there will not be an ounce of humus created. Let it go to brush for a decade and there will be at least a little OM build-up in the soil.

My experience is in pretty good soil. Even scraped and leveled suburban lots in SoCal tend to be valley soil.

That said, where I'm really coming from is that if there are paths to building soil, there are surely accelerated paths.

I would think those would be paths where soil building was given high priority, early on.

I agree with everybody's main points, with the caveat, as they say in medicine, to "first, do no harm". I guess Kimmsr hasn't decided to wade in yet. ;) M

This post was edited by Mackel-in-DFW on Mon, Jun 2, 14 at 0:01

"if there are paths to building soil, there are surely accelerated paths."

Agreed. I suggest that only at the expense of degrading soil on some other spot of spaceship Earth, however. So we segue into the subject of do the least harm.

Is it less harmful to mine minerals from arid or desert regions and transport them long distances, or to run down the soil life in forests and meadows by using them as farms to produce biomass?

I think the optimum ratio, pnbrown, is to use about a ton of local OM for every pound of chemical fertilizer you buy at the store.

2000:1

I'm referring to mined minerals, rather than synthesized fertilizers. Example:

Dusting a field with lime vs spreading compost. The compost brings a quicker and bigger boost in production, but at the cost of whatever areas grew the feedstock biomass. The lime is dug from a quarry, OTOH, a relatively small area that can furnish a lot of material.

I get what you're saying, I think I'm on the same wavelength. The best local OM are surplus and by-products, like bark of trees cut for pulp or lumber. Even better, the municipal composters stop material from going to the landfill. So is every gardener who stops at Starbucks.

In terms of good intentions gone wrong ... fish meal is good when it is a by-product, but I understand that some anchovies and sardines are/were caught for "direct to fertilizer." That's bad. I'd rather have MiracleGro