Successional Soils

[The Helpful Gardener]

Greetings!

Alex asked for a quick bit on how soils can be made organically fertile from a nuthin'-but-sand start. I willl go him one better and talk about how Nature does it from scratch; on bare parent soils, in other words, rock...

How do we start from that hard barren rock, be it an old cliff face or new volcanic spew? Simple, we do what we always do in organic gardening, we add humus...

The first guys we would want to encourage would be lichens, who's microroots, along with the first weathering, begin to work into the surface of the rock, fissuring it and speeding surface decay. As the lichens die off and mix their bodies into the decaying rock, we begin to get our first minimal layer of soil, at it's most highly bacterial state (very little fungus at this point). But that thin layer of soil is enough for our first plant material, mosses, who begin to add both their detritus and rooting actions, and the whole spectrum of plant biology begins to pick up, including our first fungal hyphae. But we still have a very bacterial soil, with fungal to bacterial ratios around 1 to 100...

The next level we bgin to get our first vascular plants; early grasses and weeds; the kind that show up in any profoundly disturbed site, be it volcanic slope or bulldozed plot (for Nature does not care how the soil was disturbed, simply that we were knocked back to the start). They begin to develop fungal associations with mycorrhizae and develop an area of high fungal/bacterial activity around their roots called the rhizosphere, and our F/B ratio increases to around 1 to 10. Still this is a more nitrate rich soil as bacterial soils tend to have higher levels of nitrogen and not a lot of plant use yet. Keep that in mind; high nitrogen, low oxygen soils are what weeds like... but as these weeds die their roots, high in carbon, decompose into the soil. We start to shift the carbon to nitrogen ratio towards carbon, and fungal decomposers are far more suited to carbon breakdown than bacteria...the tide starts to swing...

Now as we add more species and continue our shift to a fungal soil, we start to see some plants of use in the mix. As F/B gets toward 3 to 10, we start to see turf grass doing well. Our soil is getting more aeration as fungal hyphae and roots bolstered by mycorrhizal assocations probe deeper and open soils to gas and water exchange. Our soil continues to get better...

Now we are at a 7 to 10 F/B, and the soil begins to support some grains and our hardier veggies. The organic content of our soil is around 5%, and we are in the happy place for growing most veggies, As we get near 1 to 1 F/B, most any veggies, annuals, row crops and hardier turf is going to thrive for us, but trees and shrubs will still struggle...This range suits Man just fine, but it is not Nature's final goal; Mother wants everything forested, so we press on...

At 2 to 1 F/B, the shrubs start to show up and as we increase towards the higher ratios we get more and more woody plants including trees. At 5:1 the trees are adding more and more carbon to the soils (wood and brown leaves are high carbon inputs), they become more and more suited for fungal growth and less so for bacterial...

As we shift our F/B above 5:1 we start to see more and more tree species and as we get above 100:1, our first evergreens showing up. This is Natures goal for most temperate ecosystems; to reach a climax forest of evergreens...

So as organic gardeners the best bet is to move the system along to the place we want it for our crop, and then hold it there through manipulation of available chemicals. By shifting our soil near to that 1:1 F/B, we have the place we need for veggies, perennials and lawns. But how do we get that?

By interrupting the cycle anywhere AFTER the 1:1 F/B. Nature interrupts herself all the time; forest fires, floods, buffalo or wildebeest hooves times a million, all these set us back a succesional level or more. By simply adding in bacterial cultures and fungal structure, we reestablish the natural cycle of soil and interrupt at that perfect place on the cyle for humans. If we add too much carbon we assist MOther in the successioanl chain to the detriment of our own crops. If we interrupt the cycle with chemical applications, we kill fungal structure first, promoting a high nitrogen soil with less oxygen. Who likes that soil best? Weeds. SO why should we be suprised when they show up?

Sure nitrogen fertilizer short-cuts the system and feeds the plants directly without bacterial or fungal systems like Mother does, but it acts on the succesional biology in the same fashion as that fire or flood. Now the plant becomes reliant on the fertilizer and begins to lose some of the diversity of nutrient it was recieveing in the natural system. There's a problem, and pesticides are used; another successional level lost. The plant is weakened further and a fungal problem arises; another chemical, and another level lost. This vicious cycle continues as we slide back to what is for Nature's purposes an early succesional soil...

For those who think I'm barking mad, you are correct, but this is all true anyway... This article shows how we are studying this natural release to this day, and there is still a LOT more to learn, but this is all basics I have given here... here's what the real scientists are doing...

[url]https://findarticles.com/p/articles/mi_m2120/is_n8_v75/ai_16541430/pg_2/?tag=content;col1[/url]

And for a bit on how organisms in soil don't just release nutrition they ARE the nutrients...first we get bacteria and fungii eaten by protozoas and such... (Alex, this first article is the meat and potatoes of what I've been talking about...)

[url]https://www.jstor.org/pss/1942528[/url]

then the the bigger nematodes eat all them...

[url]https://plpnemweb.ucdavis.edu/Nemaplex/Ecology/fertil.htm[/url]

And then the worms eat the nematodes and the rest as well...

[url]https://soil.scijournals.org/cgi/content/full/68/1/116[/url]

And bada bing, bada boom, youse got plant nutrition...

Questions?

HG

[hendi_alex]

Whoa, systems overload!

First, my compost is mostly high carbon browns from the leaves dropped by the various oak trees in the yards. This year I've been adding many more greens as am harvesting 'weeds' from the yard and adding sour grass of two types, and a few other dominate invasives in the early spring yard. But still, it sounds like your saying that my organic material, especially if added before fully composted, is adding way too much carbon, to the extent that I'm accelerating the soil past the veggie stage, and am mostly helping maintain the 'grow a forest' stage. By volume my composting material is mostly leaves, by weight it is mostly and aged manure/sawdust mixture, still pretty brown. The concoction, even this year with extra greens, is likely less than 5-10% green.

In the totally tree covered sections of my maintained yard area, mosses and lichens thrive on the soil surface under the canapy. The soil is so heavily sand and dry, that the mosses while widely covering those areas is generally not thick and lush as the conditions are just too harsh, especially with the past several years of less than average rainfall.

The open portions of the yard, if just left to its own and not maintained, would start out as a somewhat sparse covering of coastal bermuda, centipede grass, and a variety of weeds including red sorrell, sour weed, some little lavender spring flowering invasive, and a few other dominant, aggressively invading species. If I went for a year without cutting the grass, dog fennel, broom sedge, dandylion, golden rod, and a couple other large invasive species would come to dominate the dry sand area.

My gardening areas mostly consist of raised beds which contain a mixture of leaves, composted mostly browns and manures, synthetic soil of the miracle grow or stay green variety, and lots of earth worms. The established beds have had lots of the composted material added and have had individual planting holes enriched, in most areas for several years. One major bed area, covering most of the wildflower gardening area, has very black soil, that black color comes from having burned the original house on this site and having graded the remains into the soil, so lots or ash and lots of carbon in there. The newly tilled areas, just added this year, have enriched planting holes for tomatoes and melons, but the beans were planted directly in the sand with only the addition of a balanced chemical fertilizer. The soil in this area has the feel of pure sand, is lightly grey, and turns yellow about eight inches down.

So that is where things are now. The challenge will be to establish a plan to get where the soil needs to be, near that optimal 1:1 ratio for garden variety plants. And the question still remains, can a person move in that direction by quitting with chemical fertilizers cold turkey, and using other more sustainable methods of fertilizing, such as fish emulsion/meals, various seed meals, kelp meal, bone meal, etc.

Will re-read your post. Will follow the links and read that info. But at this point am interested in establishing a plan to get from point A to point B. But one that will allow continued successful gardening during the transition.

Thanks for taking the time to write this informative post regarding the living soil and its succession process.

One final note, when moving here in 1979, one could barely find any kind of earthworm on the property. There was simply not much for them to eat and the conditions get very harshly dry during the summer. Now earthworms abound, and they can be found amywhere that a bit of organic matter is available, if at least some minimal level of moisture is maintained during the summer heat. Hopefull, this population of worms will be very helpful in the efforts to make a transition in soil structure in our gardening areas.

[The Helpful Gardener]

Alex, don't forget you are interrupting successional progress with chemical fertilizer, so the chances of moving PAST 1:1 F/B is not likely; nearly impossible really as fungal hyphae are the most effected by the use of ammonia salts. I am saying you are working against the natural system in favor of the man made system, which is working both for (feeding directly)and against (eliminating the natural supply mechanisms)the plant. You are not getting the full benefits of the compost you are adding (Nature will not be denied and you are getting some) and it is not being allowed to move your soil down the successional chain the way it would like to...

Your sandy soil IS working against you to be sure, as the biology, ALL the biology, from bacteria to worms but especially fungii, is reliant on the humic content of your soil for both habitat and sustenance. No humus, no biology. So you have started step two in famous fashion, but you have skipped step one; Stop Killing The Biology. "Hybrid" organic systems are NOT organic; little deviances from Nature's model make big differences. When plants and soils aren't juiced up all the time, we get healthier plants and less disease. Biodiversity checks the pathogens that are really only 5% of total biomass. Like people, healthy plants on good diets get sick less. It's really that simple...

My favorite tool for increasing biology across the spectrum is compost teas, but we need to get the humus into the soil before we start dumping biology on, like colonists dropped in the middle of the Sahara...Alex, I can't promise no bumps in the road, but we can start moving towards organic culture immediately. Let's make one step right now; lose the blue goo and try composted chicken manures. I am not a fan of composted poultry manure long term, as it has a water soluble component, but because of that it stands in for chemical fertilizer as far as plants are concerned (and we are recognizing a 60% reduction in water solubility). This should allow plants and soils to move towards biologically denser populations with out a big bump. We can switch to a more fungally focused food like fish hydrolysate in a few weeks, but first thing first. Stop Killing The Biology.

Keep the questions coming...

HG

[hendi_alex]

I think that I'll address the easiest areas first, and let the more difficult areas stay in kind of transition for now. The established raised beds and defined vegetable gardening areas are high in humous and in earth worm activity. But they have been contaminated with chemical fertilizer. As of today, will not add any more chemical fertilizer to those areas. Will instead add my concoction of organic meals and will generate some teas from compost, from the earthworm bed, and from some manure. Will also plant legumes or other nitrogen fixers in those spots as often as possible. The other major areas, naturalized beds and newly tilled vegetable spot will continue to get humus, but will also still get their hybrid blend of nutrients. Some will come from chemical fertilizer and some from my organic sources. After the main garden areas are converted, will try to wean these larger parcels, one bed at a time. With the goal of converting totally away from chemical fertilizer in the yard within two seasons.

[The Helpful Gardener]

Alex, you are my new hero, and the reason I come to this site daily; the one person who switches up is enough to keep me coming back (it's like that one great shot I manage to make in eighteen holes that keeps me from throwing the clubs in the water and quiting forever )

Don't think of the soil as contaminated; those chemical fertilizers are likely long gone. You used water soluble fertilizer, and it dissolves as many times as it gets wet, so it wasn't in your beds or near your plants for long; it dissolved again with the first big rain and washed into your local water table or nearest surface water, where the phosphorus likely bloomed algae. The nitrogen continued downstream for the most part until it got to the ocean where phytoplanton bloomed like the algae did (Both these actions create low oxygen situatios and massive sedimentation as the algae or plankton die off; bad in either case). This is why you need such excessive NPK numbers in chemical fertilizers; it just isn't there but for an instant; it is not stable or sustainable in the soil for long...

Your soil is more damaged than contaminated; you have cycled it back to an early succesion, high nitrogen-low oxygen situation by breeding more bacteria than fungii (remember that bacteria are nitrogen pigs themselves, with C/N ratios around 5:1, our veggies are more like 30:1). As long as you maintain high nitrogen inputs you will stop your soil at that place that favors what plant? Weeds. It is when we move the soil to a more fungal state that we get more oxygen (remember our bacteria are aerobes and use a lot of soil's oxygen level) Speaking of which, NO manures in compost tea. Composted manures, o.k., but not straight poop. It is loaded with E.coli and other fecal coliforms that are anaerobic bacteria; they can survive oxygen rich environment but are just waiting for it to get a little stuffy (like a nitrogen rich, oxygen poor environment; sound familiar?). It is simply not advisable to roll the dice there. We'll talk tea on another thread sometime soon...

If it sounds like I'm down on bacteria, I'm not; they are the mast food source for this ecosystem and integral to organic culture. It's just that we have beaten down the true star of the atmospheric carbon storage crew, fungii. We can't break down highly carbonous material without them, we can't grow trees without them and we can't bake bread without them. They do more to create soil than any other kingdom and we are indebted (literally, as fungii provide service we could not do well or readily for any amount of money) to these least organisms we have beaten in a vain attempt to surplant a very functional (and pliable) natural system. I can make this system work as well as any of my chemical inducing neighbors, and better than most of them (I am working on Dick as he is a good neighbor, a talented gardener, and a most well-humored and reasonable man. I suspect you two would get on well, Alex...)

Thanks for making my day...

HG