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Solvitur ambulando - It is solved by walking

Friday, October 7, 2011

Fungi In the Landscape

A Preparation For the Georgia Master Gardeners Convention


I almost always agree with Fukuoka.  There are real limits to human knowledge, especially regarding what we can truly understand about nature.  I don't think humans can improve nature, and most of our attempts to do so have the opposite effect.  What we can do, however, is learn to imitate nature's design.  If our attempts to understand the subtleties of nature lead us to build food systems more in line with natural ecologies, then I believe we are on the right path.

One of the areas of natural ecologies we have almost entirely overlooked in our food production systems is the role of fungi in the landscape.  At the conference we will spend some time talking about growing mushrooms for the table, because hey, they are delicious and, despite the common American perception, extremely nutritious.  Some of them are world-class medicinals, like reishi and shiitake.  For example, in Japan shiitake mushrooms are not just some wingnut alternative treatment for cancer; they are the go-to medicine for all types of digestive system cancers.  The government has officially held them in such high regard since 1985.  How much more pleasant would a plateful of sauteed shiitakes be than chemotherapy?  We will be discussing more about mushroom medicine at the conference, too.  We'll also talk about the use of fungi in mycoremediation efforts - fungi that filter harmful levels of E. coli from runoff water, fungi that digest diesel fuel spills and jumpstart ecosystem regeneration, and a few other surprising abilities the fungi possess.

For the purposes of this article, though, we will focus on the most pressing myco-issue for gardeners: the role fungi play in the generation of living topsoil.  Would it be an overstatement to claim that incorporating fungi into your garden plan is THE big secret to building healthy, living topsoil?  The answer is an emphatic NO!  I'm going to lay out a strategic circular pathway for significantly increasing the amount of humic substances (more commonly "humus") in your garden soil.  These are the complex and recalcitrant carbon-rich molecules that persist in the soil for decades, even centuries, providing abundant sites for cation exchange, and the characteristic "blackness" of healthy organic soils.

The first question that is probably popping into a lot of heads right now is, isn't that what compost does?  Yes, but not very well.  Only 1-5% of compost is represented by the stable humic substances we're looking for.  That's not all that much.  For the moment think of compost simply as organic fertilizer.  We'll get back to this in a minute, after we jump over to the big tamale.

What creates the bulk of our stable soil humus are the mycorrhizal fungi.  This is one of the three major categories of fungi - along with the parasitic, and saprophytic fungi - and they form mutually-beneficial associations with the roots of living plants.  The filamentous underground body of the mushroom that forms the bulk of its mass is called the mycelium.  Ecto-mycorrhizal fungi grow around the roots of the host plant, while endo-mycorrhizal fungi invade the living tissue of the plant's roots.  From Stamets: "In either case, both organisms benefit from this association.  Plant growth is accelerated.  The resident mushroom mycelium increases the plant's absorption of nutrients, nitrogenous compounds, and essential elements (phosphorus, copper, and zinc).  By growing beyond the immediate root zone, the mycelium channels and concentrates nutrients from afar.  Plants with mycorrhizal fungal partners can also resist diseases far better than those without."

These minerals, these cations, that are made more available by the associated fungi only become bioavailable to the plant if there are sufficient cation exchange sites to host the transactions involved, and those are, most commonly, provided by the molecules of humus that we are trying to build.  The mycorrhizal fungi create these humic substances as a byproduct of carbon induction while mining new mineral fertility from the underlying subsoil and/or bedrock.  And they create a lot of them.  This is what the fungi do for the plants (and the rest of life on Earth in turn), and in exchange, the plants feed the fungi with exudates - sugary carbohydrates, amino acids, fats and lipids - from their roots.  The more of these the plant produces, especially the fats, which are three times more energy dense than carbs and proteins, the more energy the fungi can tap to digest rock and create humic substances. 

That's where the compost comes in.  Compost provides a ready source of rapid-cycling carbon to feed the plants.  The carbon bank in a compost application will mostly be used up within a few years, but it's the kickstart from which an organic system benefits enormously; although it doesn't, by itself, add much to the long-term durability of the topsoil.  The compost makes happy plants, happy plants make happy myccorhizal fungi, and happy mycorrhizal fungi make loads of humus from the subsoil...which makes happy plants, which make...I think you get it.  A positive feedback loop has now been established that will promote ever-happier and healthier plants in perpetuity.  Until it's screwed up again, say, by cultivation and the aerobic acceleration of humic degradation, which is, unfortunately, (drum roll please) the crown jewel of modern agriculture.  It's only a matter of time before food production methodologies that don't respect the fungi and their role in soil building will compromise every last acre of soil on Earth.  This will be agriculture's lasting legacy...if there's anyone around to notice.  Fungi can only dominate the soil, feed the plants, and create stable carbon, if they are left intact.  Tillage destroys fungal networks, accelerates the decay of typically-stable humic substances, and creates the need for prepared fertilizers and pesticides.  Remember, a plant growing in healthy living soil can take care of itself - just look at the nearest wild forest.  Are people fertlizing it and spraying to control pests and disease?  Cultivation is where we really messed up as a culture.  That and generally disrespecting the fungal components of our ecosystem.  Now we know better.

Use your knowledge of this cycle to become an unstoppable master gardener.  People who can do this stuff, who can repair the damage agriculture has wrought upon the landscape, will be tomorrow's leaders.  About that I have no doubt.  The only way that wouldn't be true is if everything just fell apart, and the global population collapsed, leaving many more acres per capita to the remaining human population.  We created our current population by mining our topsoil's capital resources - mined ever-faster on the back of oil - and those resources are dwindling fast.  Even the mainstream agricultural establishment is starting to talk about this problem!  Our charge, as the younger generations alive today, the only task before us really (except perhaps nuclear decommissioning), is the rebuilding of the world's topsoil.  Without it, none of the other peak issues we face today will even matter.  Rebuilding the world's topsoil will automatically restore the dying freshwater cycle.  Both of these dire situations are part of the same systems failure that is becoming more obvious by the week, but, luckily, the repair of one initiates the repair of the other.  In my opinion this is THE task before us in the 21st century.  Renewable energy, social justice, there will never be enough to matter until we get our mineral cycles - the topsoil, atmosphere, and freshwater cycles - back in order.  Praise the people who tend to such items, theirs is a noble endeavor, but the folks who can restore topsoil will rule the contractionary future.  And there is room for all of us in this task.

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References:

Growing Gourmet and Medicinal Mushrooms and Mycelium Running, both by Paul Stamets (Ten Speed Press, 1993 and 2005, respectively) are indispensable resources for all things mycological.

"Changing Dirt Into Soil" by Michael Martin Melendrez, Acres USA, October 2011.

"Carbon Building, Carbon Cycling" by John Kempf, Acres USA, October 2011.

11 comments:

  1. Fifty posts! Hope you guys like this one. I probably won't blog again until after my GMG lecture on October 22nd. I need to focus on that, and we'll be in southern Missouri trail-riding week after next with my dad. Tick tock...

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  2. good luck on the lecture...I have left my garden with the dead stalks of summers last stuff standing and the weeds are in. now what? If I shouldnt till how do I prep this for next spring? SHould I just cover it all with leaves? I dont think they will be heavy enough. have fun on the trail!

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  3. Chickory, ideally you would overwinter your garden with crops covering your soil. My advice would be to just sow a cover crop of turnips, mustards, collards, spinach, carrots, of course onions, garlic, leeks, broccoli, etc, and some nitrogen fixing species too, like clover or trefoil. Whatever residues and weeds you have now, chop them off at the ground and lay them down to mulch the soil. Do it with a weedeater if that simplifies the task. Seed and transplant-in whatever you want to grow over the winter. When it comes time for summer crops, chop and drop the winter ones and insert the summer ones. And add mycorrhizal fungi to whatever you plant in both of these cycles. They should be resident after that. I'm convinced that having living plants in the soil as often as you can manage is paramount. Even if they're weeds.

    Oh, and the most important bit of all to me is not compacting your production soils. Stay on the paths and reach in! A layer of leaves wherever you can stash them is mighty helpful too, especially for carrots. Hope that helps!

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  4. Well, I'll be! I really dig this ode to fungi. Thank you so very much for appreciating my favourite Kingdom and writing about it - especially its role in helping food grow.

    I recently wrote an ode myself to Fungi http://feministfarmerswife.blogspot.com/2011/09/mushroom-story.html- totally different angle but I think the world could benefit from a lot more information on the world of fungi...and other things that we don't understand and take for granted but are MUCH larger than we could ever fathom.

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  5. I'm totally not getting it. I've tried planting root crops (carrots/beets/turnips) this late (and ~2-3 months earlier) in the season, for 3 years now, but they do absolutely *NOTHING* (winter here is 40-50F from November until April).

    I haven't rototilled for 2 years, so I have a basic idea of the soil amends(lime)/cardboard/compost/manure/mulch pyre (I think I should simply *burn*). Particularly, if I transplant garlic now, it simply does nothing until March.

    I think there's some way to create a mulch pile that heats all winter from composting, that you shovel onto the garden. I haven't quite figured that part out yet. And, if you do this composting around a garden in a "greenhouse-like" environment, it creates heat for winter crops. Again, no F'n clue how to do it...

    Just because I believe it all ends with a Mars environment in 100-300 years, doesn't mean I gave up. Quite the contrary - I will go down doing that which I believe we all should have done...

    Oh, and should have poasted this diatribe to your lawn-mowing poast from 2-3 weeks ago:
    "The gardeners around here like to use 'mushroom compost' (old growth clearcut bark chips) in their gardens, and guess what - it works pretty damn 'well'"

    Can't quite figure out how to move solid carbon from "here" to "there", without "here" becoming depleted. Need help, ASAP!

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  6. Let me just state that I am moving more towards having annual fruiting trees/bushes everywhere spread out, and that it is working pretty well (for the past 3 years). My raspberries produced about 2 gallons of fruit late spring, and 1/4 gallon late fall [my blackberries are mainly to keep birds/squirrels coming here to fertilize/manure, and I have a bird feeder that they both eat from all season])...

    And to be more clear, my winter crop plantings do produce plants, that remain very small, and mostly stagnant all winter. Is it the fact that the roots are there, and the soil fungi remains in those roots, and if I top those plants next Spring, the soil will be more productive? And what about rotating crops (tomatoes primarily - squash as well, but now I'm also using beans/peas mostly to nitrify the soil).

    If I understand what you're doing, you take a new plot of land, and mulch it with hay/straw (1 acre of harvested straw, to 1/8th acre garden mulch)? Do you see my dilemma?

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  7. OK, I'm F'n spamming, but I've had chanterelles growing in my garden the past two years (hope to see some more soon). And, I've walked around the local neighborhoods, grabbing mushroom caps and placing them in my garden for 4-5 years... Slippery Jill, Amanita Muscaria, Liberty Caps. I haven't seen any of those 'shrooms catch on yet (slippy jill was here from 20-16 years ago, but it died off)...

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  8. That's a lot to take in, Ix! OK, here goes. You don't really want your garlic to grow until March. The best timed garlic has just enough warmth in the fall to kick down some roots (any green growth would be a waste of energy) and chill through winter, then come up strong as the days warm. In your climate, like at our farm, it's probably ready to harvest by June.

    I tend to think that you don't want a lot of active growth in the winter, unless you have a low tunnel to protect the babies. Certain things might do alright, like kale, mache, or Asian greens. But for the most part, you're just getting ahead for early spring. If you can slide in a round in the fall, count it a bonus. I'm hoping to see a couple dozen heads of broccoli before winter arrives for real. The rest will have to rest for spring.

    Mushroom escapades sound interesting! I just spored a big bed of Stropharia (wine caps) that seems to be doing really well. Mycelium going nuts!

    In my opinion, having plants in contact with mycorrhizal fungi (and the rest) is the key, along with a solid carbon bank on the surface. To help answer your question about robbing Peter to pay Paul, ideally you want to build a system that fertilizes/mulches itself. That's the ideal in a perennial polyculture. You don't want to have to keep importing piles of biomass from "somewhere else".

    My main thesis is that plants are the producers that fuel the system, and humans are one of the animals that consume that primary production, ostensibly leaving a gift of manure behind (although we both know how often that happens in industrial cultures). Something we need to work on before our systems will ever function without imports. But a plant's aerial biomass should serve as ample mulch for the system, once established, assuming you don't take away more than 97.5% of the mass of the plant, which is the fraction made up of sunshine and atmospheric gases. I would leave a lot more than that if you wish to actually enrich the system. Crops like tomatoes, squash, beans, and corn make particularly good mulches. Crops like cabbages, where you remove so much of the plant's mass, are questionable.

    Case in point: just recently I've plugged Swiss chard into a bed behind last spring's cabbage and it's not growing very fast. A second round of tomatoes, plugged into the detritus of the first round, is going crazy without any further imputs. Could be that the cabbage bed was fallow for a few months between crops, but hard to say. I think with this method of production, it's best to keep crops in the soil.

    And lastly, are you, in fact, using mycorrhizal fungi? That appears to be the link between inorganic mineral fertility and organic nutrient cycling.

    Let's hope for a carbon-rich, verdant horticultural paradise, enabled by thoughtful people, instead of the Martian desert you so drearily prognosticate!

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  9. I have had a mutant chinese mustard/turnip plant that grows crazily all winter, and all the leaves/flowers are edible and taste *mediocre*. It's funny as hell seeing this plant about 4-5' tall and 3' diameter, bright green/yellow, in early March - but glad to hear that I shouldn't expect early garlic.

    I do like the idea of spreading garlic during the fall/winter, to root and bring in soil fungi/etc. And no, I haven't purchased any fungi, ever. Most problems I've been facing are beds which have been fertile producing grounds for years, but now do that "fallow" bit...

    I want to keep my gardening as simple as possible, and I adore annuals - WhereTF is my annual tomato plant! Hehe, here's an anecdote of fail: I've tried for the past 2 years to clone the best tomato plant varieties outdoors, brought them indoors, and replanted them next season. They really didn't perform any better or worse than the plants I started from simple (mutant/GMO fertilized?) seeds in Feb/Mar. And here, I thought that I might get some killer 7-10th generation "flowering plant" that kicked all the rest into humiliation...

    What is it, that will actually stop this over-population, over-pollution, over-burning of solid carbon, and over-clearcutting of the last remaining rain forest sequestration systems? The fuel sources (oil/gas/nuclear) will allow them to continue that exponential pathway for about a century (and a half). The ocean does continue to absorb CO2, thx *Ghad*, becoming ever more acidic (and killing off all the [barrier] reefs)...

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  10. BTW, thx for the reply. I've got Gaia's Garden, and Teaming with Microbes (per your suggestions) - I've read a lot of the former, but little of the latter. Prolly worth reading the latter, about now. I'm certainly believing my years of rototilling/rotating crops did nothing to help the fallow issues. Two things I found extremely useful this year:
    1. Plant lots of herbs all over, and spread them thinner and thinner all around, *EVERYWHERE*. This resulted in not having to water my main crops this year (soil water retention). And, it brought in so many pollinators (about 6-7 different bee varieties), that every flower ended up fruiting (it became quite scary without beekeeper gear, as 20-40 bees per square yard were always swarming).
    2. Plant (sugar snap) peas/(bush) beans all over the place, near crops/annuals. This seemed to help reduce (nitrogen) fertilizer needs, and gave me lots of tasty raw greens for free.

    I spent a lot of time the past decade, trying to perfect the "Indian crop" method - beans, corn and squash, all in a row. It got progressively stunted year after year, for the 6 years I tried it (rotated with the tomato bed, and rototilled - maybe I should have done it all *IN PLACE*)...

    I've have emerald green (tree?) frogs appear in my garden the past 2 years, after I brought Amanita Muscaria caps into my yard/garden. But so far this year, *nada*. This makes me incredibly sad - those bad boys were so damn cute, and so damn rare (and prolly a sign of the blight/death humans have brought to the biosphere)...

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  11. Just saw my first hummingbird this year! Same old emerald-green variety, with a hint of purple on his throat. He was hitting all my raspberries, and *totally* avoided my hummingbird feeder - lulz. Still getting fall raspberry fruits, much more tasty than that sh!t my sister always buys from the stores (she even x-planted some of mine, but kept them in underground pots, that cooked the roots during the summer). WTF - fear of invasive raspberry/blackberry crops? I mean, learn how to use a "Ghad Damned" pair of hand pruners...

    Also, the chanterelles came in hardcore this year, lots of tiny caps all over the garden.

    No emerald green treefrogs spotted yet this year, but saw plenty of garter snakes. And plenty of feral cats, squirrels, and finches/blackbirds/robins/bluebirds (crows and hawks/falcons too)...

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