Grow Your Own Soil: Compost Crops

Readers will note that I am HUGE on living soils.  We moved into a dead, denuded landscape and have spent the past 5 years dutifully rebuilding them.  The single most important thing in healing soils is to add organic matter – essentially getting carbon back into the soil.  Why?  Carbon is the primary building block of all life and it is the fuel of the soil food web -from the zillions of bacteria and miles of fungal hyphae to the worms that feed on them.  We’ve been trucking in organic matter for years now – mostly wood chips, but also straw and manures; by the ton.  In fact, over the past five years I would estimate that we’ve surpassed 20 tons of raw material that we’ve either added directly to our soils (manures), or mulched (wood chips and straw).  That may sound like alot, but at least half of the carbon is lost to the air as part of the decomposition process (no fears for global warming as the carbon in wood chips and manure was atmospheric carbon just a year or so ago before it was sequestered by the plants), plus to add an inch to a 1/4 acre (11,000 sq ft) which is my yard (minus house and driveway)  you need to have about 9 tons of compost.  That’s 34 yards of finished compost, or over 100 cu yards of raw material.  Helping others get to this point is why I own a dump truck.

The result is that our soil is teeming with life and the gardens are really starting to “pop” this year with trees adding multiple feet of growth, 5+ cuttings of the Russian Comfrey, and sunflowers over 8′ tall.  We will continue to “uppen” our soils with compost and mulches for decades to come.  But I am trying to do this on as low of inputs as possible.  In the last 5 years we have built our garden soils up and the lawn is getting healthier every year.  It is time to try to see how sustainable I can make this system.  It is time to start growing my own soil.

To grow your own soil you need plants that pull carbon out of the atmosphere, which of course all plants do, but some do it really damn well.  I must tip my hat strongly to John Jeavons and his work on sustainable gardening here, but for annuals the choices are not too hard – what gets really damn big, with a thick stalk?  Think sunflowers, sorghum, corn, quinoa, amaranth, etc.  Add in all the small grains if left to dry out into straw and you get the idea.  Perennial crops are also money as well.  There are a wealth of BIG plants in the tall grass prairie – my favorites are cupplant, giant Joe Pye weed, sunchokes, and the myriad perennial sunflowers like maximillian and ox eye.  The true Big Guns in this area are rapid growth trees, often referred to as weeds, harvested as coppice such as willows, box elder, black locust, and even chestnut and ash.  Other “weeds” like lambsquarter, ragweed, and buttonweed get 6’+ tall , and even invasives like buckthorn coppice well.

Today I spent an hour touring the back yard with my Big Az 10 cu ft mulch wheel barrow, my sickle, and my new brush axe pulling weeds, hacking down old raspberry canes from last year, cutting back insurgent sunchokes, and taking the 4th cutting off the 60 or so russian comfrey I have around the gardens.  That produced an immense amount of green material – piling it into my utility trailer I easily had 80 cu ft.  That is far too much nitrogen for a pile so then I got out my loppers and a pruning saw and took some prunings from the buckthorn out back and two of our willow shrubs.  It wasn’t enough, but in a few years the 2 dozen box elders and  willows I have planted will be on line.  Here are the results.

about 100#'s of material, but dang is it bulky. Brush Axe is leaning on the trailer.

That is from one lap of the backyard – I can do this about 3-4 times a year at present.  In years past I just threw all the weeds into the compost bins, but it doesn’t work too well as the stalky stuff takes too long and the full size leaves mat up.  Now with the Bio-80 shredder it makes marvelous weed puree.

Entropy ala weeds. At least half that pile is/was comfrey so the compost will be awesome. The recycling bin is the chipped tree prunings - not enough to offset the greens, but its a start..

Now the Bio-80 is powered by gasoline, and I am likely to catch flak in the comments for burning dead dinosaurs to save the world.  I agree- its not ideal.  But I am building a transitional system and am not afraid to break some eggs to make an omelet.  The chipper is only 5hp and ran for about 20 minutes using less than a cup of fuel.  In future years I hope to find a way to power the chipper on methane from the ‘Midden or ethanol from a local co-op.  But for now I’m in bed with BP on this one.  One very cool option would be to use a chicken “shredder” to break down the green material – 4 layers in a confined pen would make short work of this over a week or so of adding an inch or two a day for the girls to scratch in.  Of course that is illegal here.  Working on that too…

This bin is 40" cubed and is about 66% full. This will settle almost 30% in the coming days. Making soil takes ALOT of plant material. Plant more trees!

Finally, it takes ALOT of plants to make a yard of compost.  A yard of finished compost weighs about 550#’s.  So the 100-150#’s of material that I put in, most of which was water that will evaporate out, is just a start. But every journey begins with a step.

I am very proud that this bin. When I add another weed lap in September, plus all the corn, cupplant, sunchokes, and sorghum stalks form the yard this fall, this cu yard of finished compost will be 100% homegrown.  As the gardens mature, I will begin getting leaf litter from the trees and willow and box elder coppice to add to it.  My gardens, minus paths, are about 3000 sq ft – that means that 4-5 cu yards could cover it all with .5″ of compost annually, which is alot if you are only maintaining fertility.  I can do that in about 5 years if I add more coppice trees; I am convinced that I can sustain the fertility of my gardens without additional inputs.

We can do this.

Be the change!

-Rob

Advertisements

Food + Fuel + Fertility = The New Paradigm

Food. Fuel. Fertility.   Of late, those 3 words hammer through my brain like a sledge whenever I get going on a new project.  The reason is simple – I am convinced that our agriculture has to do all three if we are to build a new culture to survive the new reality of Climate Change on top of Energy Descent and our burgeoning billions.  We talk and talk of sustainable culture – but I don’t want to sustain what we have now – the fear, the pollution, the waste – I want something far better.  We need a Regenerative Culture. The Age of Exploitation must come to an end – the Age of Healing has arrived.

The Methane Midden is a good example of this thinking.  While significantly on the energy/fertility side with its 4-6 months of hot water or methane on top of the 4000#’s of compost, it is also planted with squash and tomatoes to produce hundreds of pounds of food.  The system is still being tested (the plants aren’t loving it) but the potential is immense.  7 weeks in and the pile is still over 125 degrees – with no turning or maintenance at all.  Dang!  Tomorrow I am going to harvest several hundred mature lambsquarter that are 9′ tall to be shredded for the methane feedstock.  Much more to come on that project!

With that task of harvesting tall stalky plants in the back of my mind, this morning over breakfast I went on a fantastic internet fueled thought tangent on the feasibility of a fuel tweaked Three Sisters guild.  It is so simple, which is why I am so excited.  First – take the standard Three Sisters of corn + pole beans + winter squash and swap oilseed sunflowers for the corn.  Why?  Because my car and 2 wheel tractor run on diesel.  Journey to Forever says that you can get 102 gallons of oil from an acre of sunflowers – 43,000 plants on 1′ spacing.  But we are wanting a polyculture so we will need to let some light in by spreading the sunflower canopy a bit – say cut the spacing in half to 25,000 plants or so.  That still leaves enough plants for 50 gallons of oil if we use oilseed varieties.  Then take the understory and add back in the squash.  Monoculture will get you 10-20 tons of squash per acre.  So again, lets cut that down a bit and say 18,000#’s.  That is ALOT of food.  Food that keeps all winter long. Finally, we are vegetarians so we needs our protein.  Add in the soup beans.  25 bushels per acre is typical @ 60#’s a bushel.  Again, cut in half for polyculture and you get 12 bushels of beans, or 720 pounds.  So to recap our acre is now growing enough seed to produce 50 gallons of oil, 18000#’s of squash and 700#’s of dry beans –both of which keep for months and months.  That is rather good.   Lets make it better!

Remember the thought stream that got me to this point over my now cold steel cut oats.  Chopping down cellulose rich tall plants for methane fuel stock and compost.  25,000 8′ tall sunflowers…. lay them down end to end and its over 37 miles.  I haven’t weighed one, but figure they weigh 5#’s each.  That is 62 tons of green material that is going to be pretty close to perfect C:N ratio by harvest time.  125,000#’s of material – composted down with a 75% loss gets you to about 30,000#’s of compost, or 55 yards.  That seems high so I would love to prove the math.  That is enough to spread the entire acre with .4″ of compost- a very healthy amount and far more than I apply annually in my market gardens.  Fertility would increase to say the least.  62 tons of material would also be enough to build 8 Methane Middens so that we can heat our winter greenhouses or the chicken barn.  Dang sucka.

Back to the fuel part again.  50 gallons doesn’t sound like much.  And it isn’t.  Most of us only get 22 mpg and  drive 12000 miles per car per year – 540 gallons per year per car.  Ouch.  But we all know that we will drive ALOT less in the future and most cars are fuel hogs.  My VW TDI gets 42 MPG towing a 1000# of cargo in my trailer.  Have I mentioned I love my car?  So, even saving 5 gallons for the Grillo to till the acre, we still have enough oil to drive over 1750 miles towing all those squash and bushels of beans to market.    If we relocalize that is 175 round trips to town 5 miles away – 3 trips a week. Huh.

But I want to re-stress my loathing of the food v. fuel argument.  It is a farce if you think it through and know the science of biofuels-even ADM fed their ethanol mash to tilapia.  So we take the 25,000 sunflowers, grind up the seeds (will need some energy there – unless we build a bicycle machine to do it), and press them.  That seed mash left over from the pressing doesn’t just disappear.  In fact, about 50% of the total oil is essentially impossible to remove from the pressed seeds without solvents, and the protein and carbohydrates are still there too –i.e. the food value of the seeds is still there.  That means you still have 1500#’s of protein rich (40%) meal to feed to your livestock.

Can we rebuild the next 20 years to allow us to transition to a less energy dense future?

1 acre nets 18,000#’s of squash, 750#’s of dry beans (4500 cups cooked!), 1500#s of animal feed, 30,000#’s of compost after you have heated your buildings with 8 Methane Middens worth of energy, and you also managed to make enough oil to power the tractor and drive to town 3 times a week for the next year.

On one acre.

Be the Change!

-Rob

Suburban Pollarding: Making your own mulch

There are several themes here on One Straw, but it can all be summed up with the statement that we need to build a regenerative culture as we skip merrily down Energy Descent.  To do that we need to rebuild our culture, grow more of our own foods, find a way to power our civilization, learn a shit ton of new/old skills and stabilize the climate whilst dealing with the next 50+ years of weather silliness and rather a lot more.  Any good permaculturist likes to hit more than one goal with each throw so I have been focusing on biomass lately.

I really need to write a biomass specific essay, but here is the skinny.  Where I live in south central Wisconsin there is only fair solar and wind resources, no geo thermal to speak of and it has been several million years since we had a decent tide.  But, thanks to plentiful rains, if you stop mowing your lawn for a decade you get a nice old field sucession.  They don’t call it the “Northwoods” for nothing; we are really good at growing trees.   Solar is a great way to make electricity and you would be insane to not consider something with such crazy low maintenance needs, but biomass has alot of fringe benefits to offset the labor input.  Primarily – if you do it right you sequester literally tons of carbon.  We all know that is cool ever since Al Gore told us so, but not only can we help offset truly catastrophic climate change, if we do it right, we can also heal our soils to feed our burgeoning billions.  Carbon is a pain in the atmosphere (above 275ppm anyhow), but DAMN is it cool in the soil.  We need to put it back.

Here is one of my all time favorite sustainability facts:

By raising the organic matter content by 1% in the top 6 inches of soil, you have effectively sequestered all the atmospheric carbon above that area of soil.

Dang, sucka! This is why agriculture is such a huge contributor to global climate change – conventional ag destroys organic matter, removing it from the soil and getting it airborne through massive nitrogen fertilizers and tilling. But the simply beautiful thing is that we NEED to raise the organic matter content of our soil by 2-5% everywhere if we want to produce food organically and by doing so we heal the atmosphere.  Trees, woody stalks, and straw are the best ways to get carbon out of the atmosphere (plants do it for free and are, by nature, carbon negative).  The trick is to harvest that biomass efficiently and then process it in such a way as to sequester it for the mid/long term.  Enter my Tuesday project.

I live right on a freeway.  In addition to the noise and pollution, the salt spray in the winters also have a tendency to kill off or stunt just about anything I have planted there (trying siberian pea shrubs).  But buckthorn thrives.  Now I would never intentionally plant buckthorn, but there are several specimens on the D.O.T. side of the fence and one mature one just on my side.  I have left it up as a windbreak to protect a maple I have planted.  But that buckthorn is rather vigorous, as is their wont, and needs to be hacked back every few years.  We call it trimming when its a chore and the material is thrown away, but when it is done with the specific goal of harvesting the biomass the proper name is Pollarding.

Here is a shot of the buckthorn with about 20% of the south side of it pollarded.

Its a BIG buckthorn! Pulled about 80#'s of biomass out and you can barely tell.

I essentially limbed up everything I could reach that had limbs facing in the 30 degree arc around the maple.  This freed up a lot of room, and made too big piles of material.  I separated these by use – the larger diameter wood (.75″-3″) I intended to chip up for oyster mushroom growing media, the leafy material at the end of the limbs would be shredded for compost.

the left pile is half off frame and is intended for compost, the right is about 10' long and intended for mushroom media.

I did not put any of this down as mulch due to the presence of very green berries on the tree.  By composting this material I will essentially sequester half the carbon from the tree (the rest is off gassed by bacteria) for 5-50+ years in the soil as humus which is pretty stable.  The results of chipping are always mind boggling.  What started as enough material to fill my dump truck bed (11 cu yards) I am left with about 2-3 cu feet of wood chips and perhaps 9 cu ft of green shredded branches that will compost down significantly.  Total weight was roughly 100#’s.

Chips in foreground for mushroom growing, green shredded material in background for compost.  Entropy!

After composting it will be about 15# once the water is consumed by the bacteria and half the material is off gassed.   The chipper does use fuel, but this stunt only consumed about 1/2 a cup which is less than my neighbor used mowing his lawn while I did this.  Larger chippers are more efficient and can be run on methane from the midden or ethanol if gasoline engined, or biodiesel if not.

The shear scope of our problem can be staggering at times.  I would like to add 1″ of topsoil to my new garden, which is 1100 sq ft.  That works out to just shy of 7000#’s of compost.   For one garden.  That is why I am becoming more and more convinced that the single most important thing we can do is to plant trees.  LOTS of trees.  The great thing is that it isn’t that hard.  1.5 acres of willow will produce 22000#’s of chips annually (harvesting .5 acres a yr) for 2 decades or more before needing to be replanted.  And that is dry trunk chips only, not the leafy biomass of the fronds.   While we can’t grow the biomass needed to heal our soils in our own backyards, we can certainly plant enough trees and “woody” plants into our home landscapes to maintain the soils once we have healed them.  100 acres of marginal corn land – say near rivers that flood seasonally and shouldn’t be planted to annuals anyhow- planted to willow coppice would produce enough biomass to rebuild almost 100,000 sq ft of garden a year.  Every year after year 3.  In 8 years we could have a garden as large as mine in every yard in my hometown of 500 homes churning along at 5%+ organic matter  and be producing 500,000#’s of food annually while also sequestering hundreds of tons of carbon annually.

When combined with energy systems like the Methane Midden, which has 6000#’s of chips in it, sequestering carbon can also offset carbon emissions for energy production.  I planted 15 willows on our property this year specifically to begin coppicing in a few years.  Next year I will pull rods from them to start 50 or so more.  Box elders are another strong coppice candidate in this area.   The hedgerows for a 5 acre sustainable produce farm divided into 1 acre plots would grow enough biomass to run a gasifier for a year while sequestering 11000#’s of carbon to be added back to the fields as biochar to help create terra preta.

We can partner with nature to heal the damage we have done.  Even in the burbs.

Be the change!

-Rob

%d bloggers like this: