Healthy soil and sustainable growing

[Keith Addison <gha@journeytoforever.org>]

Hello Paul

Maybe I can bring it back to building soil, I'll try.

> Well, I can't keep spending my own time on the biogas business, 
> because it's not about building soil or growing in it - which is 
> what I intended the list for.  I haven't touched on the other 
> obvious problems with it, and why more people aren't taking it 
> seriously as a home energy alternative.  It has to be used as it's 
> produced, which is awfully inconvenient, or else pressurized for 
> temporary (at least) storage which requires energy to pressurize and 
> costs more money for pressure tanks.  Sorry but New Alchemy still 
> raises more questions than they answer, so I don't have time for 
> them.  And poor John Fry in Santa Barbara simply forgot to factor in 
> the cost of his own labor (and equipment - did he use a loader?) for 
> feeding manure to the digester every day for six years.  He 
> conveniently left out any figures on what he lost by not using it as 
> it was produced, or if he pressurized it for storage what it cost 
> for the added equipment and cost of pressurizing.  And I can't help 
> won
> dering, what did he do with all that gas in the summer in Santa 
> Barbara? Make speeches about biogas?

:-) Somebody who met John Fry there told me he was a "sweet soul".

John Fry retired to Santa Barbara, but he did his work with pig 
manure in Johannesburg, South Africa. He used the biogas as fuel for 
a 13 hp diesel generator. You can store the gas in tractor or truck 
inner tubes, among other ways, or like Jean Pain did it in France. 
The book Fry wrote has quite a lot of information on applying the 
sludge to the land, but I don't agree with him about that.

The book is online here, if anyone is interested:

"Methane Digesters For Fuel Gas and Fertilizer, With Complete 
Instructions For Two Working Models" by L. John Fry
http://journeytoforever.org/farm_library.html#methanefry

With biogas sludge the pathogen cut-off that you get with 
thermophylic composting isn't there, which has been a reason for 
people working in developing countries to abandon the biogas option. 
But if they'd composted it first it would have been okay.

It's a one-sided question whether or not biogas sludge has high 
levels of "nutrients". Chemical farming is all about plant nutrients 
(accompanied by pesticides) but soil building isn't all about plant 
nutrients, even if the nutrients are "organic". It's a biological 
matter, not a chemical one, or not only a chemical one, and it turns 
out that what's best for the plant is what's good for the soil life, 
the "farmer's invisible labour force".

Someone who thinks biogas sludge is a "great organic fertiliser" 
should try feeding it to red manure worms, or sprouting some water 
cress seeds in it, which is the classic test for finished compost. 
Anaerobically digested sludge is polluted with phytotoxins (plant 
poisons), volatile organic acids and so on, which water cress seeds 
are particularly sensitive to. See, eg:
http://www.magicsoil.com/preventi1.htm
VFA's

I had a discussion about biogas sludge at SANET a while back with 
people including Elaine Ingham (SoilfoodWeb). The upshot is that 
sludge must be composted first. Then the high N content is at least 
useful as you can use a lot of high-C material and still be within 
the C:N ratio limits, and "browns" are usually more readily available 
than "greens". No more pathogens or phytotoxins. There's an added 
energy benefit to go with the gas since hot composting can also 
provide a usable form of heat via a heat exchanger, if you need it.

As for N content itself, if compost is made well it usually ends up 
with more N than it started with, but it might not matter. Studies 
comparing different composts have found that compost with lower N 
content can give better yields than compost with more N. Not 
necessarily so, it can be the other way round too, but NPK isn't all. 
As we all know. If a farmer's worried about N he's probably worrying 
about the wrong things.

I don't think John Fry (and others) are lying about the results they 
get with biogas sludge, it's just not the whole story. It reminds me 
of Albert Howard's quest to reform the European manure heap, which 
the farmers mucked out and used as fertiliser after the cattle had 
spent six months or so adding to it, peeing on it and trampling all 
the air out of it, smelly, sticky stuff. One study found it took the 
soil life two years to recover. The plants grew though, lots of 
nutrients to pump them up, and everything didn't just collapse and 
die because the soil was already quite fertile with quite good humus 
levels due to other farming practices. A fertile field can take it. I 
saw a field covered with dead worms the day after it had been treated 
with sludge from a piggery. The field survived and the crops grew, 
but quality and pest-resistance are not enhanced by destroying the 
soil life, no matter how much NPK you might be adding.

European farmers still do it that way. Ah, the fresh smell of spring 
in Amsterdam, when the surrounding farms start mucking out their 
cowsheds and the city's small enough that the whole place stinks. If 
it stinks, don't use it!

Somebody's just been talking about compost at the Biofuel list (it's 
a regular topic there). "Countless tons of compost over the years has 
turned shallow hard-pan clay into beautiful rich soil that takes 
little effort to turn," he said. Here at our small farm in Japan I'm 
currently having my fourth experience of how well that works with 
shallow hard-pan clay - very well, and it doesn't take years. Biogas 
sludge won't do that for you if the soil's in poor shape. It's not a 
fertiliser, it's just a raw material for making real fertiliser.

John Fry had a 25-acre farm and a thousand pigs producing two tons of 
wet manure a day. Before he started making biogas with it, he says 
"For years I composted it and spread it inches thick over the farm 
and used a rotary hoe to chop it into the soil." His soil was already 
fertile when he started using the biogas sludge on it.

Of course it depends on the circumstances, but generally I think 
there's room for a biogas digester on a small farm or smallholding, 
it's probably worth investigating.

Elsewhere there are other issues, like the indoor woodsmoke problem 
with woodfire cooking, and/or lack of firewood, which often comes 
with soil erosion. The Nepalese installed 100,000 locally designed 
household-scale biogas digesters in 10 years and wanted another half 
million, but with this biogas system and many others the sludge is 
composted before it's used on the land. Then it makes sense. I wonder 
how many Nepalese families are making compost now purely as a result 
of having biogas digesters.

Best wishes

Keith Addison
Journey to Forever
KYOTO Pref., Japan
http://journeytoforever.org/



> paul, tradingpost@riseup.net
> ---------------
> The care of the Earth is our most ancient and most worthy, and after 
> all our most pleasing responsibility. To cherish what remains of it 
> and to foster its renewal is our only hope.
>   - Wendell Berry
> *********** REPLY SEPARATOR  ***********
>
> On 4/28/2006 at 5:56 PM Greg and April wrote:
>
> >The carbon came from the wood chips.
> >
> >When I was saying chips, I wasn't talking about chunks, but, something
> >more
> >along 1/2-3/4 inch max.    Shreds might have been a better term.
> >
> >You can look up the data that New Alchemy used ( they have 69 references,
> >but I'll just give a few ):
> >
> >Compost:
> >
> >Poincelot R.    1972
> >The Biochemistry and Methodogy of Composting.
> >Connecticut Agriculture Experiment Station
> >Bulletin 727    March 1972
> >New Haven Conn
> >
> >Digested Manure:
> >
> >Hog:
> >Taiganides, Eliseos P. 1963
> >Characteristics and Treatment of Wastes from a Confinement Hog Production
> >Unit
> >PhD dissertation, Iowa State Univ.
> >Science and Technology, Agriculture Engineering.
> >Available from University Microfilm Inc.
> >An Arbor Mich #63-5200 ( 177 pg )
> >
> >Cow:
> >Hart, Samuel    1960
> >Sludge Digestion Tests of Livestock Manures
> >Dept. Agr. Engr. Univ. of Calif. Davis
> >Offprint manuscript.
> >
> >The amount of methane generated is based on several factors including
> >waste
> >material used ( even manure from different animal types can vary the
> >amount ), the temperature, the time in the unit, and even the amount of
> >dissolved solids in the slurry ( since it's the dissolved solids that
> >actually do the job ).
> >
> >
> >Costs to build units vary, with such things as the materials used.
> >Smaller units can be built from scrap 55 gal barrels that can be had for
> >free, if you know where to look.    They can be made from concrete if that
> >is your style and your budget    I built one out of a 3 gal pickle jar,
> >when
> >in high school, just to see if it would work, using dog manure ( from when
> >the neighbors dog would go in our yard ) and it did.
> >
> >
> >Some rough figures.
> >(from Methane Digesters for Fuel Gas and Fertilizer )
> >
> >Cattle manure
> >100%    1.4 cu Ft ( per lb of Volatile Solids)  65% CH4
> >
> >Chicken manure
> >100%    5 cu Ft    59%
> >
> >Chicken manure /
> >paper pulp
> >31%/69%    7.8 cu Ft    60%
> >
> >Chicken manure /
> >grass clippings
> >50%/50%    5.9 cu Ft    68%
> >
> >( from Hand Book on Bio Gas and It's Applications )
> >4 cattle ( as we can see above they are not the best source ) and a 5 cu m
> >( 177 cu Ft ) gas unit, and retain for 50 days you will be producing 1.55
> >cu
> >m of gas @ 20*C ( 54.7 cu Ft @  68* F ) every day.
> >
> >How long it takes to repay initial investment is highly dependant on the
> >amount invested, and what the gas is worth to the person using it.
> >
> >The digester built by John Fry ( that I mentioned a month or so ago ) on
> >his
> >hog farm ( average 1000 hogs ), cost him about $10,000 to build, and
> >produced 8000 cu ft of bio gas a day ( 4,680 BTU's a day ).    His figures
> >showed that this was worth $7.57 a day in Santa Barbara Cal. in 1973, or
> >$16,578 in 6 years just for the gas alone, and not for any fertilizer
> >value.
> >So his return of investment, was less than 6 years.
> >
> >Another way to look at it:
> >
> >Average cost per Hog to build: $10
> >Average amount of Bio gas per hog: 8 cu ft a day
> >Average number of BTU's per hog: 4.68 each day
> >Amount of liquid fertalizer: Approximately 500 gal every 3-4 days ( 125 -
> >170 gal / day ) - for an average of 1000 hogs.
> >
> >As mentioned above, even as few as 4 cattle can produce 54 cu ft of bio
> >gas
> >each day, and used effectively, that is enough to provide supplemental CO2
> >and keep a green house warm on chilly nights.
> >
> >It all comes down to how people apply the resources that are available.
> >Let manure do nothing over fall and winter, or use it to heat a greenhouse
> >in winter that might otherwise go unheated.    What is the value of
> >growing
> >cool crops in the middle of winter in the green house?    That is
> >something
> >that people will have to figure out and decide for themselves.    Is there
> >value in fresh out of season crops?    If so how much?
> >
> >Every week I meet people that say " I didn't know that " or " I thought
> >you
> >couldn't ... "
> >
> >Personaly, I think the problem with digesters is, people don't try because
> >they thought they couldn't ....    Until more people do try, we will never
> >know for sure.
> >
> >Many people still think that cars can only run on something that comes out
> >of the fuel pump at the gas station, and don't think that they can make it
> >them selves, because that is what they are used to thinking ( not to
> >mention
> >brainwashing ).