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Re: [SANET-MG] Fw: [USCC] organic matter stability
--- Frank L Teuton <fteuton@SYMPATICO.CA> wrote:
> Forwarded with permission, please CC Bill with replies;
> ----- Original Message -----
> From: "William (Bill) Carter" <WCARTER@tceq.state.tx.us>
> To: <firstname.lastname@example.org>
> Sent: Thursday, August 05, 2004 11:55 AM
> Subject: [USCC] organic matter stability
> At a presentation in Austin last week, an NRCS representative said that the
> residual organic matter in soil is 90% humus and that it has an average loss
> rate of 3% a year.
"Humus" is a poorly defined term. All living organisms are composed of unique arrays of
molecules assembled over their lifetimes. The "decay process" involves widely varied
decomposer organisms arrayed with their own unique arrays of digestive enzymes or
gene-toolkits able to deconstruct and recycle molecules or their constituent elements.
The most popular molecules, simple starches and sugars, are devoured by a larger number
of decomposers, and some organic molecules are far less popular. Humus will end up
being mostly composed of the least digestible molecules which take the longest to
deconstruct. Therefore, it will remain in the soil largely unchanged for the longest
period of time.
> In contrast, the organic matter in raw crop residues have
> a first-year loss rate of about 50%.
Fresh crop residues have a large proportion of easily digestible molecules, and
therefore support large population explosions of soil decomposers. The transformations
from one decomposed lifeform to another living one does not exhaust critical
nutritional molecules -- the loss is mainly in the form of respired CO2 gas which is
endlessly replenishable. Eventually the decomposers are in turn decomposed.
> Thus the common soil science statements
> about how long it takes to build up soil organic matter levels.
People who don't want to break out a sweat thinking about the actual processes of
decomposition might well be content with simple over-view statements which have very
little information content. Knowing "humus" percentages" or "organic matter"
percentages does not provide much actual information content. It is far more
informative to have identification of the populations of the decomposer microherd
operatives, as that gives some information of what to add or what to scale back on
which can benefit the choices of crops which one seeks to maximize.
Some domesticated crops have a forest origin and are evolved to enjoy a fungal
dominated soil, 90% fungal dominance of soil biomass, versus some plants are evolved
from grasslands with less than 50% soil fungi biomass constituants. In general, to
promote fungal dominance one would increase the ratio of carbon content of cellulose
and lignins which fungi have more genes to decompose. By biasing the soil to have less
fungal life one might be promoting predatory lifeforms hostile to the crop, leading to
increased disease susceptability, decreased root efficiency, other impairments.
Asking people to study the history of their crops is not part of the lore of soil
management. Give them some simple rules of thumb and simple tests and they are happy,
never quite realizing that they don't know a lot more than before.
> When I asked
> whether incorporation of compost into soil affects the loss rate of its OM,
> he surprisingly said he thought the reverse would be true -- possibly more
> with regard to how tilling affects soil oxygenation and respiration than
> with the effect of partially burying the compost to reduce its exposure to
Compost mulch has mixed blessings, serving as nesting cover for some pest insects but
also has numerous benefits. Aerial watering, as in rainfall or sprinking, has an
oxygen-starving action by pasting the soil surface into hard crusts. Mulch protects the
soil from the impacts and keeps it from dehydrating rapidly. Moist organic material in
contact with soil will of course be devoured more rapidly than dried OM under a crusted
soil, but where are the advantages of reduced digestion? Inedible nuggets of OM might
as well be stones. Microherd actors eat and excrete. Their micro-manures are digestate
that plants can use as readily as the disintergrated plant debris, and often times the
plants can more readily absorb such predigested water soluable micro-manures.
> This led me to ponder the typical organic matter specifications for compost.
> They generally only look at total OM, whether it is 90% humus or raw
> vegetative debris (but presumably somewhere in between). I've generally
> thought that the organic matter contributed by compost could be considered
> to immediately become part of the soil organic matter content. But the
> compost's organic matter will be lost at a rate faster than 3% in the first
> year, although one would hope less than 50% in the first year.
Wide experience has shown that more like 60% of compost is consumed in the first year.
The goal of feeding the soil is to feed the plants, not build up an ever enlarging
hoard of buried compost. The humus residue of the most indigestible organic molecules
has assorted values beyond plant and microherd nutrition. There is a net buffering
effect of the assorted charges of electrons poking out the sides of molecules which
affect to cation exchange capacity of the soil. There is the habitat value of
slow-release nutrients. Crumb structures are partly the result of exudates of microbial
colonies that paste grains together and form the pore sizes of the soil, and humus is
involved in that total habitat construction.
Life knows what it is doing -- it has 3.7 bilion years experience on the job training.
Plants evolved onto soil microbe turf, and are well adapted to it.
> Stability measured through respirometry should give some indication of where
> the product is within this range of loss rates. How well can we predict
> those rates, though? Should we assume that there is no significant
> difference in the loss rate or decay rate of the organic matter in any
> compost meeting minimum stability requirements?
With over 10,000,000,000 microbes per teaspoon of dry soil, and some 5,000 different
species (most unknown to science) working that teaspoon, it is premature to evaluate
respiration levels in any meaningful way. Some microbes only spring out of their
low-respiration hibernation when the pH gets at some exact level, others wait until
some chemical cue from their prey is detected. If you want some nice scientific
measurements to make you happy, go for beating the 1,488 pounds of tomatoes from four
plants listed in the Guiness Book of Records. Use lots and lots of compost
top-dressing, as per the instructions of the winning title-holder's book. The winner of
the largest pumpkin has similar advice in his book.
> Humic and fulvic acids seem to remain somewhat mysterious although we seem
> to be confident of their importance and unique functions in the soil
> environment. The TMECC method for determining humic & fulvic acid content is
> "proposed" and apparently little used. Standard cooperative extension soil
> tests rarely if ever address it. Should we assume that the humic/fulvic
> content of all stable composts is equivalent, or unimportant? Or should we
> be moving toward testing and specifying for it?
Acids of any kinds have a detrimental effect on some elements, locking them up, and a
beneficial effect on other elements, causing their release. In general, well composted
living soils tend to remain close to neutral regardless of the widely varying elemental
mineral compositions. Measurements of dead things are highly misleading. Plants can
generate (mild) electrical charges at their roots which can jerk loose lightly bound
molecules which would not be considered "freely available" by testing dead soil.
Most of the tests of soil nutrient levels have some deceptive biases: Nitrogen levels
are tested by killing everything and counting the free nitrogen gas that can be driven
out of the soil under dire measures. It does not tell you anything about the
nitrogen-fixing over time by living organisms with nitrogenase genes. A soil alive with
nitrogen-fixers will have more nitrogen over a season than can be measured at any
instant in time.
A large body of disinformation is endlessly repeated which underestimates nitrogen
availability from natural sources and steers customers to buying overmuch quantities
from nitrogen salesmen. The end of this idiocy is the 150 dead zones that have appeared
around the world near the outlets of over-fertized rivers carrying away unused nitrogen
fertilizers. The number of dead zones has doubled since 1990.
Every year of so it is necessary to repost links to the article by Roland Bunch
summarizing the still-not-translated-into-english results of over 2,000 farmsites using
the concept "The Ecological Management of Soils".
Weapons-grade Nitrate makers depend on subsidies from farmers to keep their global
munitions businesses going. They are killers, by definition, and one should expect that
lying is considered a sin too minor to be bothered to notice they are doing it. Their
lies and large profits have steered public discussion towards dead research, which
benefits them, and has paid for smears on organics which discourages research on living
soil systems. Do you need a reminder of what "weapons-grade" nitrates means? Murrah
building, Oklahoma City, fuel oil and sacks of ammonium nitrate mixed together.
Killers would prefer that the discussions stayed on their terms, measures of dead
things, never accounting for the power of living systems dynamics.
Here is some dossiers of the corrupt use of wealth by Killers Kochs, Koch Industries,
Koch Oil, Koch Fertilizers, as a specimen of the typical weapons-grade nitrate
industries who lie about organics with millions of dollars worth of full-time employees
in an empire of propaganda mills:
> Thanks for any comments on these questions.
> Bill Carter
> Watershed Management Team MC 147
> Texas Commission on Environmental Quality
> P.O. Box 13087
> Austin, TX 78711-3087
> Phone: 512-239-6771
> Fax: 512-239-4410
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Sincerely, Lion Kuntz
Santa Rosa, California, USA
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