Subject: Re: Purity Of Organic Foods/Compost

From: Elaine Ingham <[email-masked]>
Date: Sun, 24 Nov 2002 08:51:47 EST

Luckily, when you take leaves contaminated with who-knows-what pesticide and
compost them, letting the microorganisms do their thing, the microbes chew up
the pesticides, turning them into carbon dioxide, water, more microbial
biomass and some waste materials that are then used by other microbes.

The important thing is to make sure you maximize the DIVERSITY of microbes in
your compost, so you are most likely to have the microbes needed to chew up
the pesticides.   You also need a diversity of food resources, that is, kinds
of organic matter, so you have the diversity of foods that the diverse set of
microbes need to do their jobs.

The more diverse, the more likely you will get decomposition of toxic
chemicals.  We're talking diversity of BOTH plant material and microbes here.
 And a couple more things are needed....

Typically you need some temperature in your compost pile so the microbes have
the energy to decompose the difficult chemical structures of pesticides.  All
those chlorines and bromines and benzene rings in most pesticides require
production of seriously high-energy-requiring enzymes to allow break-down of
the pesticide.

But that's the right amount of heat - not too much, not too little.  If you
see "compost" that has turned black, the composter fried the most important
critters, and the pesticides are probably still present.  Compost is supposed
to be dark brown, not black.  Nor do the pesticides generally decompose if
the compost turns anaerobic.  So, stinky, smelly compost is not compost.  If
it smells bad, it means something is not right.  Don't put it around your
plants.  Learn what is a bad odor, versus a soil smell.   You may need a
course in composting from someone who knows something about these smells and
what they mean.

So, you have to have water and air correct in your pile.  More "not-too-much,
not-too-little" factors.  We need air and water just right - the Goldilocks
principle.  Compost is not a simple linear system, multiple factors have to
be correct all at the same time.  Water influences the amount of air present.
 Too wet, and you go anaerobic.  Too dry, and the microbes are sound asleep.
Must get it just right.
-----
Heavy metals may be sequestered, or tied up in organic forms in compost, in
forms that all but the most destructive chemical analysis will not detect.
Heavy metals stay plant-not-available if you maintain the organic matter
level in your soil.  You lose organic matter in your soil most rapidly when
you plow or physically disturb soil.  Minimize tillage, and you minimize
organic matter loss.  Maintain organic matter, and heavy metals remain
immobile and not-plant-available.

Does that mean you should never till?  I said, minimize tillage.  Till to the
least extent possible.  Vern Cole and Bobby Brock have both shown this to be
the case, along with quite a number of researchers that followed on their
leads.  Minimize tillage.

Residues left in your field in the fall should be decomposed by the microbes,
not sliced and diced and plowed into the soil.  If your residues do not
"disappear", there's something wrong with the set of microbes in your soil,
and you need to fix them and get them working for you again.  If you till
residues into the soil, they may just produce plant-toxic compounds if they
decompose without enough air in compacted soil.

But back to pesticides in compost.  We have a recent addition to the
herbicide world that apparently does not decompose during the composting
process.  Chlopyralid is a serious problem, and this chemical should be
banned from ever being put on another ecosystem.  Nothing decomposes it, and
once you put it on your lawn, you will not be able to convert that lawn into
a vegetable garden or into broad leaf plant production.  I'm rooting for the
little critters, however, and hoping that somewhere, someone will find the
microbe that will decompose chlopyralid.  For more information on the topic,
please look at the City of Seattle's website, and the writings of David
McDonald from Seattle.  I recall that Steve Diver from ATTRA has put together
a good reference list on this topic as well.  Check www.ATTRA.org

To summarize then, to get the decomposition of toxic chemicals in your
compost, you have to have the right microbes, good food for them, correct
air/water mix and additional energy, such as heat, or passage through an
earthworm.  Then, you can feel pretty safe about the "purity" of your
compost.

One last point - In Europe, we almost invariably have to add the right set of
microbes to compost piles, because in most places, the plant material no
longer has the desired set of microbes on the plant material.  In the US, in
the major cities, the same problem occurs quite often.  The plant material
does not contain the necessary set of organisms that decompose pesticides.
An inoculum of beneficial microbes is needed.  Commercial composters find
that adding back a little of the last pile, or adding a commercially
available inoculum of microbes, is necessary.  Add organisms to make sure the
minimum diversity is present.   This says something that should be of concern
to everyone about the wide-spread presence, use and impact of pollutants in
the world.

At Soil Foodweb Inc, we will be offering assays to allow people to determine
whether they have the beneficial organisms in their soil, compost or compost
tea.  The ability to determine presence of beneficial organisms is not
available elsewhere.  Check our website for more information.

Elaine Ingham
President, Soil Foodweb Inc.
www.soilfoodweb.com

---

From: Steve Diver <[email-masked]>
Date: Mon, 25 Nov 2002 19:50:35 -0600

Municipal yard waste consists of grass clippings, leaves,
and shredded tree timmings.

Of these, grass clippings are the only biomass source
with pesticide contamination levels of any concern,
for all practical purposes.

Tree leaves are rarely sprayed with pesticides.  A few tree
species, for example sycamore, will sometimes receive a
fungicide spray to control anthracnose, but that is way back in
early spring.

Shredded branch timmings actually make a valueable compost
feedstock.

Some of the woodier and bulker wood chips provide porosity
and air flow, while the shredded feedstock derived from young
green branches helps balance the C:N ratio; and the lignins from
these young branches may play a role in humification.

Leaf recycling by communities, gardeners, and small farmers
is a great way to generate biomass for use as a mulch and
to make compost.

Leaves are a local biomass source, they are free, and they
are available in large volumes.

Leaves are free spirited and will blow away, though, so that is
why Master Composters talk rounding them up and keeping
them pinned down in a leaf corral.

If you have a 3' x 3' pile of leaves, and one 50-lb
bag of alfalfa pellets (rabbit feed), then you have the
perfect C:N ratio for a thermophyllic compost pile;
just sprinkle rabbit pellets and water as you build the
pile of leaves, then turn after one week to re-mix
and re-moisten the pile.  Repeat the turning process
a few times.  Later, after temperatures are moderate,
you can add worms and let them do their thing, which
adds another biological dimension.

When it comes to organic farms and municipal yardwaste,
in relation to concerns over pesticide contaimination of
grass clippings, an easy solution is to just collect leaves and
branch trimmings in the fall and completely avoid grass
clippings.

Yet when it comes down to mixed yardwastes with grass
clippings and potential herbicide residues, there is good reason
to expect the composting process itself to pack a powerful
punch full of enzymes and microbial bioremediation processes.

Phil Fredericks at EarthCare Technologies, Inc. is the compost
manager who has a lot to say about the compost windrow
functioning as a bioremediation factory.   He uses specialized
microbial inoculants to enhance degradation of hydrocarbons
and waste products handled at his compost facility.  The basis
of this microbial technology goes back to oilfeed research
in Oklahoma in the 1960s.
http://www.ecticompost.com
http://www.ecticompost.com/ec_process.html

Staff at Alberta Agriculture, Food and Rural Development
(AAFRD) developed a database of references on composting
and put this online as:

On-Farm Composting - A Review of the Literature
AAFRD
http://www.agric.gov.ab.ca/sustain/compost/bibliography.html

Included is this topic:

On-Farm Composting: Bioremediation / Soil Remediation
AAFRD
http://www.agric.gov.ab.ca/sustain/compost/bioremediation.html

For a recent literature review on the occurrence, degradation,
and fate of pesticides in composts, see this two-part series in
Compost Science and Utilization.

Occurrence, Degradation, and Fate of Pesticides During
Composting || Part I: Composting, Pesticides, and Pesticide
Degradation (Literature Review)
Fatih Büyüksönmez, Robert Rynk, Thomas F. Hess and
Edward Bechinski
Compost Science and Utilization (1999) | Autumn | Vol. 7, No.4 |
pages 66-82.

Occurence, Degradation, and Fate of Pesticides During
Composting || Part II: Occurence and Fate of Pesticides in
Compost and Composting Systems (Literature Review)
Fatih Büyüksönmez, Robert Rynk, Thomas F. Hess and
Edward Bechinski
Compost Science and Utilization (2000) | Winter | Vol. 8, No. 1 |
pages 61- 81.

See:
Compost Science and Utilization
http://www.jgpress.com/compost.htm

Regards,
Steve Diver

.