Subject: [SANET-MG] Fw: [USCC] organic matter stability

From: Frank L Teuton <[email-masked]>
Date: Thu, 5 Aug 2004 13:34:48 -0400

Forwarded with permission, please CC Bill with replies;
----- Original Message -----
From: "William (Bill) Carter" <[email-masked]>
To: <[email-masked]>
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. In contrast, the organic matter in raw crop residues have
a first-year loss rate of about 50%. Thus the common soil science statements
about how long it takes to build up soil organic matter levels. When I asked
whether incorporation of compost into soil affects the loss rate of its OM,
he surprisingly said he though 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
oxygen.

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.

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?

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?

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
[email-masked]

_______________________________________________
Compost maillist  -  [email-masked]

This list is a service provided by the US Composting Council.

This month's sponsor of the list is:
Cover-All Building Systems -
Cover-All. buildings are the leading steel-framed, tension-membrane
buildings that are quick to install and offer multiple foundation options to
meet all composting building needs. Each building is constructed with
quality corrosion-resistant steel components and Cover-All's DuraWeave.
fabric membrane cover will never rust, even under the harshest conditions.
Contact 1-800-268-3768 or www.coverall.net

Food Industry Environmental Network (FIEN), a regulatory and policy e-mail
alert service for environmental, food and agricultural industry
professionals.
Contact Jack Cooper 301/384-8287 [email-masked] --- www.fien.com

Renewable Carbon Management, LLC with the containerized, in-vessel NaturTech
Composting System www.composter.com [email-masked]

(c) Copyright 2004 United States Composting Council - All rights reserved
Opinions expressed do not necessarily represent the USCC, the Foundation or
Board of Directors.

Non-members of USCC are encouraged to join the Council through our website
at: http://www.compostingcouncil.org/membership.cfm     For discussion list
policies and information regarding subscribing, unsubscribing, digest or
other options, go to:http://mailman.cloudnet.com/mailman/listinfo/compost

For additional help in unsubscribing or to report bugs and problems, send a
message to the List Manager, Jim McNelly, at [email-masked]

********************************************************
To unsubscribe from SANET-MG:
1- Visit http://lists.sare.org/archives/sanet-mg.html to unsubscribe or;
2- Send a message to <[email-masked]> from the address subscribed to the list. Type "unsubscribe sanet-mg" in the body of the message.

Visit the SANET-MG archives at: http://lists.sare.org/archives/sanet-mg.html
For more information on grants and other resources available through the SARE program, please visit http://www.sare.org.