[USCC] Tire chips

[Chaney, Rufus]

Dear USCC:

I have commented before that the Zn added from tire chips is
undesireable in composts. In acidic soils, that Zn become plant
available over time as the rubber is degraded by microbes. Further, tire
chips don't absorb much water from the feedstocks, so they mostly give a
surface for the feedstock to spread out on during composting. The chips
may last longer than wood chips, but they do degrade over time and Zn
enters the compost. Even with biosolids composting with low metal
biosolids (Higgens et al., 1986), composting with rubber tire chips
doubled compost Zn.

In areas with Zn deficiency soils, rubber might be a resource to serve
as a low grade Zn fertilizer. Our testing has shown that even ground
rubber has have time to be degraded to release the Zn to the soil before
it is taken up by plants.

So, with the exception of producing a high Zn compost for Zn deficient
soils, I cannot recommend use of tire chips for composting anything.

A web search will identify many negative opinions about rubber use. I
have seen many reports about severe Zn phytotoxicity where tires were
used to burn out tree stumps, etc. The Zn does not disappear. Whether
the PAH compounds in the rubber are a special danger is arguable, and
PAHs are a natural part of most organic resources formed by microbes.

Regards,

Rufus Chaney
Beltsville, MD

-----Original Message-----
From: compost-bounces at mailman.cloudnet.com
[mailto:compost-bounces at mailman.cloudnet.com] On Behalf Of Scott Reil
Sent: Tuesday, July 01, 2008 1:40 PM
To: 'Compost Discussion List'
Subject: Re: [USCC] Tire chips

I've heard nothing good on rubber breaking down and plenty of bad
news...

http://www.puyallup.wsu.edu/~Linda%20Chalker-Scott/Horticultural%20Myths
_fil
es/Myths/Rubber%20mulch.pdf

Chemicals from the vulcanization process can include:

Sulfur - cross-linking agent
Zinc Oxide - activator
Zinc Dibutyldithiocarbamate - accelerator
Zinc Diethyldithiocarbamate - accelerator
Zinc Mercaptobenzothiazole - accelerator
Titanium Dioxide - whitening pigment
Calcium Carbonate - anti-tack agent
Calcium Nitrate - coagulant
Corn Starch - donning agent
Potassium Hydroxide - pH stabilizer
Anti-oxidants, anti-foaming agents, anti-webbing agents, surfactants,
color
pigments, flavoring compounds, fragrance
and other additives used are mixtures of compounds that are proprietary
knowledge and rights of the various brand
owners and may not be disclosed here.

I find the inclusion of carbamates to be particularly notable as they
are
getting as lot of bad press as pesticides (nerve agents). As noted in
the
above article, as much as 2% of the tire mass can be zinc, a lot higher
than
the 4-6 ppm we like to see in soils...not a good idea from where I sit
AT
ALL...


Scott Reil
Safe Lawns and Landscapes LLC
70 Highland Park Drive
Bloomfield CT 06002
860-243-8733



-----Original Message-----
From: compost-bounces at mailman.cloudnet.com
[mailto:compost-bounces at mailman.cloudnet.com] On Behalf Of John P Kelly
Sent: Monday, June 30, 2008 3:20 PM
To: compost at mailman.cloudnet.com
Subject: [USCC] Tire chips

Composters:

I am interested in hearing from composters who have experience with tire
chips as an alternative bulking agent.

John Kelly
New England Organics
Director of Product Sales
135 Presumpscot Street, Unit 1
Portland, ME  04103
1-877-4-COMPOST
207-347-3605
207-781-5794 fax
207-650-5010 cell
www.earthlifegrows.com



_______________________________________
Join us at the US Composting Council's 17th Annual Conference & Trade
Show
January 26-29th, 2009 at the Westin Galleria in Houston, TX.
The National forum for those involved in the development and expansion
of the composting and organics recycling industry.
Conference Highlights, Registration forms, Exhibitor information and
Sponsorship Opportunities available at the USCC website:
www.compostingcouncil.org or call the USCC at 631.737.4931 
________________________________________________________________________
______
Compost maillist - compost at mailman.cloudnet.com
http://mailman.cloudnet.com/mailman/listinfo/compost
_______________________________________
This list is a service provided by the US Composting Council (USCC).
(c) Copyright 2004 United States Composting Council - All rights
reserved

Opinions expressed do not necessarily represent the USCC, the
Foundation, or the Board of Directors.

Non-members of USCC are encouraged to join the Council through its
website at: http://www.compostingcouncil.org/membership.cfm

Members posting CC copies to the list and other addresses may have their
posting privileges suspended. 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 unsubcribing or to report bugs and problems, send
a message to the List Manager at
compostlistmanager at compostingcouncil.org