Healthy soil and sustainable growing

[yarrow@sfo.com]

At 2:38 PM -0700 5/15/07, Bobby G wrote:
> Speaking of Roundup and other toxins, has anyone
> onlist come across facts about whether composting
> shortens the half-life of this and similar substances?
>  and conversely, does the chemical slow down the
> composting process, by having an effect on microbial
> life?  does compost have a role in remediating this
> kind of toxicity?

Municipal yard-waste composting facilities did some studies when they 
first started operating, and they found that one chemical used on 
lawns, clopyralid, persisted in the finished compost. The composting 
process was able to break down all other pesticides and herbicides 
(the ones that are organic chemicals). As a result of the studies, 
clopyralid was banned in Calif. and a few other states.

Paul Stamets, who wrote the book Mycelium Running (and has an 
informative website), has done studies on growing various types of 
fungi in compost piles for bioremediation. (The U.S. government has 
also done a lot of bioremediation studies.). They found that 
composting does break down diesel fuel and other organic chemicals.

To the microbes, organic chemicals are food.

What composting cannot do is remove elemental toxins, such as lead, 
cadmium, mercury, and arsenic. Rufus Chaney and others have done some 
research on plants that selectively take up and concentrate specific 
minerals and heavy metals, and the last time I checked, some of this 
research was available online. The plants that concentrate toxins 
are, of course, treated as toxic waste and cannot be composted.