[permaculture] rock dust - is it really necessary?

nepal nepal.roade at googlemail.com
Thu Feb 19 17:33:22 EST 2009

On Thu, 19 Feb 2009 12:41:39 -0800 (PST)
"Jordan Fink" <jordan at riseup.net> wrote:

> i have to ask the question here- is rock dust really necessary for any
> permaculture site.

AFAIU, it won't do any harm.

Have you read "The Survival of Civilisation" by John D. Hamaker and
Donald A. Weaver? (this is the primary work on rockdust)
> Dr. Elaine Ingham of Soil Food Web is saying that the evidence
> suggests that all soils on earth have plenty of all necessary
> nutrients to grow healthy food. 

I'd like to know what that evidence is as all I've read and by
experience it is not the case.

> Many soils, however, don't have a
> healthy soil food web which means that all that nutrion is
> biologically unavailable. 

Which is the perfect situation for rockdust application as its primary
benefit is to the soil culture. 

> The application of organic fertilizers and
> rock dusts just adds a little bit more soluble nutrients but doesn't
> improve the soil biota's own capacity to unlock the recourses already
> available.

Rockdust is not a fertiliser and it does directly affect the soil
organisms, *significantly benefits* in fact. This I have read about and
confirmed by practical applications. You obviously have not read
Hamaker (or any other source on rockdust) in making such statements. 

> A few well-designed applications of compost teach will have better
> results, cost far far less and you don't have to justify supporting
> dredging and mining.
> -jordan

Not true. Composting is a short term solution to returning minerals
via humus to the soil. Whatever minerals or trace elements that were
*not* available to those plants will not magically appear when they
return to the soil as compost. Minerals and trace elements get used up.

I accept your point about dredging and mining, neither of which are
sustainable. However rockdust is an already existing waste product from
mining which already exists in significantly large amounts that could be
put to use.

Bottom line on this, a brix meter will confirm (or not)
the value of rockdust treatment with regards to nutrient density.


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