Anonymous wrote in
news
an.2004.02.25.23.24.02.154671@notarealserver .com:
On Tue, 24 Feb 2004 12:03:32 -0700, Janice wrote:
Another thing about chemical fertilizers is they only provide what is
put in the bag, what "science" has decided what plants need. Just
like when we buy vitamins, there are only certain vitamins and
minerals added, only those that "science" has decided we need.
Oh, would that were true! The reality is that many of the bagged (dry
granular) fertilizers are industrial by-products from smelting metals.
I did a lot of research into this matter last summer. What I read was
enough to convince me. I no longer have the links so you'll have to
Google for them yourself.
OK.
Search term "slag gardening" turned up 3,250 links including this one:
http://edis.ifas.ufl.edu/BODY-VH019 in which the University of Florida
Cooperative Extension Service Institute of Food and Agricultural Sciences
actually suggest "basic slag" as a source of micro-nutrients for organic
gardeners.
Search term "furnace slag chemical composition" turned this up:
http://www.p2pays.org/ref/13/12842/bfs1.htm which indicates that more than
90% of slag produced "has been used as an aggregate in Portland cement
concrete, asphalt concrete, concrete, asphalt and road bases."
And I also found
http://www.tfhrc.gov/hnr20/recycle/waste/ssa1.htm which
says much the same thing. The tables in these last two showing the
composition of slag makes quite interesting reading.
A search for "smelting waste gardening" and "smelting waste garden" turned
up nothing particularly relevent to this discussion. I did note that just
about all the sites referred to smelting waste as being a hazardous
material. I find it unlikely that environmental protection agencies would
allow hazardous waste to just be "lost" and subsequently turn up in
agricultural products.
SNIP
This is
why the initial application of fertilizers to healthy ground results
in bumper crops ... they are held in the root zone by the humic
compounds until the roots can absorb them.
Ummmm ... further reading that I have done indicates that the reason for
the bumper crops is because fertiliser speeds up the transition of organic
material into humus. Humus contains large amounts of water soluble
nutrients whilst organic material (even after composting) does not hold so
much.
However, failure to
maintain the humus levels results in soil that can't hold the
nutrients in solution for the plants to take up. That means that
increased application levels are needed to maintain acceptable levels
of availability ... and farmers are crying the blues over this one as
fertilizer expenses go through the roof while yields hold steady or
dwindle.
Absolutely! And that brings me back to the point that made me ask the
question regarding factory fertilisers. The emphasis was actually on the
need to maintain good levels of organic matter in the soil whilst the point
was that factory fertilisers increase yield.
That's how I see the organic / inorganic debate.
Chugga
Ivan.