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Re: Humus -- rural -> urban -> rural
Thomas Hansmeyer poses the question we all need to ask, namely:
> [snip] ... I guess I am asking if the Luebkes
>needed to import Carbon from other sources? Which gets into further debate
>as to whether enough carbon exists within the current system to allow all
>of agriculture to increase the OM to healthy levels, 5% or so.
Composting is fine, and avoids lots of problems that have regulations tied
to them, but actually, it's even better if the composting occurs in the
soil. Lots of benefits are lost in having the composting first as a
"treatment" of the organic materials in order then to produce a soil
amendment. The microbes in the compost pile are also needed in the soil.
Another case in point is with the use of urban sewage. We call it "waste"
and much is sent to the landfill. If we called it a "resource" we'd be
working on improving the quality, and thereby reduce some of the
potentially harmful components of organic and inorganic types. Even the
legally required anaerobic digestion could be avoided if society was
properly aligned with the needs of recycling the carbon, as Thomas
Hansmeyer mentioned in his post, where the carbon is food supplied to the
microbes and other "soil" organisms like dung beetles. As it stands, some
sewage (or treated, "biosolids") is fine for land application, before or
after composting, and other sources are fine in certain soils -- as for
example, alkaline soils when there are somewhat more heavy metal components
in the sewage (or biosolids) than one would use in an acid soil. However,
there is a strong engineering perspective (bias) in the treatment and use
of such resources, and there are ecologically sound alternative
perspectives we need to begin using.
I have not done the calculations on how it all adds up, but as a matter of
principle, there needs to be a complete cycle of organics (and inorganics
also) leaving the land where food is produced and its return from the areas
where it is used in foodstuffs (whether eaten first, or discarded uneaten),
building materials, clothes, or whatever. That is, it is not a negative
feature to bring materials "back" to the land from "outside". It's all one
system, and should include the urban part along with the rural part.
On another "curiosity info" note, there is a rumbling in our current
Legislature that one should not label compost as a "fertilizer" or a "plant
nutrient", but as a soil conditioner/additive. This is from the commercial
fertilizer interests, who don't acknowledge that the NPK of commercial
fertilizer does little good (or should be) for feeding the microbes, which
in turn feed the higher plants AND condition the soil. If we reacted as
strongly against some commercial fertilizers with regard to "heavy metals"
(including "trace minerals") as we do when they are in the sewage, we'd
likely be banning the "fertilizer" to the landfills and bagging the sewage!
;-)
Cheers,
R. H. (Dick) Richardson Office: 512-471-4128
Zoology Dept. Home: 512-476-5131
Univ. of Texas FAX: 512-471-9651
Austin, TX 78712