permed at nor.com.au
permed at nor.com.au
Thu Dec 13 21:10:05 EST 2001
>Aware that information about the ethylene-oxygen cycle taught in
>permaculture courses dated from research carried out in the 1970s, I
>contacted the CSIRO media people in Canberra who tracked down references for
>me. I no longer have these, but locating them should not be a challenge for
>What I found was that there had been no research since the cycle first
Not surprising since the findings have been buried in the archives and
not published (in full) by the Department. Smith's funding was to find a
'cure' for Phytophthora which was wiping out whole Avocado plantations in
Northern NSW. He discovered ethylene in the soil of an organic avocado
farm but not in chemically managed soils so extended his research to
other soil conditions: permanent pasture, recently improved pasture,
cultivated soil, forest soil, recently burnt forest soil etc. He
discovered not only the ethylene-oxygen cycle but how plant exhudates
stimulate microorganism activity to create anaerobic micro sites which
permitted iron oxide crystals to break down into their soluble ferrous
form into the soil solution thereby triggering not only ethylene gas but
liberating essential plant nutrients otherwise bound to iron oxide, clay
and organic matter particles.
The big thing is that soluble nitrates (exceding trace element levels)
prevents the iron from breaking down which in turn prevents the release
of both ethylene and bound nutrients.
What this research effectively proved was that the use of soluble nitrate
fertilisers, excessive use of natural ammonia fertilisers (manures &
leguminous green manures) prevents this process as does ploughing/tilling
the soil and burning. An Ag chemical company wouldn't want to hear this
stuff, especially in the 1970's when organics was still regarded as
fairyland stuff and totally unscientific.
>I am also aware that scientists carry grievances for slights such as being
>turned down for research funding and so on and that this can influence what
>they say to people. The question becomes how to discern what is likely true.
Interestingly I saw an article in New Scientist early 1989 about a
British soil scientist working in Africa. He came up with the same stuff
about anaerobic microsites, iron and nutrient release and the inhibiting
function of nitrates but not the ethylene connection. The fact that an
indepenent study on another continent came up with the same thing (except
for ethylene) to me validates this research.
By the way when I tracked down Smith in 1985 to invite him to the PC
convergence at Otford he was then the director of the Rydalmere Chemical
and Biological Research Institute. He actually posted me the Departments
Annual Reports that contained references to his work before it was
terminated & still have them in my library. While he said his 'lips were
sealed' on that particular research he was keen for us to get the word
out and grateful the PIJ had published his only conference presentation.
>As for the cycle, I have found that students find it a very difficult
>concept to comprehend. I have watched a number of experienced permaculture
>teachers attempt to describe the permutations of the cycle.
Since my first PDC I've found ways to teach this cycle in a comprehesible
way & when there's enough students we act it out - that's a ton of fun
and really consolidates understanding of the process. I think that
understanding this process is essential to fully appreciating the
intricacies of soil and has major implications for how we manage it.
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