Ethylene-oxygen cycle

permed at nor.com.au permed at nor.com.au
Thu Dec 13 21:10:05 EST 2001


Russ wrote:
>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
>those interested.
>What I found was that there had been no research since the cycle first
>attracted attention.

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.
Robyn




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