permaculture

[Jody Troupe <jodyt2@mac.com>]

 Paul Ereghino wrote:
          >Excess soluble phosphorus immobilizes by bonding with available 
iron, resulting in iron deficiencies in some succeptible species.

I just had a seminar last weekend and this was a topic we covered! I wish I 
had my notes handy now to restate exactly what was said - but you are correct 
about excess phosphorus in plants interfering in the chemistries of 
animals/people. I'll have to look this up when I get home.


Paul Ereghino wrote:
          >Another angle: Rock phospate (and thus all those phosphorus 
products) is a limited resource only found in a few places on earth (florida, 
morocco, ??).  

Idaho, some islands off of Spain - and Saudi Arabia is supposed to have a 
generous supply (figures).  I'm not sure where else - but its on my list of 
things to research because I was thinking exactly what you were...  is this 
another commodity? Who would own the major sources? Is it a resource that 
would become controlled? I don't want to support that either. Its just that 
right now, SRP  is completely under the radar. I can't speak for rock 
phosphate though. Is that something that might eventually be controlled? I 
have no sense of the extent of ITS use.


Paul Ereghino wrote:
          >Control of these resources is critical to industrial agriculture, 
and 
          >perhaps all eurasian inspired agriculture is some soil types.  
          >Extraction of this non-renewable resource requires political 
control, 
          >mining and energy intensive shipping.  Why would those who support 
local 
          >control, decentralization and reduction on energy dependance 
promote 
          >this economy?  I am wary of engaging in the scrabble for the last 
easily 
          >extractable phosphorus on earth.

Thank you Paul for pointing out that local sourcing would OF COURSE be 
important to permaculture. You are right. RBTI does acknowledge that 
extremely well-made compost IS a substitute for SRP. Options ARE given - 
home-grown substitutes - so you don't have to be reliant on commercial 
offerings. Perhaps, if everyone knew how to make wonderful compost, there 
wouldn't be much need for the soft rock phosphate. Though, its perhaps easier 
for someone trying to treat a larger area to give it a jump-start with soft 
rock phosphate than to try to generate a huge amount of compost. I would have 
to research if there is faster recovery for depeleted soils through this 
process than through compost,  (I'm leaning toward yes but I couldn't say 
that definitively at this point.) Fortunately, soft rock phosphate has a 
decent life-span in the soil and it wouldn't need to be applied yearly.

Maybe this isn't the forum for such an amendment that has pockets of, but not 
general, availability. But, as long as large-scale farming continues, the 
benefits of improved soil seem worth pursuing. The improved carbon levels 
would reduce leaching, working towards better aquifer quality... the balanced 
mineral make-up would reduce their need for pesticides & herbicides, the 
produce itself would be healthier, last longer... etc. These benefits would 
be passed on to all the soils' inhabitants also, improving neighboring 
soil... (like the post Ben recently submitted about 'Zai-holes' filled with 
compost that drew beneficial organisms in - what a cool bit of info!) I guess 
we're still back to the point that it isn't 'local' for everyone. Its at 
least a step in a very good direction though - healthier land, healthier food 
- there are a lot of positives, I think.


Paul Ereghino wrote:
          >...stable humus so strongly mediates cation exchange and 
phosphorus cycling that increasing the insoluble pool is less critical than 
good cycling and
          biological development in many soils.  At some point rock powder 
ammendment can be a side track if other factors are limiting plant health or 
if the system
          is producing 'well enough' such that the marginal return on rock 
powders isn't ecologically justifiable.  Rock powders obtained from far flung 
surface
          mining conglomerates, are energy intensive commodities -- and there 
are local sources of waste phosphorus.

I'm not sure if this paragraph pertains to soft rock phosphate, but SRP 
doesn't fall in the same category as other rock dusts. There is no 
'break-down' time necessary and it is immediately available to plants. The 
only reason there is a recommended 'reaction' time has to do with its 
combining with calcium in the recommended method of application. The typical 
method is to put down high-calcium lime (since MANY soils need calcium), and 
then the SRP. A minimum of a two-week window is required before planting 
young seedlings because of the tremendous energy release from the combining 
of the calcium with the SRP. A month is considered even better. SRP is not 
recommonded to be pre-mixed with the calcium before putting it down due to 
the reactions/breakdowns that would begin before it hits the soil. Its 
effects would be diluted.

Thank you for the commentary.
Jody

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