permaculture

[Paul Cereghino <paul.cereghino@comcast.net>]

I am enjoying this strand, and it has made me want to brush up on 
chemical interactions in the soil solution!

Here is another scenerio studied by one of my cohort in school:
Phosphorus fertilization is promoted by the horticulture industry 
particular for flowering plants.  Our damaged soils are typically low in 
calcium with low CEC.  Excess soluble phosphorus immobilizes by bonding 
with available iron, resulting in iron deficiencies in some succeptible 
species.

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

(and a side note.. a local organic guru Steve Solomon made a precise 
critique of Fukuoka's continuous grain harvest system by noticing that 
he is farming on phosphorus rich soils.)

Thanks Lawrence for the tip on local quarries... duh!... I will check 
out my local rock crusher, their source of stone, and if they spray 
floculants (which i know little about) for dust control.

I feel compelled to make a plug for working carefully with your existing 
mineral base.  Although we can manipulate the pools of various elements 
in the soil, I'd be willing to bet that the continuous availability of 
those elements is dependant on biological activity that increases the 
cycling of elements, and thier incorporation into soil food webs.  And 
that 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 know all you folks are thinking about these things... but I know that 
our culture has a proclivity toward reducing complex things into 
consumer solutions... and so I take the soap box (no phosphate pun 
intended) only out of compulsion -- no patronization intended.  The 
'health and sustainability' market is just beginning to mature, and the 
snake-oil salesmen have always loved gardeners.

Anyone have any good resources on 'dynamic accumulators' of phosphorus 
or other elements?

>