Monday, 23 August 2010

Peak phosphorus.

Phosphorus is an element....  like carbon or oxygen or iron.   It's one of the elements that is essential to plant growth and so it is added to fertiliser as a phosphate compound, especially in Australia where the soils are old and the soluble compounds dissolved and leached out by millions of years of rain.
Plants need phosphate to produce phospholipids which are a part of the cell membranes of every cell.  Without it, plants just can't grow.

People have known that phosphate is needed for plant growth, even before they understood the chemistry.  It is found in broken down plant material (compost), manure and guano, and as rock phosphate that can be mined.  Compost and manure are good,  but the concentrated phosphate found in guano (that has been mined from islands where bird rookeries have been for centuries) and the rock phosphate that has been mined from deep in the earth are both reaching "peaks." This opportunity to use mined phosphate as "super phosphate" formed a part of the green revolution.

In the same way that we are used to seeing the "peak oil" graph with its common "bell curve" shape in recent years, there is also a "peak phosphate" graph....

... this shows peak phosphate occurring at about 2035.... 25 years from now.  

And below the graph shows the increase in the amount of phosphate used, with the huge increase coming with the green revolution.

I have been reading in the newspaper recently about the BHP attempt to buy the Saskatchewan Phosphate Company.  Their first offer was turned down.  It is obvious that in about 25 years from now, when phosphate production begins to reduce,  prices should skyrocket.  The long term strategy for any mining company then should be to acquire access before the shortage is apparent and while prices are still low.  These negotiations are apparently tough.  There is a lot of profit to be made in a few years time.  This negotiation among the big mining companies is the surest indication that peak phosphate is being considered by them as an opportunity.

The phosphate that is incorporated into food plants and eaten is normally lost in waste water, and often pumped out to sea, becoming unavailable for the forseeable future...  at least until the conditions on the earth change significantly enough for this phosphate to end up in sediment and then rock phosphate again...  conceivable millions of years.  Phosphate can no longer be wasted in this way.

My garden needs phosphate too.

When I first moved to this house,  there was an aviary in the yard (now converted to a fox-proof chicken run.)  The previous owner had had pigeons, and there was a huge deposit of guano inside the fence.  I dug it into the garden and my vegetables grew magnificently.  The chickens continue to produce manure and this is all returned to the soil.  And then there is compost, some occasional additions from various manures when they are available.  
In the long term, though, everything that grows on the soil here is using minerals from the soil,  including phosphate and for the long term, it is necessary to recycle all of these nutrients.  This is a part of the reason that I don't "export" plant materials from my little acre.  Weeds are either composted,  turned into "stinging nettle fertiliser" or fed to the chickens.  

My "green waste" bin remains unused.  

As peak phosphate arrives, the security of our food supply will be threatened and yet food security doesn't seem to be a priority yet.  

I am able to grow enough food to feed this family, and while our diet might be a bit more limited without  outside possibilities,  we would certainly eat quite well if dependent upon this garden.  

This didn't happen overnight though.  In various blogs and articles I have read about people who seem to think that "when the food supply is threatened"  they will plant a garden and grow some food.  

It has taken me about five years to be able to produce food reliably.  It takes practice and, like other things, it's a learning curve.  It's not all hard work and worry though...  it is good fun too!
It is a whole new way of living.

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