Cob RE: sustainability and straw (long)

[John Schinnerer]

Aloha,

-----Original Message-----
From:	S. William Edwards [SMTP:cr975 at freenet.carleton.ca]
>I thought I had read that if all the straw left in the fields in
>the US was used in straw bale construction there would be enough material to
>build 5 million homes.

Perhaps - but this is a one-shot deal, a "quick fix,"  an extrapolation of existing numbers that does not include larger contexts (such as time...).  Five million homes is a drop in the bucket nationally, let alone globally, but it might be enough so that it would really catch on.  

Then what?  Where did the straw come from?  How did it get there?  It grows, and in growing it uses resources - sun, air, and elements from the soil.  Plants get most of what they need from sun and air, but a small portion comes from the soil - critical minerals, nutrients, etc..  Some of this ends up in the grain we eat and therefore does not return to the growing soil for hundreds or thousands of years.  Some of this ends up in the straw, which we do not eat.  If the straw is composted and the compost used to re-enrich the soil the straw was grown in, the nutrients and minerals that went from the soil into the straw go back into the soil and the cycle can be continued - the next crop can use the returned nutrients to grow.  

If the straw is taken away from the field and put into a house, whether in cob, straw bale, or pressed straw board, the nutrients are locked in that house and do not return to the soil (until the house decays, anyhow).  The next crop then draws more nutrients from the soil, and in a relatively short time there are none left and no straw (nor grain, nor anything else) will grow.  At present, nutrients are imported from outside, as either manufactured chemical or organic fertilizer, to replace the ones lost when the straw is burned or otherwise removed.  The question then is "where did those nutrients come from?"  From somewhere else where they are now not available to plants that might grow there...plus the energy used to process and transport them...

	>I also understand that in California they burn "waste" straw which
>causes obvious environmental problems.  According to a program I was
>watching there was a lot of interest in making paper using straw which
>would help limit the amount that would be burned.

I agree it is clearly better to build dwellings with straw, or make paper from it, than to burn it.  However, these "solutions" still consider *all* the straw as "waste."  They neglect to account for the fact that taking all the organic matter away from where it grew also takes all the accumulated nutrients and minerals away.  If these practices do not change, in time there will be no soil to grow straw (or anything else) in at all and it won't matter if it was burned, made into paper, parts of houses or whatever.

Ecology Action, working on researching small-scale fully self-sustained Biointensive farming methods for the past 20+ years, has estimated that a Biointensive farmer could "afford" to export (that is, sell to others) at most roughly 10%-20% of his food crops.  Removing more than that would result in the need to import nutrients.  So if 10% of the straw went towards housing construction and the rest was returned via composting to the soil, that *might* be sustainable - only time would tell.  Taking it all seems clearly unsustainable.

The Lundberg family, who are organic rice farmers in the California central valley (Lundberg family farms brand), do this with a portion of their fields:  after they harvest the rice, they flood the fields with a about six inches of water (also problematic water-use-wise, but I won't go into that...) and leave the straw standing.  A combination of natural decomposition due to the water, and the fertilizer and "trampling down" contributions of migrating waterfowl who stop in the flooded fields to eat leftover grains after the harvest, enable them to grow a new crop the next year with minimal input of imported organic fertilizer.  If they burnt or otherwise removed all the straw, they would need to import more fertilizer, thus being less sustainable.  They seem to be doing about the best they can for a large-scale farming business, and it's a great example to start with.

>It seems unlikely that there would be any nation wide shortage of
>straw even if it became a popular building material.  

Not right away, of course.  It might kick in when crop failures from unsustainable farming practices did, or perhaps sooner if the whole housing industry switched over within a decade...I'm curious why it seems unlikely to you.  Wood is a (very) popular building material, and in half a century or so we've gone from incredible abundance and quality to scarcity and poor quality while having destroyed all but a tiny fraction of old growth forests and lost most of the soils necessary to replace trees cut.

I'm inviting people to think beyond their immediate desire for a so-called eco-friendly politically-correct house to the larger systems involved and the larger changes that will need to take place for us to survive as a species.  To me, it's sort of like the fascination with electric cars - if every car in L.A. (or Seattle :-) were replaced with one tomorrow, the smog might clear after a while but the gridlock would still be the same and all the heavy industry pollution from manufacturing the cars would be the same and who knows what else that no one stopped to consider might turn up as additional consequences on the negative side of it all.

>And I am not sure
>what "all the consequences" would be.
 
That's the invitation - to consider the question.  I do not know either, but I feel it is critical to keep asking the questions rather than rushing blindly towards whatever the currently popular cliff is.  It's not really what houses are made of that is so unsustainable - it is the manner with which (how) they are made, as production-line elements within an economy that believes in endless growth and uses resources unsustainably.  Any resource can be used unsustainably - trees, bamboo, straw, soil, water, air, whatever.

I'm not suggesting throwing in the towel and building a sheetrock box.  We can encourage ourselves to do the best we can with what we have now, but I do not feel that is enough.  There are always more hidden assumptions to uncover that might take us to the next level of understanding our part in the big show.  It's a hell of a lot of fun to seek them and find them, too!  For me, anyhow... :-)

Cob still looks pretty good as a specific building method, because it uses far less straw (and energy...how did that straw get into those bales, after all?  Not to mention manufactured panels...) per building than straw-bale, Agriboard-type stuff, light-clay, etc.  But what other consequences are we still missing?  I say keep digging...and build that cob cottage too...but don't take anyone's answers (especially mine :-) to be your own.

John Schinnerer