permaculture

[Dieter Brand <diebrand@yahoo.com>]

Thanks Lawrence,

The shading from plants may reduce evaporation but that is probably more than 
offset by transpiration via the leaves.

I hit on the idea of trying to encourage algae growth in my irrigation system 
because of something I read about high fertility in some of the ancient 
cultures in which irrigation was used.  It was assumed that part of the 
fertility was due to the algae that would form in the extended network of 
irrigation channels.

Dieter


--- On Sat, 11/19/11, Lawrence F. London, Jr. <venaurafarm@bellsouth.net> 
wrote:

> From: Lawrence F. London, Jr. <venaurafarm@bellsouth.net>
> Subject: Re: [permaculture] Growing algae in irrigation water?
> To: "permaculture" <permaculture@lists.ibiblio.org>
> Date: Saturday, November 19, 2011, 1:06 PM
> On 11/19/2011 5:14 AM, Dieter Brand
> wrote:
> > Hi, I have a request which may be a little strange and
> perhaps there
> > is no real answer to it.  Anyways, it does occupy
> my mind:
> >
> > I live in a semi-arid region with a prolonged and
> severe dry season.
> > So, every drop of water I can save counts.  I
> have a spring up in the
> > mountain and several water holes which together
> provide just enough
> > water to irrigate about half an acre during the dry
> season, if I use
> > it very sparingly.
> >
> > I recently hit on the idea of letting the irrigation
> water run
> > through open channels or a series of containers where,
> under the
> > light of day, algae would form in the water.  I
> do believe that these
> > algae would have a beneficial effect on the irrigated
> soil.
> >
> > The problem is that I don’t want to expose the water
> directly to the
> > sun since I don’t want to risk that any of it
> evaporates.  What would
> > be the best way to construct such waterways? 
> Should I cover them
> > with some sort of semi-transparent shading cloth that
> is permeable to
> > air?  Or should I use transparent glass or
> plastic that isn’t
> > permeable to air?  I don’t want the water to
> heat up under the glass
> > or plastic.  But if I use a shading cloth, I’m
> not sure that none of
> > it will evaporate.  As I said, I can’t afford
> to loose a single
> > drop.
> 
> Shade it to keep it from heating up and put plastic over it
> to prevent 
> evaporation
> 
> alternate: run the water into a small pool or pools,
> containers, ponds 
> where you have many aquatic plants growing including
> duckweed which will 
> completely cover the water surface, shading it and
> preventing much 
> evaporation - you will get nutrients from the decaying
> plant material - 
> you might get algae growing too but it will need nutrients
> to survive 
> and the duckweed will also feed on those nutrients and
> outcompete the 
> algae to dominate the water surface - introduce fish,
> snails and other 
> organisms that thrive and coexist with other inhabitants of
> a freshwater 
> environment. As for quality of plant nutrients in the
> output of the 
> impoundment this may be better than water from algae
> culture.
> 
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