permaculture

[Ute Bohnsack <sustag@eircom.net>]

Mark wrote:
> 
> At 01:39 PM 9/20/02 -0500, you wrote:
> >I have just bought 23 acres of  sandy land ( almost a beach) with close to
> >no organic matter in  a tropical drylands area...
> >Although I plan to use the strategy of intense dryland polycultures to
> >create on-the -spot organic matter,
> 
> All good replys so far.  I'd add that you might want to look at imprinting
> the soil to create little dips that concentrate water and OM.  This can be
> very helpful in such sandy ground in establishing vegetation.  You may be
> able to archive this with the cattle's foot traffic.  You will also find
> that adding even small amounts of clay to sandy soils can be very
> beneficial, try mixing it into compost piles.  Good luck and keep us posted.
> 
> Mark P. Ludwig

Mark mentions clay - rock dust is also good for the same purpose as it
helps in humus building and water holding capacity, if you can get it
where you are, that is.
To tie in with Mark's suggestion about imprinting: one technique you
might look into is "trench gardening" or "deep trench gardening", as
rediscovered and promoted by Robert Mazibuko in Natal, South Africa.
There they get most of the precipitation (815mm according to my German
language book source) in the summer while the frost-free winter is a
drought period. 
If you type "Mazibuko" "trench" and "garden" into www.google.com you
will get a few hits amongst which
http://www.farmradio.org/english/60-9script.html is the most
descriptive. An infosheet on the technique is available from
http://sol.crest.org/sustainable/ecology_action/infosheet.html (not for
download unfortunately).
Another description for scouts -yes, scouts! - is at
http://www.scouting.org.za/bp4life/kit3-1.html#proj1 (lovely site BTW) 

The description I have says that a trench is dug 2m wide and 90cm deep
with the top, middle, and bottom soil layer kept separate. Then the
trench is filled with
5 cm from top soil layer
30 cm 'steppe grass' ("elephant grass" a course grass that even cattle
don't eat)
5 cm from middle soil layer
30 cm 'steppe grass' 
5 cm from middle soil layer
30 cm 'steppe grass' 
5 cm from bottom soil layer
30 cm 'steppe grass' 
35 cm top soil and remaining middle soil layer
The trench is then sown with a fast-growing legume (unnamed in the book)
which is incorporated as green manure at the onset of flowering. Root
crops are grown first, then leafy veg and from thereon follows mixed
cropping.
Apparently this method allows the retention of so much water that no
irrigation is needed for cropping during the dry season, and the
trenches, once established, can be used for years. 

I take it other organic materials can be subsituted for 'elephant
grass'. It's quite elaborate but seems a good dryland technique and may
be worth a small trial.

Now if I did that here, I'd have a pond...

Good luck with your work Marsha.

Ute (in Ireland)