permaculture

[Marsha Hanzi <hanzibra@svn.com.br>]

We are working with a model in the Brazilian semi-arid which has proven
successful in the first field trials for annual/permanent crops in
erratic-rainfall situations:

1) Plant Opuntia ficus indicus  one to a meter.
2) Together with every second row of this edible ( and forrage) cactus
plant local leguminous/forrage trees for  organic material.
3) Plant corn and pigeon-pea together between the cacti.
4) Plant castor-bean ( a commercial crop here but also excellent for
organic mass) every two meters. 
5) Fill the ensuing space with cowpea (Vigna), which is resistent to
drought.
6)  Plant a line of native fruit and wood trees every 10 meters. Besides
guaranteeing one more product from the system, their deep roots help
bring minerals up from lower soil levels and recycle them to the system.

Management:  Plant the cactus before the rains come.  With their arrival
, plant the rest.  Next year, prune everything which can be pruned( the
leguminous trees, pigeon-pea,castor,etc.) before the rains come
(including the cactus if it has grown a lot-- cut into small pieces
otherwise it will sprout!) and plant the annuals in the resulting mulch,
spearing it with the point  of the machete to open small holes.  All the
above crops ( one could also try millet, sorghum, and sesame) grow well
through mulch. 
        Besides conserving humidity and creating wind and evaporation
protection, this system guarantees at least forrage production ( the
cactus and the native forrage trees) in worst years, and can also
produce hay or silage.  But careful!  Anything taken away from the
system in form of forrage must be brought back in the form of manure. 
We must be careful not to "rob"the system.If the forrage trees are
pruned 30cm from the ground the first year they branch out profusely,
making live fences.  In ensuing years they can be pruned some 50 cm
above the ground.

        We are still testing and perfecting the system, and every region will
have its own version.  But we have seen that the fields remain green 
over the dry season ( pigeon pea, castor etc.) in spite of working in
regions of 300 -400 mm rainfall. We are working in tropical drylands
here
but I am sure that this model can be adapted for other dryland climates,
using the principle:
1) a cactus to guarantee sun/wind protection and forrage even in the
worst years
2) Local leguminous/fodder trees
3) Lines of larger trees for root penetration  and fruit production
4) Dense plantings
5) Mulch forming through pruning of everything at least once a year.