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Greening a Desert where it rains.  RSS feed

 
Denise Lehtinen
Posts: 102
Location: Tampa, Florida zone 9A
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I have heard Florida described that way... as a desert where for two months in the summer we have daily thunderstorms that'll soak you worse than standing in a shower when you dart from car to house.

The permaculture techniques that I have heard of (okay that isn't really that many actually) seem to focus on issues that clay soils have. But here in Florida I am dealing with a "soil" that is nearly 100% sand.

Are there some techniques you can direct me to that will help me bring lasting fertility to soil that likes to hold neither water nor nutrients nor organic matter? (It is sand and everything seems to wash through it.)
 
Jonathan 'yukkuri' Kame
Posts: 488
Location: Foothills north of L.A., zone 9ish mediterranean
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In many sandy tropical areas nutrition is stored mostly in the canopy, don't worry too much about soil amendments for the food forest. A layer of mulch on the surface is probably sufficient.

Containers work well to contain rich soil on a small scale.

I figure not much will wash through poly-lined aquaculture ponds.
 
Hanley Kale-Grinder
Posts: 112
Location: Mountain West of USA, Salt Lake City
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I lived in the sand by the ocean once. First I dug a pit shaped like a box. I then put a board on the bottom of the pit and back filled it with aged horse manure and topped with top soil. It worked great until the gophers found it. I'd imagine it would work even better if you used side boards. The concept is basically a raised bed that is dropped into the ground..screws etc. are not necessary.
 
nancy sutton
gardener
Posts: 645
Location: Federal Way, WA - Western Washington (Zone 8 - temperate maritime)
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I wonder if incorporating biochar (terra preta) along with the manure/organic/etc. material would lead to increase in water- and nutrient-holding capacity... ? (See YouTube video 'The Secret of El Dorado".)

Also, bentonite clay (available from drilling suppliers - it is used to seal the holes). Here's a quote from "Basics of Permaculture Design" by Mars (aimed at Australian audience), that I just happened to be reading today... "Bentonite clay - expansive clay to increase water holding capacity of soil and cation exchange capacity of light sandy soils."

Eliot Coleman has good things to say about its benefits for his "sandy soil" in his "The New Organic Gardener" pg 116-117 - re: the montmorillonit/bentonite type of clay, including reports from a Michigan State study showing "impressive improvements in yield, moisture retention, and nutrient availability on sandy soils..... Montmorillonite has highest CEC of all mineral soil compondents....plus it is a permanent addition to the soil that will affect a long-term improvement, rather than short term stimulus."



 
Geoff Lawton
permaculture expert
Posts: 48
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Hi Denise
you can use bentonite powdered clay in a garden area and get a quick result by mixing it with your soil then, a thick sheet mulch of paper or cardboard and then compost or manures then a thick layer of mulch. On larger areas use swales to grow a dense diversity of hardy nitrogen fixing pioneer trees that like to grow in sandy soils and chop and drop mulch the swales with their abundant surplus growth of branches and foliage to stick your sandy soil up with water retaining organic matter creating a higher humus content.
 
Denise Lehtinen
Posts: 102
Location: Tampa, Florida zone 9A
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I'm thinking that yukkuri kame's suggestion is most workable. Soil doesn't hold nutrients here. The canopy does...living plants do...large slow decaying things do.

Hanley's idea sounds like the method I've seen used in an organic farm around here. It'll grow a garden for you all right, but you've got to remake the raised beds from scratch every year, too.

Bentonite clay, if my information is correct, is a key ingredient in kitty litter -- especially the clumping type. When my kitty died last year I put the remainder of her litter out on the grass to see what would happen. I see little or no sign of any of it in that area any more. It has almost all washed through. The plants I hoped to encourage, didn't have any growth spurt either. That was the regular clay kitty litter, so not a fair test of Bentonite clay really. That is a possibility to try someday. (I won't believe it until I see it that it will stay any place that I put it for very long.)

I have also been trying the terra preta idea. I have been wondering if maybe the right approach is to skip the turn it into a powder stage, and just add the charcoal to areas still in twig form -- and thus reduce the washing it away effect.

I also have a hugelkultur pit experiment going. I expect that it will be a major termite attractor (termites love decaying wet wood out of the sunlight), and that the wood will be gone from there in less than a year, but I am holding out hope that I will be proven wrong about that.

Another approach to hugelkultur I am trying (and which I have more hope for), is just adding the branches on top of the soil. Do this a little at a time, like what happens in a forest during a wind storm. These branches decay slowly, and therefore release their nutrients slowly. They increase the availability of moisture to plants growing near them. In that area I already have a perennial legume growing, so I think I have a nitrogen source there...

You know, I just had a light bulb go on, the other item that contributes slow release fertility around here is sweet potato. Some of them grow as perennials in Florida. I think that would be an apt addition and be a source of a whole different set of nutrients for plants in that area.

Thanks everyone for your help, (and I won't object to more, if you want to give it).
 
Adam Gulliford
Posts: 20
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Denise Lehtinen wrote:

I also have a hugelkultur pit experiment going. I expect that it will be a major termite attractor (termites love decaying wet wood out of the sunlight), and that the wood will be gone from there in less than a year, but I am holding out hope that I will be proven wrong about that.



We've all heard of the benefits of worm castings and such. Is there a nutrient rich bi-product that comes from termites? Or what are some of the uses for termites in a permaculture system in general? I assume they make great pathways and air pockets for plant roots and water. What should we do if they start getting too close to our wood structures (house,barn,sheds).
 
Brenda Groth
pollinator
Posts: 4434
Location: North Central Michigan
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I'm also not desert, however, there have been serious droughts in our area from June thru August for the last 4 years or so, so I am kinda dealing with a similar situation. I however have both clay and sandy soils. I have done as Geoff mentioned above in areas where there isn't a good water retention .. esp by some of my fruit trees. I had one fruit tree that was just doing terribly although the soil was very fertile..and then I realized the slope it was on was so steep that water was running right past the tree, mulch and all. SO, I did dig a small swale by the downward side of the tree area, I placed a few bricks in the far edge of the swale (had em laying around) and I filled the ditch with mulches..the tree perked up in no time..so this might also work for your wet desert??
 
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