Here is an Article from the AG department: It might help..
http://ag.arizona.edu/gardening/news/azdailystar/dealing_soil_problems.html
Dealing with Caliche and Other Desert Soil Problems
A recent caller was in hopes that pouring pool acid into a bed on caliche
would somehow loosen it up. Applying acid makes sense, as caliche is a layer
of lime (calcium carbonate) which forms in our desert soils. The problem is,
it doesn't work.
You would probably have to pour a tanker truck full of sulfuric acid in a
hole with caliche to make much of a difference. Mostly what you would get is
a lot of alka seltzer-type fizzing.
Dealing with caliche isn't easy. Digging it out can be an arduous task.
People use everything from picks to jack hammers with mixed results. If the
caliche is fractured or cracked, which is often the case, it is easier to
remove. If it is solid, it can be as hard, and impervious as concrete.
The first thing you must decide is: do I really need to plant in this spot?
Sometimes just moving the planting hole a few feet over may provide space
for digging. If it's a garden you want, think about constructing a raised
bed. Good soil can then be added to your frame to grow whatever you want.
This is a great way to grow flowers, vegetables, and herbs.
If your planting trees or shrubs, consider mounding up your plants so they
can grow above the caliche. This works if you have at least 8 or 10 inches
of top soil overlying the caliche layer.
Dig a hole down to the caliche. Next, test the drainage by filling the hole
with water several times during the day. Drainage is poor if water is still
standing 24 hours after the last filling. It may be necessary to place a
drainage chimney through the caliche. This chimney hole should be dug to the
side, not directly under where the plant will sit. The drainage hole should
be about 6 inches in diameter, and filled with soil (not gravel).
For shallow hole planting above caliche use plants in small containers. For
instance, buy a tree in a small 5 gallon pot. This way a good part of the
root ball can be set into a shallow hole. Mounding up soil up around the
exposed portion of the root ball will allow roots to grow out and into the
surrounding soil. This mounded soil should be gradually tapered away from
the plant so that it eventually blends into the surrounding soil.
Even if caliche is not present, it is often hard to dig in our desert soils.
This is due to a high clay content and also gravel. Wetting the soil before
digging makes the work easier. If you're putting in a lawn, vegetable garden
or flower bed, tilling in lots of organic matter will really improve the
soil. The organic matter can be desert compost, peat, or composted horse or
cow manure. A three or four inch layer mixed into the top foot of soil will
make future digging and planting easier. Plant roots will also have an
easier time growing in this improved soil.
Do not amend the soil when planting trees and shrubs. Research has shown
that adding organic matter to the planting holes of trees and shrubs is
detrimental to their growth. Simply fill in around the roots with the same
desert soil which you dug out of the hole.
Our desert soils are rich in most nutrients. However they are often lacking
in nitrogen and phosphorous. These are the first two of the three number
analysis listed prominently on the fertilizer bag. Nitrogen can be surface
applied and will move down into the soil. Phosphorous moves very little in
the soil and therefore is most effective when mixed into the soil at the
time of planting.
Iron deficiencies also develop on some acid loving plants such as gardenia,
rose, citrus, bottlebrush, and nandina. Although there is sufficient iron in
the soil, it is not available to these plants because our soils are
alkaline. Typical iron deficiency symptoms appear as chlorosis of the new
foliage in which leaves are yellow with the veins appearing as fine green
lines. Eventually entire leaves can turn yellow. Iron deficiencies can be
corrected by the addition of chelated iron to the soil. Chelated iron is a
water soluble form of iron available to the plant even in alkaline soils.
On 9/12/07, Richard Daines <
rjdaines@gmail.com> wrote:
>
> Not a geocaching question since we are not allow to dig or use pointy
> objects to make holes but I can't see that that is a problem for Arizonans
> in the desert areas since I find it virtually impossible to dig a hole in
> this caliche soil. I believe it's also known as hardpan. Just how to you
> guys dig a hole, my gosh, I just wanted to plant a few cacti before the
> temps went over 100F one morning.
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