[Arid_gardener] Question from Home-Hort WWW page

[Dick Gross]

Marnelle, I don't know what a certified, bonified soil scientist would do 
but, if I had that problem in my yard, this is approximately how I would 
deal with it.

In the area where your plot lies, dig two holes about 8 to ten inches wide, 
3 or 4 feet apart and 15 to 18 inches deep. If down a foot and you find a 
jack-hammer is needed to go deeper, you have already found the problem. An 
impervious layer that could just be compacted soil won't let the water 
through. Roots can't breathe and evaporation from the surface will 
concentrate salts to toxic levels and plants will just languish or die.

Our water has a high salt load that must be continually flushed through the 
zone. You can never get the soil level lower than the water concentration, 
about 8.5 wt. percent where most of our plants will survive if salt is not 
allowed to accummulate by evaporation to a higher level.

Fill the holes with water and determine how long it takes for the water to 
drain into a lower level. If it happens quickly fill them again and again. 
When you reach a point (you may never) that the water stands in the hole for 
a long time, you have exceded its drainage capacity. Roots in that 
environment will likely rot before the water table moves out. You must 
irrigate in a manner or at a rate that never reaches that level. If 
saturation has forced out all of the air, roots won't survive very long 
without it. Once you are familiar with your drainage capacity, you needn't 
test with holes again,

Uncomposted organic debris will continue to decompose in the soil through 
the activity of micro-organisms but the process uses available nitrogen 
desparately needed by the plants. In those conditions, I add 21-0-0, 
Ammonium sulfate, to feed the plants and make up that consumed by feeding 
soil organisms. I can't tell you how much--I don't know, but, I dust the 
beds perodically with 21-0-0, one or two weeks apart, and water it in well. 
I have never burned anything but excess can do that.

If your soil compacts readily, or is compacted, it might help to add gypsum 
and compost to loosed it up. Ask your nurseryman how to apply and blend it 
in.

I have two compost bins that I try to turn over weekly to aerate it and add 
21-0-0 as I do. I use a shredder to break up leaves and small branches into 
the smallest possible particles with the maximum area from which soil 
organisms can feed. Organic material is not compost until or unless it has 
been eaten by soil organisms and processed through their guts tearing 
complex organic compounds apart and reducing them to elements that plant 
cells can use as nutrients. Heat in a compost pile is generated by the 
digestive process but can't happen without moisture and occurs much faster 
if nitrogen is abundant. You can add nitrogen from the bag or blend green 
organic material like newly mowed grass,

Another procedure I've used is this. In a contained bed, add about four 
inches of  shredded leaves and other organic debris to the top and keep it 
damp. Sprinkle a little 21-0-0 over it ocassionally. Organisms will feed off 
the bottom gradually comsuming it. You will have to gradually add more 
material but if you can wait until a much later date to plant tomatoes, I 
find it a good way to breed new life into dead soil.

Marnelle, I don't know if this hodge-podge will answer all your questions 
but should reveal part of the problem. Other Master Gardeners should jump in 
to contradict this analysis or add solutions of their own. Learning won't 
occur until such a dialogue has taken place and most gardeners confess that 
their ignorance is paramount and intelligence is what follows learning by 
trial and error.

Our desert soil has most or all of the elements needed to support plant life 
except organic material that must be added.

In 1933, on the Nebraska farm where I grew up, my dad disc-under a four foot 
stand of clover in a 20 acre field in the fall. In the spring, he planted it 
with red potatoes. The yield averaged 500 bushel to the acre. A typical 
yield seldom exceded 250 bushel. Organic material with a high nitrogen 
content doubled the production drawing farmers from all over the State to 
see it. Even I, aged nine, was awed.

That is evidence of the critical role of organic material in soil.

Dick Gross, Master Gardener Volunteer
University of Arizona Maricopa County
Cooperative Extension

Bcc: vosg, azcrfg


----- Original Message ----- 
From: <marnelle.north at cox.net>
To: <arid_gardener at Ag.arizona.edu>
Sent: Thursday, May 17, 2007 9:36 AM
Subject: [Arid_gardener] Question from Home-Hort WWW page


> Marnelle North
> 85044
> marnelle.north at cox.net
>
> I have gardened (mostly veggies) for several years. I do a lot of soil 
> prep before planting, Spring and Fall, (watering, breaking up soil, 
> additives, mulch, etc.) Even when I am watering consistently, every year I 
> run into the same problem - compacted soil and water run-off. I'll slow 
> water with sprinklers on low and close to the ground for lengthy periods 
> (until I see the water running out of the beds.) The plants stay alive, 
> but don't flourish and when I dig down and inch or so, I encounter dry, 
> dusty soil. It is insanely frustrating, especially when I tend to the 
> plots every morning, not to mention a waste of water. How do I help the 
> soil retain water instead of shedding it? Thanks for you help.  - Marnelle
>
>
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