Using an air spade to remove a layer of the compacted soil, is
considered to be more effective by its practitioners.
http://www.air-spade.com/air-spad.htm

I have regularly used a gas powered auger and drilled 3-4" diameter by
18" depth and filled with compost and inoculated with tested
biologically diverse aerobic compost tea.
http://www.intlctc.org/

Core drilling is much more destruction of the root system and may
create additional problems. Despite the risks it may be an important
part of the restoration. Great care must be taken to minimize the
damage to large roots. Compaction seems to make a tree more
suspectable to diseases. I believe that is due to compacted soils lack
of biological diversity. Compactions effect is really not unlike the
effect of "icide" usage. Simply the destruction of soil biota in both
scenarios. Simple core aeration top dressing with 3 inches of TESTED
quality compost under the entire canopy will have fairly quick
results. The addition of quality ACT and micorhizae will accelerate
the recovery.


http://soils.usda.gov/sqi/SoilBiology/soil_food_web.htm

"The Soil Biology Primer
Chapter 1: THE SOIL FOOD WEB
By Elaine R. Ingham

SOIL BIOLOGY AND THE LANDSCAPE
An incredible diversity of organisms make up the soil food web. They
range in size from the tiniest one-celled bacteria, algae, fungi, and
protozoa, to the more complex nematodes and micro-arthropods, to the
visible earthworms, insects, small vertebrates, and plants.

As these organisms eat, grow, and move through the soil, they make it
possible to have clean water, clean air, healthy plants, and moderated
water flow.

There are many ways that the soil food web is an integral part of
landscape processes. Soil organisms decompose organic compounds,
including manure, plant residue, and pesticides, preventing them from
entering water and becoming pollutants. They sequester nitrogen and
other nutrients that might otherwise enter groundwater, and they fix
nitrogen from the atmosphere, making it available to plants. Many
organisms enhance soil aggregation and porosity, thus increasing
infiltration and reducing runoff. Soil organisms prey on crop pests
and are food for above-ground animals."

Citation for this web page:
Tugel, A.J., A.M. Lewandowski, eds. (February 2001 -- last update).
Soil Biology Primer [online]. Available:
soils.usda.gov/sqi/soil_biology_primer.htm [access date].

Either of the following are correct citations for the current edition
of the booklet:
Tugel, Arlene, Ann Lewandowski, Deb Happe-vonArb, eds. 2000. Soil
Biology Primer. Rev. ed. Ankeny, Iowa: Soil and Water Conservation
Society.

Soil and Water Conservation Society (SWCS). 2000. Soil Biology Primer.
Rev. ed. Ankeny, Iowa: Soil and Water Conservation Society.

Citation for the first edition of the booklet:
Tugel, A.J., A.M. Lewandowski, eds.1999. Soil Biology Primer. NRCS
Soil Quality Institute, Ames, IA.






On Mon, 21 Jul 2003 14:27:16 GMT, wrote:

so instead of broadcasting fertilizer around the tree drill holes and fill with
compost and tea? can this help compacted soil? Ingrid