814-Lancaster Farming, Saturday, March 16, 1991
Satellite Conference Studies Ways To Prevent Soil Compaction
ANDY ANDREWS
Lancaster Farming Staff
HERS HEY (Dauphin
Co.) What do silage trucks,
gram bins, manure spreaders, and
combines have in common?
For- one thing, they arc major
contributors to soil compaction on
the field.
And soil compaction contri
butes to plant disease, yield prob
lems, and other factors detrimental
to farming.
“The most common cause of
compaction problems is getting on
the field at the wrong time of the
year, (using) tillage tools, discs or
plows, or getting on the field with
heavy loads,” said Lynn Hoffman,
agronomy senior research associ
ate at Penn State.
Broadcast downlinked
Hoffman spoke to farmers at a
Crop Production Satellite Seminar
broadcast from Mitchell Studio B
at University Park. The broadcast
was “downlinked” to various
locations throughout the state,
including Hershey, Hazleton, Wil
liamsport, and other sites.
At University Park, signals were sent to G
Star 1 satellite on the Ku Band, Channel 12, at
11,927 megahertz. At the Hershey downlink
location, about 30 farmers listened to Penn
State crop experts on studies dealing with soil
fertility, compaction, plant diseases, and pest
problems.
Hoffman spoke about soil compaction and
the effects on crop growth.
In general, the higher clay content of the
soil, the more likely a farmer will encounter
compaction.
Test for compaction
But farmers must first be able to test for
compaction and determine if, in fact, other
problems exist in the field as well.
The best way is to lest for compaction.
Sometimes the compaction layer could be on
the surface or up to 8 inches below the sur
face, according to Hoffman.
To identify a compaction problem, a farmer
can dig with a backhoe or use a shovel to find
the compaction zone. Or if they take a soil
sample, the common soil probe, if used to
push the soil, can determine where compac
tion exists.
“If you have a compaction problem,
there’ll be a spot there where you’ll feel some
resistance and all at once that soil probe will
go down much easier,” said Hoffman. “If
this shows up m your field more than once or
twice, try to watch and see if it’s showing up
at about a consistent level.” Hoffman said the
compaction could be deeper than the topsoil.
Reach beneath topsoil
Another way to measure compaction is
with a Vi -inch rod with a handle welded to the
top. The probe is long enough to reach deep
beneath the topsoil. Or farmers can use a pen
etrometer a device like the soil probe
which includes a resistance dial to determine
a range of compaction layers.
“It’s important that you recognize just
where that compaction layer is in the soil,” he
said. There are a few ways a farmer can
relieve compaction. One is by planting some
crops that have the ability to penetrate the
compaction layers (such as soybeans, buck
wheat, or alfalfa) which have a good rooting
system, said Hoffman.
For a shallow compaction problem, stan
dard tillage equipment can break the zone. For
a deeper compaction problem, farmers can
use deep tillage equipment, such as a V-ripper
or a paraplow to get the job done.
It’s important, according to Hoffman, that
farmers find out exactly how deep the prob
lem is. “You don’t want to relieve that com
paction with your deep tillage tool any deeper
than that compaction layer. If you come back
m there with a piece 9f heavy equipment and
rccompact the soil, it’s going to compact
down there at the depth you actually relieved
the compaction layer the last time.”
Panelists answer questions from the satellite audience at
the conference. Left to right: Marvin Hall, assistant profes
sor of forage management; Greg Roth, assistant professor
orf corn management; and Lynn Hoffman, agronomy senior
research associate.
Modify equipment
Preventing compaction is
another way farmers can curb the
problem through the use of equip
ment modifications.
In the case of a manure spreader,
a farmer can use 1020 truck tires
with tandem axles. This spreads
out the compaction zone. Also, flo
tation tires (using 22-28 pounds of
pressure per tire) can create a diffe
rent footprint to help distribute the
weight of the load that is placed on
the spreader.
“The amount of compaction
you cause on a load will be in
direct proportion to the amount of
air pressure you have in that tire,”
said Hoffman.
Using a different type of tire or
HOWTO A/ODGETTIIG BUCK...
seni
Penn State, spoke to farmers at a Crop Production Satellite
Seminar broadcast from Mitchell Studio B at University
Park. The broadcast was “downlinked” to various locations
throughout the state, Including Hershey, Hazleton, Wil
liamsport, and other sites.
tire width is an important consider
ation, “one that you can carry out
to other tools on your farm like sil
age wagons and grain wagons,” he
said.
Tandem tires
Front tractor wheels also hold to
about 30 to 50 percent of the total
load. But using tandem tires or
wider tires can also help consider
ably in reducing compaction. Also,
a four-wheel drive tractor reduces
compaction because it reduces tire
slippage. (Turn lo page B 15)