HomeMy WebLinkAboutTimes Advocate, 1991-07-10, Page 26Page 26 Times -Advocate, July 10, 1991 FARM 1 1I P 1) A rT r. •
ARCA study shedding light on pollution sources
By Adrian Harte
EXETER - After spreading manure on a field, a farmer imagines the nu-
trients and minerals will be absorbed into the soil over the next few weeks,
providing an essential boost to the crops.
However, new research by the Ausable Bayfield Conservation Authority
is indicating that something very different may be happening under those
fields.
Donna Dean and Mary Ellen Foran, water quality researchers at the
ABCA, have monitored 14 manure spreadings in the watershed area, and
have tested the bacteria count•in water flowing through the drainage tile
from those fields.
On some occasions, Dean and Foran have found bacteria -contaminated
water making its way into the drains as quickly as 20 minutes after a
spreading, or as long as seven hours. Either way, the manure was leaving
the field quicker than previously thought possible.
"Conventional hydrology doesn't allow for that," said Dean, adding that
4he rapid flow of liquid manure through "macropores" such as worm holes,
cracks and root cavities is the only plausible explanation.
"A lot of people didn't believe what we were finding. I think they were
a bit shocked, but it kept happening and we just reported what happened,"
said Dean.
"Even the researchers from Guelph didn't believe how fast it came
through," added Foran.
Dean held up a slide taken at a test site. It shows water samples sitting
under a blue sky with a dry field in the background. While previous sam-
ples had found clear water running through the field tile two hours earlier
before manure was applied, the sample jars now contained a dark brown
liquid.
The ABCA study is unique in that it is being conducted in actual field
conditions, not a controlled laboratory.
"But that's more like the conditions the farmers are spreading under,'said Foran.
The problem is that with bacteria counts ranging from the tens of thou-
sands to the millions of fecal coliforms per 100 mililitres reaching drains,
ditches and rivers, the chances for serious pollution are higher than previ-
ously !brought. When bacteria counts reach 100 fecal coliforms per 100
mililitres at the lake, the health units close the beaches - although faulty
rural septic systems and cattle being given access to streams and rivers are
also considered contributors to lakefront pollution.
If there is any good news to be found in the study, it is that Dean and
Foran have discovered conditions under which this flow of bacteria can be
slowed. When the tile drains are dry, or the field has been recently culti-
vated, then the manure products take longer to reach the watershed. When
the manure remains in the soil longer, the nutrients are beuer absorbed
and the fecal coliform bacteria eventually die off.
The discovery that cultivation slowed up the flow came as something of
an accident. One of the farmers in the study was planting a late crop of
beans and had just tilled his field before fertilizing. The assumption is that
cultivation breaks up the macropores and allows retention of the manure
spray.
Dean and Foran also added a harmless tracer bacteria to manure spread
during the tests and even found it made its way to test wells in ground wa-
ter 8-12 feet below the surface.
Local farmers who are participating in this study are watching the results
closely because they may give an indication of how future restrictions on
manure application may be formed. Ontario has few, if any restrictions on
the use of manure as a field fertilizer, whereas Quebec has already banned
Conclusive
evidence
Mary Ellen Foran (left) and
Donna Dean have slides which
show how manure fertilizer
makes its way through to
drainage tile faster than
previously believed
Viral vaccine
study for
cattle disease
REGINA - Researchers have dis-
covered that certain types of viral
caulc vaccines may limit the effec-
tiveness of other vaccines if they
arc given concurrently.
The Veterinary Infectious Dis-
ease Organization (VIDO) is study-
ing how vaccines which contain
live viruses may interfere with the
ability of bacterial vaccines topro-
tect calves against diseases such as
shipping fever pneumonia.
Most livestock producers vacci-
nate their animals against shipping
fever and other diseases upon entry
into the feedlot, often giving the
two or three injections at the same
time. VIDO has found that some
live virus vaccines appear to sup-
press the calfs immune system,
thereby limiting the effectiveness
of other vaccines to properly immu
nize the calf.
Modified live virus vaccines con-
tain viruses which have been week-
end so that they do not cause dis-
ease. These viruses contain
components which stimulate the
immune system to protect the ani -
anal. However, certain viruses may
also contain some components
which interfere with the immune
response. As a result, the vaccine
may not be as effective as possible
because the different parts coun-
teract each other, says Hodgman.
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•
the winter spreading of manure to prevent contamination of spring run-off.
The elimination of winter spreading would force many farmers into
building storage tanks to keep manure until spring.
The fact that the ABCA study has uncovered better times for spreading,
either dry periods or after cultivation, then that might aid the creation of
future regulations.
"There are conditions that are beuer than others," said Foran.
Other researchers across North America have been contacting Dean and
Foran for the results of their test§, but 'as of yet the project is still ongoing
with the pair spending long hours examining data for computer analysis.
Dean and Foran will also be presenting their findings at the Annual
Meeting of the Soil and Water Conservation Society in Kentucky in Au-
gust.
You are invited to...
A .Twilight Tour of the
Variety Plots at
ROSEBANK SEED FARMS LTD.
LORNE FELL
R.R. #2 Staffa 345-2697
(2 miles west of Staffa on Perth County Road 16)
Thursday, July 18, 1991
7:00 p.m.
Speakers: Gail Pierunek, SeCan Association, Ottawa
• What is SeCan?
Rob Templeman, O.M.A.F., Soils and Crops Specialist;
Stratford
Discussion on Barley, Oat and Soybean Varieties
Mervyn Erb, Crop Consultant, Brucefield,.
Does your Crop Production Recipe Still Make Sense?
Tours of the plots begin at 7:00 p.m.
Guests speakers and discussion on the varieties to follow
Refreshments will be'served.
Please come and bring a friend!
Brad Elder, Don Stroud, Rick Forrest
and Murray Insley
Standing in front of the
NEW 6,00O bu. per hour
Grain Elevator
To better serve the customers
in the Exeter Area. .
HENSALL
DISTRICT
(, 0 -OPERATIVE
Exeter
235-1150
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