The Rural Voice, 2001-05, Page 57Research Scrap Book
Researchers measure farm pollution
University of Guelph researchers
are trying to determine if, and how,
various agricultural operations
contribute to air pollution and how
they can be altered to lessen their
environmental impact.
University of Guelph engineering
professor Grant Edwards and PhD
student Laurie Halfpenny -Mitchell
have developed a model to measure
the impact of agricultural activities on
air quality. Their work has already
highlighted opportunities for change
itp manure management practices that
would minimize the emission of
pollutants from livestock operations.
"Various agricultural operations
such as plowing fields and applying
pesticides and fertilizers, or the design
and management of livestock housing,
result in chemicals going into the air,"
said Edwards. "Smokestacks,
chemical plants and car emissions
have traditionally been targets of
concern over air pollution, but it's
now time to measure agriculture's role
in the environment."
To that end, the researchers created
a mathematical model to obtain a
measurement of each specific
activity's impact. For example, to
measure the impact of a swine
operation on air quality, factors such
as the number of swine and the size of
the barn are entered into the equation.
Likewise, when fertilizing a field,
factors such as how much fertilizer a
farmer plans to use and the size of the
field are important to consider.
Edwards says agriculture has
always contributed various air
pollutants such as dust, odour,
hydrocarbons, pesticides, ammonia,
carbon dioxide, methane and nitrous
oxide. Historically, the industry's
impact on air pollution has not been
regulated. Control was less of a
concern. But that's all changed.
"Over the years, agriculture has
evolved from small farms to large-
scale productions," said Edwards.
Farmers who apply this new model
and evaluate how their activities are
managed should be able to meet the
air-quality standard while continuing
to use the methods or applications
they prefer, he said. For example, they
could still apply manure, but a change
in the timing of how it is applied or
how it is applied would be necessary
to lessen the impact on air quality. In
the end, new management practices
will probably end up being more
environmentally friendly and
economical at the same time, Edwards
said.°
— Source: University of Guelph
Research Magazine
USDA finds simple E. coli weapon
The United States Department of Agriculture has discovered a simple weapon
in the battle against deadly E. coli, one that can be added to cattle feed with
almost instantaneous results.
USDA researchers found that adding sodium chlorate to cattle feed kills
bacteria in the rumen within six hours.
"Sodium chlorate has the potential to be a user-friendly and widely -applicable
pre -harvest intervention strategy," said researcher Robin Anderson.
Recent reports indicate 23 per cent of cattle harbour E. coli 0157:H7 in their
digestive tracts. That's the dead E. coli strain that killed people in Walkerton last
spring and the one known as hamburger disease. Adding sodium chlorate to the
diet of cattle before slaughter appears to hold promise for reducing the possibility
of cross contamination in the slaughtering process.
Sodium chlorate could be included in a feedlot ration, added to drinking
water, or given to cattle in holding yards before slaughter. Researchers gave
livestock 0.4 grams of chlorate per kilogram of body weight. The cost is about
30 cents per animal. Anderson said further testing is required to ensure sodium
chlorate does not destroy beneficial bacteria in the rumen nor change the acidity
of the gut.
The USDA researchers also checked swine and received the same positive
results for treating E. coli and salmonella organisms.°
— Source: Western Producer
Meter reads
chlorophyll levels
in leaves
In growing wheat, where
protein levels can make a diff-
erence in grade. extra nitrogen at
the right time can he a good
investment. but how do you know
when the crop needs the nitrogen?
New hand-held chlorophyll
meters can take an instant measure
of crop N by reading leaf "green-
ness". The intensity of the green
indicates the amount of nitrogen,
since nitrogen is a component of
chlorophyll.
The Minolta SPAD 502 chloro-
phyll meter k like a big clothespin
you clamp around a leaf. It
concentrate, a light beam on a two
millimetre by three millimetre
sampling area. shining through the
leaf. The meter emits light in the
red and infrared region of the spec-
trum from a measuring arm placed
on the upper surface of the leaf.
Chlorophyll absorbs light
differently in these wavelengths.
The amount of light transmitted
through the leaf to the receiving
arm on the underside, is inversely
proportional to the amount of
chlorophyll at that spot on the leaf.
A greener crop has more N and
gives a higher reading.
The Minolta SPAD. worth
$2,000, was originally developed
to manage N in rice crops and has
since been successfully used in
grasses, corn, wheat and vegetable
crops, though readings on broad-
leaf crops tend to be more variable.
Another hand-held chlorophyll
meter, the Observer, bases its
readings on light reelection from
the leaf surface instead of
transmission through the leaf.
The main challenge in deciding
to apply extra N is to make sure
the crop chlorophyll content is due
to N status and not other factors.
Anything that interferes with the
plant's ability to produce
chlorophyll can affect meter
readings.°
— Source: Western Producer
Farming n a ,'a: ine
MAY 2001 53