The Rural Voice, 2001-11, Page 40Research Scrap Book
U. of G. researcher investigates biosolids
Amid the controversy over the
application of processed sewage, also
known as biosolids, to farm fields, a
University of Guelph researcher, is
studying how metals in the material
are absorbed by plants and soil.
Land Resource Professor Beverley
Hale, along with Murray McBride of
Cornell University in New York, is
testing to see if levels of such metals
as cadmium, lead, copper, nickel and
zinc are higher than normal after •
sewage biosolids have been spread on
the land surface. Metals in foods can
pose a risk to human health, says
Hale.
About half of Ontario's 300,000
dry tonnes of treated sewage is spread
on land each year while about 40 per
cent is incinerated and 10 per cent
goes to landfills. The high cost of
landfills and incineration. plus
concerns over polluted air from
incineration, have made land
application more popular.
Popular, that is, except for
neighbours in areas where the
biosolids are spread, who worry about
danger from metals in the materials.
These concerns led to Hale's research.
She's examining the metal uptake
by beet roots and chard in test fields at
the university's Elora and Cambridge
Research Stations after sewage
biosolids have been applied. Beet root
is a test subject because the edible
portion is in direct contact with soil
and it's the part most likely to absorb
metals first. Chard was chosen
because green leafy vegetables have
been known to bioaccumulate heavy
metals. Hale's experiments are
looking at an extreme case. Sewage
biosolids are being applied at twice
the allowable levels set by the Ontario
Ministry of the Environment.
The two experimental sites were
chosen for their different soil types:
the Elora site is composed of silt loam
soil, while the soil at the Cambridge
site is sandy. Hale believes metals
might leach more quickly from sandy
soil, which has less organic material,
than from soils with higher organic
content.
Most previous studies looking at
metal uptake by plants measured the
metal content in plants immediately
after the application of biosolids. Hale
thinks metal bioavailability changes
with time after biosolids application
because soil pH changes and organic
material decomposes. Because of
these changes over time, she is
looking for any differences in plant
metal uptake on soils where biosolids
were applied every spring and on land
where biosolids were spread more
than 20 years ago.
She is also studying how much of
the metals are bound to the organic
portion of soil and how much
dissolves in the soluble portion. The
chemical form and location of metals
in the soil play a role in determining if
and how much metals leach from soil
as well as the metals' availability to
plants.0
— Source: University of Guelph's
Agri food Research in Ontario
Problem weed could become a cashcrop
Milkweed, that hardy weed that's the plague of row -crop farmers, could be
turned into a cash crop thanks to a Nebraska company.
Natural Fibers Corp. has found many uses for the perennial weed, including
mixing the fibres with goose down to create light and fluffy, hypoallergenic
pillows and comforters. A subsidiary, Ogallala Down, last year sold $1.4 million
U.S. worth of those bed products to specialty stores and the Four Seasons hotel
chain. Milkweed fibres also are being studied as a way to improve sound quality
in stereo speakers and oil from the plant's seed is being developed by cosmetic
companies as a skin moisturizer. Pressed seed cake from milkweeds is showing
promise as a natural control of potato nematodes. Natural Fibres Corp. also sells
milkweed plants as a perennial to butterfly farms and state highway departments
for beautification and reclamation projects.
Ironically an obstacle to turning milkweed into a cashcrop is getting the seeds
to germinate, promoting uniform growth and warding off fungal disease.0
— Source: Associated Press
38 THE RURAL VOICE
Research could improve
manure spreaders
Research by a Kemptville
College professor could lead to a
solid manure spreader with a lower
and more even rate of manure
application.
Prof. Ben Hawkins is redesign-
ing the chopping and spreading
action of solid manure spreaders in
an effort to eliminate problems
related to ground and surface water
that are more likely to occur when
high and uneven rates of manure
are applied during periods when
plant requirements of nutrients are
low.
Hawkins tested three or four
conventional spreaders and found
they delivered the manure in a path
equal to their width, limiting how
fast manure can be unloaded. The
spreaders were unable to break up
the larger clumps of manure. poss-
ibly leading to an uneven spread
and the smothering of crops.
He is developing a spreader
with a more efficient chopping
action and an increased range of
spread, to ensure that animal
wastes and biosolids are applied to
the land at timely rates. Increasing
the width of the spreader would
allow farmers to spread manure at
a lower rate of application but still
get manure onto the land at the
same speed.
Hawkins is examining other
machinery in addition to
conventional spreaders, such as
chopping and feeding devices, to
get ideas of how to redesign the
manure spreader. The design of the
chopping stage of the spreader has
been completed and the prototype
is being built for testing later this
year. He is designing the spreader
stage and plans to have its
construction completed by the end
of the year. More testing will be
carried out next spring.
Hawkins is also investigating
treatment methods for manure that
will produce a more uniform
product that can be spread more
evenly on the land.0
— Source: University of Guelph's
Agri food Research in Ontario