The Rural Voice, 2003-12, Page 18Advanced study
Speakers give farmers the facts about manageing manure
from the feed to the field at Shakespeare conference
By Keith Roulston
Lessons in managing nutrients,
from how you feed pigs to
how you store manure to what
happens when it goes on the field
were delivered at a seminar in
Shakespeare, November 19.
Speakers from as far away as
Denmark brought their expertise to
the Nutrient Management: And Now
the Rest of the Story conference.
Keynote speaker Jens Bo Holm -
Nielsen, for instance gave producers
a picture of where things could be
heading if Ontario follows the course
already set out in Denmark. Head of
the Bioenergy Department, Centre of
Industrial Biotechnology and
Bioenergy, at the University of
Southern Denmark and Aalborg
University, Holm -Nielsen explained
that in the past 15 years Danish
farmers have faced water action plans
from the Danish Parliament as it tried
to protect the fresh water of rivers
and the ground water from the 46
million tons of liquid manure applied
to farmland in a country with only
45,000 square kilometers of land and
a huge shoreline. Denmark, with a
population of 5.5 million people,
sends 23 million hogs to market
every year.
Farmers are only allowed to apply
manure to crops from March 1 to
August 1 each year. Autumn
application is only allowed on grass
or winter oil seed crops. In manure
from cattle, 60 per cent of nitrogen
must be taken up by the crop in the
first year, and for pigs it is 65 per
cent.
There are also concerns about
ammonia escape into the air.
Research has shown 34 per cent of
this escape comes from barns, 20 per
cent from field application and 17 per
cent from storage. But the Danes
have found that by reducing the
protein content of feed to market
hogs, they can nearly half the
nitrogen loss. This cut in ammonia
production improves the air quality
in barns bringing better health to both
animals and workers and can reduce
14 THE RURAL VOICE
Jens Bo Holm -Nielsen tells Ontario farmers
about situation in Denmark.
ammonia loss all the way to the field.
On the other hand, it can mean more
chemical nitrogen fertilizer must be
applied to fields to get the same
boost for crops.
And the value of manure as
fertilizer is not overlooked in
Denmark where farmers replace most
of their chemical fertilizer inputs
with manure. The value of nitrogen,
phosphorous and potassium from
manure is put at $200 million
Canadian a year.
Within the barn, ammonia
evaporation from deep straw bedding
is higher than from untreated liquid
manure, with digested slurry from
biogas production and separated
liquid fraction lower still. To reduce
ammonia evaporation Danish
research shows you should reduce the
surface area of the liquid manure as
small as possible, get the manure into
the soil as quickly as possible and
have a good cover crop. Thick slurry
with a high pH value promotes loss
of ammonia.
Best nitrogen utilization comes
from liquid fraction slurry followed
by the end -product of biogas
production. Liquid pig manure has
better take-up than liquid cattle
manure. Deep straw bedding trails in
the uptake of its nitrogen content.
Production of biogas plays an
increasingly large part in the manure
treatment process in Denmark with
five per cent of all manure going
through digesters. About 50 large-
scale farms have on-farm digesters.
In other cases about 20 large
centralized biogas plants have been
set up with manure from surrounding
farms trucked or piped in. In one
case, 100 farmers on an island have
invested the equivalent of $15
million Canadian in a centralized
plant to solve concerns about
pollution.
Often the gas from the larger
biogas plants goes to heat nearby
urban centres. To increase the yield
of the biogas process they take food
wastes with a higher carbohydrate
content from other sources — up to
20-25 per cent of the volume. Fats
added to the manure can double gas
production.
The use of these additional food
wastes also makes them available to
spread on fields in a safe way at the
end of the digestion process.
Digestion creates a disease and
weed -seed free fertilizer with Tess
odour.
The European Union has set a
goal of 12 per cent of its
energy from renewable sources
by 2010 so there are incentives for
farmers to get into biogas production.
The future seems to be pointing
toward an integration of biogas
production into the European gas
grid as well as biogas for fueling
buses and using biogas in fuel cells.
Danish farmers are getting eight
cents per kilowatt hour for electrical
power produced from biogas-fueled
generators or wind power. By
contrast retail electrical rates in
Ontario were frozen at 4.6 cents by
the Eves government in Ontario.
Holm -Nielsen said Ontario
farmers should be looking ahead at
the possibilities of biogas,
particularly in southwestern Ontario
where there are large concentrations
of hog operations but he warned