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  • From: "Rick Williams" <mrfarm AT frontiernet.net>
  • To: "Marketfarming" <market-farming AT lists.ibiblio.org>
  • Subject: [Market-farming] A Ross Gould post
  • Date: Thu, 13 Feb 2003 16:05:25 -0600

Ross posts quite a bit on Graze-L and many posts would not be that connected
to market farming. But here is one that is probably the number one issue in
the world in terms of why grazing is so important, including rangeland. This
is something that we will probably incorporate into our web site as yet
another benefit of grazing.

Good Afternoon List Friends,
This is a release from the Lethbridge Research Centre, sent out by
Meristem an ag communications service here in Calgary. It emphasizes the
role of rangelands as "a massive storehouse in the global carbon cycle."

They point out that, " Grazing regimes can also have a significant
effect on soil carbon storage" so grazing land management can play an
important part in reducing greenhouse gasses.

Regards
Ross Gould, P.Ag.
Calgary, Alberta

********************************************************
LETHBRIDGE RESEARCH CENTRE
P.O. Box 3000, Lethbridge, Alberta, T1J 4B1
Phone: (403) 327-4561 Fax: (403) 382-3156
Email: lethbridge AT agr.gc.ca
Web site: www.agr.gc.ca/science/lethbridge
********************************************************

Western rangeland plays hidden role as massive carbon storehouse

Lethbridge, Alta., Feb. 13, 2003: Western Canada's vast tracts of
rangeland play a crucial part
in ranching, oil and gas exploration, wildlife management and
recreation. But one of this
land's most important roles remains largely hidden - that as a massive
storehouse in the global
carbon cycle.

Though the region's native grasslands have only modest above-ground
vegetation, it's important
to remember that underfoot they house billions of tonnes of organic
carbon, say scientists at
the Agriculture and Agri-Food Canada (AAFC) Lethbridge Research Centre.
Managing these reserves
effectively can play a key role in controlling global emissions of
carbon dioxide - the chief
greenhouse gas targeted by the Kyoto Protocol.

"Increasing concentrations of carbon dioxide in the atmosphere continue
to focus increasing
attention on the global carbon cycle," says Dr. Henry Janzen, research
scientist in nutrient
cycling. "Grasslands, because of their expanse and high carbon density,
are a prominent part of
that cycle, both globally and in Canada. Probably their greatest role is
as a repository of
carbon already stored. And the grassland management practices that have
greatest benefit to the
atmosphere are those which hold these large reserves in place."

The AAFC Lethbridge Research Centre has several long-term studies in
place to examine changes
in soil carbon under various types of land use, and has helped
co-ordinate AAFC's greenhouse
gas initiative since it began in 1992.

Soil organic matter, says Janzen, contains approximately double the
amount of carbon currently
in the atmosphere. As a result, even a small shift in soil organic
matter can have a large
impact on atmospheric carbon dioxide.

"The soils in temperate grasslands contain more carbon per unit area
than those of most other
ecosystems, worldwide. For example, a soil under grassland in Western
Canada may contain, to
one metre depth, up to 200 tonnes of carbon per hectare in the black
soil zone under fescue
prairie," he says. "If soil organic matter is depleted through
mismanagement, the carbon lost
from the soil finds its way into the atmosphere as carbon dioxide.
Conversely, practices that
build up soil carbon remove carbon dioxide from the air."

Over the past century, cultivation and other soil-depleting practices
have resulted in the loss
of roughly one-half to 1 billion tonnes of carbon from Canadian prairie
soils. "But the
uncultivated grasslands of Western Canada still contain large reserves
of carbon. Keeping the
plow away is by far the best way for rangeland producers and managers to
keep this carbon in
store and help slow atmospheric carbon dioxide increases."

Grazing regimes can also have a significant effect on soil carbon
storage, he says. "The most
practical management option for increasing soil carbon storage may be to
alter the grazing
intensity, timing or frequency. Grazing regimes can alter the plant
community, favouring some
species over others. They can also affect plant residue, plant vigour
and other important
factors."

Further research is needed to pinpoint the best grazing strategies that
favour soil organic
matter, he says. A challenge for researchers is the complexity of native
grassland systems
compared to monoculture arable systems. "Some studies have even
suggested higher soil carbon
storage under well-grazed than under non-grazed treatments. More
long-term studies on diverse
grasslands are still needed to evaluate these and other opportunities."

Clear opportunities do exist, however, on economically or
environmentally marginal land, and on
over-grazed grassland, he says. Re-establishment of perennial grass in
these areas could
eventually result in the recovery of carbon previously lost.

Soil carbon research at Agriculture and Agri-Food Canada's Lethbridge
Research Centre
illustrates the government's commitment to promote innovation for
growth, maintain the security
of the food system and protect the health of the environment, as
proposed in the new
Agricultural Policy Framework. The Framework aims to increase
profitability for producers by
giving them the tools and capabilities to respond to constantly changing
consumer demands for
safe food produced in an environmentally responsible way.
-30-
For more information, contact:

Dr. Henry Janzen
Research Scientist, Nutrient Cycling
Phone: (403) 317-2223

John Calpas, Communications Co-ordinator
Phone: (403) 317-2262
Lethbridge Research Centre, Agriculture and Agri-Food Canada
Phone: (403) 327-4561
Web site: www.agr.gc.ca/science/lethbridge

Acknowledgement: Communication sponsored in part by
The Canada Alberta Livestock Research Trust Inc.



  • [Market-farming] A Ross Gould post, Rick Williams, 02/13/2003

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