Agriculture Reference
In-Depth Information
Similarly, atmospheric nitrogen deposition also
affects crop production systems as well as chang-
ing temperature regimes, although the effect will
depend on the magnitude of change and response
of the crop, forage, or livestock species. For
example, increasing temperatures are likely to
have a positive effect on crop production in colder
regions due to a longer growing season (Smith
et al.
2005
). In contrast, increasing temperatures
could accelerate decomposition of soil organic
matter, releasing stored soil carbon into the atmo-
sphere (Smith et al.
2005
). Furthermore, changes
in precipitation patterns could change the adapt-
ability of crops or cropping systems selected to
reduce GHG emissions. Many of these effects
have high levels of uncertainty; but demonstrate
that practices chosen to reduce GHG emissions
may not have the same effectiveness in the com-
ing decades. Consequently, programs to reduce
emissions in the agricultural sector will need to
be designed with fl exibility for adaptation in
response to climate change.
Overall, the outlook for GHG mitigation in
agriculture suggests signifi cant potential. Current
initiatives suggest that identifying synergies
between climate change policies, sustainable
development, and improvement of environmental
quality will likely lead the way forward to real-
ization of mitigation potential in this sector.
The organic and sustainable farming systems
can and must play an important role in addressing
climate change. These systems have been proven
to help farmers and ranchers reduce GHG
emissions and increase storage of carbon in agri-
cultural soils. These systems can also increase
the resilience of their farming and ranching oper-
ations to deal with the climatic changes that
appear likely under global warming scenarios.
They are also the best systems for minimizing
other conservation and environmental impacts
from agricultural production.
Major points from the research considered in
this chapter are the following:
• Protecting grassland and pasture-based agri-
cultural systems and converting row crop sys-
tems to grass-based systems can provide for
signifi cant levels of retained and newly
sequestered soil carbon.
• No-till likely does not sequester new carbon in
the soil. The establishment of sustainable and
organic systems that include use of cover crops
and green manures and conversion from annu-
als to perennials for pastures and grassland
systems will increase carbon sequestration.
• High levels of synthetic fertilizer can reduce
soil carbon as well as increase NO
2
emissions.
Sustainable and organic systems reduce or
eliminate synthetic fertilizer use through the
use of nitrogen-fi xing plants in rotations, use
of green manures and biofertilizers, and use of
animal manures integrated into cropping sys-
tems or as part of intensively managed rota-
tional grazing systems. These systems can
also retain more nitrogen in soils, reducing
nitrogen runoff and leaching which also con-
tribute to NO
2
emissions.
• Sustainable and organic livestock production
systems that include pastures, perennial for-
ages, and the effective management, compost-
ing, and incorporation of manure can
signifi cantly lower methane emissions from
livestock production.
• Sustainable and organic agricultural systems
provide for better management of water, con-
trol soil erosion, and provide conservation
benefi ts in addition to the reduction of GHG
emissions that can increase the environmental
and economic resilience of farming systems
and better enable farmers to cope with rapid
climate change.
• Farmers and ranchers have signifi cant oppor-
tunities to lower energy use on-farm and to
generated on-farm energy, especially solar
and wind power. On-farm biofuel production
can be based on incorporation of perennial
feedstocks or new crops in resource-
conserving crop rotations that can result in
overall reduction of net GHG emissions from
the farm or ranch.
• The sustainable and organic systems that
result in lowered GHG emissions and
increased carbon sequestration also provide
signifi cant conservation and environmental
benefi ts and increase the overall health of soils
which can increase agricultural production as
well.
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