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Developing and Implementing agricultural systems and practices
that maximize the potential for agriculture to mitigate global
climate change.
View photos of the project in our gallery.
Agriculture affects the condition of the environment
in many ways, including impacts on global warming through the production
of greenhouse gases (Robertson et al., 2000). In 2004, the US EPA
estimated that agriculture contributed approximately 7% of the U.S.
greenhouse gas emissions (in carbon equivalents, or CE), primarily
as methane (CH4) and nitrous oxide (N2O).
While agriculture represents a small but relevant source of greenhouse
gas emissions, it has the potential, with new practices, to also
act as a sink, tying up or sequestering CO2 from the
atmosphere in the form of soil carbon (Willson et al., 2001; Lal,
1999). Estimates of the potential for agricultural conservation
practices to enhance soil carbon storage range from 154-368 million
metric tons (MmtCE), which compare to the 345 MmtCE of reduction
proposed for the U.S. under the Kyoto Protocol (Lal et al, 1998).
Thus, agricultural systems can be manipulated for the dual benefits
of reducing greenhouse gas emissions and enhancing carbon sequestration.
Duxbury (1994) estimated that agriculture contributed
25% of the historical anthropogenic emission of CO2 during
the past two centuries. Soils store carbon for long periods of time
as stable organic matter, which reaches an equilibrium level in
natural systems determined by climate, soil texture, and vegetation.
When native soils are disturbed by agricultural tillage, fallow,
or residue burning, large amounts of CO2 are released
(Allmaras et al., 2000). However, a significant portion of this
carbon can be sequestered by soils managed with direct seeding and
other techniques. Irrigation can enhance carbon sequestration over
native soil levels by overcoming the moisture limitation to increased
plant biomass production.
Agriculture alters the terrestrial nitrogen cycle
as well. Through nitrogen fertilization, annual cropping, monocropping,
and improper water management, nitrogen is more prone to being lost
both to ground or surface water and the atmosphere. Nitrous oxide
(N2O), a common emission from agricultural soils, is
a potent greenhouse gas (296 times more than CO2) that
has increased its atmospheric concentration by 15% during the past
two centuries (Mosier, 1998). Reductions can be achieved through
improved nitrogen management, as well as with irrigation water management
because N2O is generated under both aerobic conditions
(where nitrification occurs) and anaerobic conditions (where denitrification
occurs) in the soil.
This 5-year project will focus on dairy
production, irrigated crop farming,
and dryland grain farming, three farming
systems of importance for Washington State and the world. The project
goals are as follows:
(1) assess the current situation regarding the
global warming contribution of three farm systems;
(2) develop strategies for changing the systems
to maximize global warming mitigation; and
(3) evaluate the actual and potential mitigation
through demonstration sites and computer
modeling.
The project approaches will include technology
research and development, socioeconomic
analysis and systems modeling, on-farm
implementation of demonstrations, and educational
outreach.
Key project tasks will include development of an
improved anaerobic digester for treating
dairy waste, development of whole farm nutrient management strategies
and an associated decision support system for dairy farms, integration
of reduced tillage and residue management to increase soil carbon
storage, irrigation water management to improve N cycling, and outreach
and education.
Expected impacts of the project include the documentation
of new technology, farm practices, and systems that can mitigate
multiple environmental problems and lead to measurable improvements
in greenhouse gas storage, water use, and nutrient cycling on farms.
Triple
BIOTM: BIOAg, Bioenergy and Bioproducts Program website
Dairy, Dryland,
Irrigated, Modeling,
Socio-Economic, Educational
Outreach
Updated
May 11, 2006
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