To provide a location in Western Canada determining whole-season and multi-year soil greenhouse gas budgets of cropping and management systems
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What are the Issues?
Our concerns about global climate change are caused by the observed and predicted increases in greenhouse gases in our atmosphere
The main greenhouse gases (GHG) of concern are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O)
Agriculture is responsible for about 10% of Canada’s total greenhouse gas emissions, but this includes more than half of the N2O emissions, and about 1/3 of the CH4 emissions
CH4 is mostly from livestock, but nitrous oxide is mostly from losses from fields associated with our need to apply fertilizers and manure to maintain productivity
N2O has a greenhouse gas potential that is 300 times more powerful than carbon dioxide
Reducing N2O emissions saves money and benefits the environment
Improved management of nitrogen such as spring application, banding, and slow-release products can reduce N2O emissions, but by how much?
Crop selection choices impacts soil C sequestration. Perennial crops may store carbon and when included in rotations allow creation of GHG neutral production systems
What are We Doing?
Quantify the emissions of N2O and CO2: how does the emission relate to climate, soil type, cropping system and form of nitrogen application?
Direct measurement method using tunable diode laser instrument: measure direct emissions from the field continuously.
Experiment has 4 very large plots being monitored since fall 2005. Annual plots have been in rotation of 2005-fallow, 2006-corn, 2007-faba, 2008-wheat, 2009-rapeseed, 2010-barley, 2011-wheat 2012-corn, 2013, soybean, 2014-wheat. The perennial plots have been in rotation of 2005-fallow, 2006-corn, 2007-faba, 2008 through 2011-alfalfa/grass and then into the same crops as the annual rotation.
Track GHG budgets and soil health during perennial phase (4 years) and conversion phase of perennial to annual cropping.
- Determine effect of anhydrous ammonia application in fall and spring on N2O emissions.
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What Will Be the Outcome?
Continuous measurements tell us what is really happening: N2O emissions are episodic with the high emissions occurring during fertilization and precipitation events, the annual rotation is losing carbon
But what are the biological processes controlling this, and can we change them?
Does spring fertilizer application reduce emissions?
Do perennial cropping systems reduce GHG emissions?
Does the benefit of perennial cropping carry into the conversion phase to annual cropping?
- This is the only site in western Canada where N2O and CO2 emissions are measured continuously from an agricultural field.
- Inclusion of the perennial legume forage reduced N2O emissions because of lack of synthetic fertilizer addition. Apparently, biological N fixation of the alfalfa of the order of 100-200 kg N ha-1y-1 did not produce N2O.
- Harvest removal of grain, straw, silage and hay resulted in net negative loss of C from soil. The losses are low (< 1 Mg C ha-1), but nevertheless show soils in the Red River Valley are not gaining or neutral losses of C.
- The perennial legume forage did help reduce the loss of C.
- The termination of the perennial legume forage resulted in accelerated loss of C from soil as CO2 emission thus some of the gain of C during the years of the forage was lost soon after transition to annual cropping.
Who Supports this Research?
- National Science and Engineering Research Council (NSERC) Discovery Grant Program, Canada Research Chair Program in Applied Soil Ecology, Canadian Fertilizer Institute, Manitoba Rural Adaptation Council, the AAFC Agriculture Greenhouse Gas Program.
- Canada Foundation for Innovation for NCLE
For more information, contact:
Dr. Mario Tenuta (Soil Science), 474-7827
Dr. Brian Amiro (Soil Science), 474-9155
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What is NCLE?
TGAS equipment in the field
Examples of results at the research site in 2006
The above figures show daily average fluxes of CO2 and N2O at the TGAS MAN site for March through October 2006. Positive values represent a net gaseous flux from the soil-crop system into the atmosphere, negative values represent net uptake by the crop system. Events occurring during the period affecting both gases are indicated.