On-farm Greenhouse Gas Mitigation Practices
Julie DollW.K. Kellogg Biological Station &
Dept. of Plant, Soil and Microbial SciencesMichigan State University
Paustian et al., 2006
On-farm “Climate Smart Agriculture”
Julie DollW.K. Kellogg Biological Station &
Dept. of Plant, Soil and Microbial SciencesMichigan State University
Paustian et al., 2006
On-farm “Climate Smart Agriculture”
Julie DollW.K. Kellogg Biological Station &
Dept. of Plant, Soil and Microbial SciencesMichigan State University
Paustian et al., 2006
Roadmap
• Three biogenic greenhouse gases• Mitigation practices on the farm – field crops• Systems approach
The three major biogenic greenhouse gases- are all affected by agriculture
(Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2013, EPA 2015)
U.S. greenhouse gas emissions in 2013(carbon dioxide-equivalents)
Global Warming Potential: combined effect of atmospheric lifetime and ability to absorb heat• Carbon dioxide (CO2) GWP = 1• Methane (CH4) GWP = 23• Nitrous oxide (N2O) GWP = 296
Carbon dioxide-equivalents: units that represent the relative impact of a gas on atmospheric warming
Agricultural emissions in the United States
(EPA’s US GHG Inventory Report, 2014)
Does not include land cover change or other aspects of the food system, such as transportation.
Mitigation
(WICCI, 2011)
The idea that we can avoid, prevent or minimize undesirable things happening in the future.
1. Release fewer greenhouse gasesto the atmosphere
1. REMOVE greenhousegases from the atmosphere
Cropland in the U.S.
(Adapted from USDA, 2014)
(Robertson et al., 2015)
Importance to farmers of environmental benefitsprovided by agriculture
N=1800 Michigan corn-soy farmers. (Jolejole 2009; Lupi 2009)
Co-benefits of mitigation practices
• Stewardship goals
• Saving money
• Improving yields
• Increasing resilience to climate variability
• Adapting to climate change
Carbon dioxide (CO2) sources in the U.S.
(Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2013, EPA 2015)
Mitigating carbon dioxide on the farm
• Whole farm energy use• Fertilizer production (Haber-Bosh process)• Other farm inputs (lime, pesticides, seeds)
Technologies and practices to mitigate• Improve electric service systems in rural areas• Energy efficiency improvements• Renewable energy generation
(USDA Building Blocks)
Mitigating carbon dioxide on the farm
• Soil carbon storage and conservation (“carbon sink”)
• 40-60% of original soil carbon lost after 40-60 years of cultivation in our region of North America
How to restore soil carbon?
1. Increase carbon inputs to soil
2. Decrease carbon loss from soil (slow decomposition)
•Cover crops•Rotations•Residue management
•Reduce tillage•Residue quality
Annual Crops (Corn - Soybean - Wheat)Conventional tillageNo-tillReduced-input with legume & rye cover cropsOrganic with legume & rye cover crops
Unmanaged FieldsEarly successional “old field”
Kellogg Biological StationLong-term Ecological Research (KBS LTER)
ChemicalIntensity
HIGH
LOW
(www.lter.kbs.msu.edu)
Restoring soil carbon – KBS cropping systems 12 years after establishment
(Syswerda et al., 2011)
Potential for recovering soil carbon
(Lal 1999, Smith 2004, IPCC 2002, Grace et al. 2006)
Eight years of accumulated C from CRP land is lost with a single tillage event
(Ruan and Robertson 2013)
But stored soil carbon is vulnerable to loss!
Methane (CH4) sources in the U.S.
(EPA, 2014)
Mitigating methane on the farm
Reduce production(methanogenesis):
Increase consumption(oxidation):
Mitigation technologies and practices:• Anaerobic digesters • Lagoon and waste storage covers with flaring• Enhanced solid separation
(USDA Building Blocks)
Nitrous oxide (N2O) sources in the U.S.
(EPA, 2014)
Inorganic NITROGEN
Nitrous oxide
Microbial processes: nitrification & denitrification
0
50
100
150
200
250
300
May Jun Jul Aug Sep Oct Nov
g N
2O-N
ha-
1 d-1 CT
NTrain
rain
rain
raintillage
sidedress N
planting N
Continuous corn
(Ruan & Robertson 2013)
Fertilizer and rainfall are drivers of N2O emissions
Nitrous oxide has a nonlinear response to N fertilizer
(Adapted from Millar and Robertson, 2015)
Yields do not increase beyond an N rate threshold
(Adapted from Millar and Robertson, 2015)
(Adapted from Millar and Robertson, 2015)
Environmental credit: tons of CO2-equivalents per acre
Reducing N2O emissions while maintaining yields
• Reduces agricultural greenhouse gases• Reduces reactive nitrogen in environment (including nitrate)
Current Status• Protocol now registered• Being marketed by aggregators• First credit issued June 2014 to
Michigan farmer Myron Ortner, then sold to the Climate Trust
Paying farmers for mitigation:MSU-EPRI Nitrous Oxide Reduction Protocol
(Millar et al., 2012, 2013)
Pays farmers for applying nitrogen fertilizer more precisely (4 “R’s”)
http://www.deltanitrogen.org
Ryan Smith: [email protected]
A systems approach to greenhouse gas mitigation on the farm
Paustian et al., 2006
NPKLimeFuelSeedsPesticidesN2O
SOC
Ecosystem
Conventional No-till Low-input Biological-200
-150
-100
-50
Glo
bal W
arm
ing
Impa
ct (g
CO2e
q m
-2 y
r-1)
0
20
40
60
80
100
120
(Gelfand and Robertson, 2015; Gelfand et al., 2013)
Global warming impact of agricultural practices at KBS
Contributes to climate change
Mitigates climate change
Conventional No-till Low input OrganicConventiona
(Robertson et al., 2015)
Net global warming impact of KBS cropping systems
Contributes to climate change
Mitigates climate change
Organic
ReducedInput
No-till
Conventional
USDA Resources: Greenhouse gas report
(Eve et al., 2014)http://www.usda.gov/oce/climate_change/estimation.htm
USDA Resources: COMET-Farm
(Eve et al., 2014)
http://cometfarm.nrel.colostate.edu
Combining a landowners’ crop, livestock and forest management activities into a seamless greenhouse gas estimate for the entity.
Summary
1. Carbon dioxide mitigated (soil carbon stored) by:• Permanent no-till• Cover crops
2. Nitrous oxide mitigated by:• Any “4R” practices that reduce nitrogen inputs
• Better fertilizer recommendation• Variable rate application• Spring (not fall) fertilizer application
• In the future: nitrification inhibitors
Summary, con’t
3. Systems approach to mitigation helpful– Shows tradeoffs
4. Mitigation on the farm = climate smart agriculture = smart agriculture
– Co-benefits to mitigation: adaptation and resilience
Thanks!
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