Agronomic and Environmental
Benefits of Managing Carbon
Rhonda L. McDougal, Ph.D.
Institute for Wetland and Waterfowl Research
Ducks Unlimited Canada
Carbon management will not
occur in isolation.
• Farmers manage for production, profit, and
long-term sustainability of the resource
• Conservationists manage for healthy intact
ecosystems, biodiversity, and preservation of
the resource
• Managing for carbon in Manitoba landscapes
must enhance these goals
Agronomic?
• Management practices that promote
agricultural efficiency and make economic
sense, measured in terms of profit, land
stewardship, and long-term sustainability on
the landscape
Environmental?
• Management practices that promote
environmental health, measured in terms of
air, soil and water quality, and preservation of
biodiversity and wild spaces on the landscape
Agronomic and Environmental?
• Landscape-scale management practices that
incorporate considerations of environmental
health within land stewardship and make
economic sense for agricultural and
conservation land managers
• Can carbon management in Manitoba be a
win-win situation for agriculture and the
environment?
Why manage carbon in Manitoba?
• Increasing the carbon sink capacity of
biological sinks (e.g. soils, forest biomass,
prairie wetlands(?)) will provide a “stop-gap”
reduction in net greenhouse gas emissions,
allowing other sectors time to develop new
technologies to reduce GHG emissions
directly.
• Carbon sinks may equal carbon credits for
land-owners (a direct economic benefit)
Why manage carbon in Manitoba?
Manitoba is a low emitter of GHGs
260
240
220
200
180
160
140
120
100
80
60
40
20
0
Atlantic
QC
ON
1990
MB
2000
2010
SK
2020
AB
BC
Agriculture as an Emitter of
Greenhouse Gases
– Canadian agricultural GHG emissions in
1996 = 64 million tonnes (9.5%)
CO2 ~ 3%
N2 O ~ 61%
CH4 ~ 36%
Why manage carbon in Manitoba?
Soil
Quality
GHG
Emission
Reduction
Air
Quality
Water
Quality
Sustainability
Profitability
Agronomic and Environmental Benefits of
Managing Carbon
• Increased soil health for higher productivity
• Increased control over pesticide fate and
decomposition
• Decreased soil erosion
• Decreased compaction and decreased
likelihood of water run-off
• Decreased inputs (less fuel use, more
uniform application of N and P fertilizers and
pesticides, therefore more efficiency)
Agronomic and Environmental Benefits of
Managing Carbon
• Decreased inputs (nutrients, soil, pesticides)
to adjacent ecosystems (riparian areas,
wetlands, rivers)
• Increased areas of grassland, therefore
increased health of riparian areas and buffer
strips
• Decreased incidence of bathtub-ring salinity
• An economic and environmental reason to
maintain prairie wetlands in farm fields and to
restore some drained wetlands?
Soil Organic Matter - The Record
• SOM levels have
declined since
cultivation
• Alternate
management may
result in soils of
higher SOM content
– C sequestration
– Requires inputs
• Net GHG
impact?
Water
Water
Holding
Storage
Capacity
Reduced
Soil
Soil
Structure
Erosion
Soil
Soil
Pathogen
Biodiversity
Control
Soil
Organic
Matter
Root
Water
Growth
Access
Nutrient
Fertility
Reserves
Crop
Profit!
Yield
Enhancing the Stability of “Fixed” C
• Agricultural
Management
Options
– Tillage systems
– Harvest & use
• Food vs. Fiber
– Land use change
– Erosion control?
Tillage Erosion and Carbon Dynamics
• In rolling and hummocky landscapes,
organic-rich topsoil is lost from the hilltops
and carbonate-rich subsoil is exposed.
• The exposure and acidification of carbonaterich subsoil material on upper slopes
increases CO2 emissions from inorganic
carbon sources in these landscapes
• Inorganic carbon processes may be equal in
importance to organic carbon processes
Agricultural Soil C sequestration
• Enhanced soil quality
• Verifiable sink?
• Permanence of the sink?
– Who has long-term responsibility/liability
• Value?
– Will the value of a C sink be sufficient to interest
farmers?
Investing in the Carbon
Sink Potential of
Agriculture and Wetland
Sustainability
Finding a Natural Solution
Agriculture & Wetlands Greenhouse Gas Initiative – Ducks Unlimited Canada
Research Collaborators:
Agriculture and Agri-Food Canada
Canadian Wildlife Service (EC)
Ducks Unlimited Canada
National Water Research Institute (EC)
University of Alberta
University of Manitoba
University of Saskatchewan
Alberta Agriculture, Food and Rural Development
Agriculture & Wetlands Greenhouse Gas Initiative – Ducks Unlimited Canada
Rationale for Prairie/Parkland:
Focus is on wetlands and riparian areas within the
context of agricultural land-use
- an integrated landscape approach
Net balance between carbon storage and
greenhouse gas flux in Prairie wetlands is unknown
- knowledge gap
Prairie wetlands are biologically different systems
than peat lands and agricultural lands, the two
“proxies” currently being used to estimate wetland
net carbon balance
Prairie Wetlands as Carbon Sinks?
• High primary productivity
• Reduced decomposition (anaerobic, cold)
• Pristine wetlands store two to five times as
much carbon as farmed wetlands
• Reduced methane emissions due to methane
oxidation (role of algae, plants,
methanotrophs)
• Low nitrous oxide levels
Wetland contributions to global annual
greenhouse gas emissions
GHG
Wetland
(Tg yr-1)
Global
(Tg yr-1)
%
Contribution
CO2
8.5
7000
0.12
N2O
0.1
7.1 to 12.7
0.8 to 1.4
CH4
113
540
21
(Note: 1 Tg = 1012 g) (Houghton 1990, Davidson 1991, Bartlett and Harriss 1993)
Methane emissions in wetlands
A+C: Aselmann and Crutzen
by latitude
M+F: Mathews and Fung
Peatlands
18
A+C
M+F
CH4 Flux (Tg yr-1)
16
14
14
12
10
10
8
8
6
6
4
4
2
2
N
85 75 65 55 45
35 25 15
5
5
15 25
Latitude (10 degree bands)
96-135 mg m-2 d-1
35 45
A+C
M+F
16
12
0
Wetlands
18
S
0
N
85 75
65 55
45 35
25
15
5
5
15 25 35 45
S
Latitude (10 degree bands)
48-63 mg m-2 d-1
(from Bartlett and Harriss 1993)
Research Objectives:
Quantify carbon storage along wetlandriparian-upland transects across the PPR
Quantify greenhouse gas flux (CO2, CH4, and
N2O) along same transects
Identify and measure key ecological drivers that
control changes in C and GHG flux along these
transects
Assess spatial and temporal variability of GHG
fluxes in heterogeneous wetland zones and
riparian areas
Research Objectives:
Identify impacts of agricultural upland
management on C storage and GHG flux in
wetlands and riparian areas
Identify impact of tillage through wetland basins
on GHG emission and C storage during drought
years
Assess the effect of wetland restoration (over
time 0-15 yrs, and over climatic gradient of PPR)
on C storage and GHG emission
Develop a carbon model specific to wetlands and
riparian areas
Link to national scaling-up studies underway in
the agricultural sector
Soil Organic Carbon (Mg ha-1, 0 to 60 cm)
300
Field
250
Pond 117
Pond 120
Upland soils
Wetland soils
200
Transition soils
150
100
50
0
DS
DBS
DFS
TP
GE
ST
GE
Mid
CF
CS
CBS
CFS
Mid
CF
TR
ST
Landscape Element
Acknowledgements
•
•
•
•
•
David Burton, University of Manitoba
David Lobb, University of Manitoba
Dan Pennock, University of Saskatchewan
Ken Belcher, University of Saskatchewan
Marie Boehm, AAFC