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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
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Agronomic and EnvironmentalBenefits 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
Agriculture as an Emitter of Greenhouse Gases • Canadian agricultural GHG emissions in 1996 = 64 million tonnes (9.5%)
Why manage carbon in Manitoba? Soil Quality GHG Emission Reduction Air Quality Sustainability Profitability Water Quality
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 HoldingCapacity Soil Structure Soil Biodiversity Root Growth Nutrient Reserves Crop Yield Water Storage Reduced Soil Erosion Soil Pathogen Control Soil Organic Matter Water Access Fertility Profit!
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 carbonate-rich 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
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 Rationale for Prairie/Parkland:
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 (Note: 1 Tg = 1012 g) (Houghton 1990, Davidson 1991, Bartlett and Harriss 1993)
Methane emissions in wetlands by latitude A+C: Aselmann and Crutzen M+F: Mathews and Fung Peatlands Wetlands N S N S 96-135 mg m-2 d-1 48-63 mg m-2 d-1 (from Bartlett and Harriss 1993)
Quantify carbon storage along wetland-riparian-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 Link to national scaling-up studies underway in the agricultural sector Develop a carbon model specific to wetlands and riparian areas Research Objectives:
300 Field Pond 120 Pond 117 250 Upland soils Wetland soils 200 Transition soils 150 Soil Organic Carbon (Mg ha-1, 0 to 60 cm) 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