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Reducing Climate Change and Water Quality Impacts from Grain Production on Maryland's Eastern Shore
Jon Winsten, Tom Fisher, Rebecca Fox, Anne Gustafson, Jim Lewis, Neville Millar
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Background• Crucial issues: Climate change and water quality • Nitrous oxide (N2O) has 310 times the radiative
forcing of carbon dioxide (CO2) • N2O is 7% of U.S. GHG emissions
– 73% is from agriculture • Agriculture is the leading source NPS pollution
to ground and surface waters in the U.S.
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Background• Feeding 9 billion people by 2050.• Regulations decrease productivity and increase
costs.• Environmental markets provide prices for
“externalities” and can result in efficient outcomes.
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Choptank River Watershed
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Research Site
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Research Treatments• Winter cover crops• Reduced N rate (80% of UMD recommendations)• Conservation rotation
– 80% N rate on corn – 80% N rate on winter wheat– Soybeans– Barley cover crop
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Nitrous Oxide Sampling
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Nitrous Oxide Sampling
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Water Quality Sampling
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Water Quality Sampling
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Nitrous Oxide Sampling ScheduleTreatment: 80% N on Corn
date purpose20130129 winter fluxes
20130225 winter fluxes
20130408 spring fluxes prior to biosolids
20130513 3 days after biosolids
20130517 7 days after biosolids
20130530 7 days after planting corn, starter
20130614 10 days prior to side-dress
20130627 3 days after side-dress
20130702 8 days after side-dress
20130709 15 days after side-dress
20130828 2 weeks prior to harvest
20131007 3 weeks following harvest
20131106 7 weeks following harvest
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Nitrous Oxide Sampling
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Results: Winter Cover Cropping
22 3.7lbs N acre-1 (Nov-Mar)
36 32lbs N acre-1 (Dec-Mar)
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Results: Reduced N Rate
45 29lbs N acre-1 (Nov-Mar)
32 30lbs N acre-1 (Dec-Mar)
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Costs and Revenues
• Cover Crops– Potential Revenues
• Conservation payment: $70/ac• Carbon credits: 1MT CO2e/ac @ $10/MT = $10/ac• WQ credits: 10 lbs N/ac @ $5/lb = $50/ac
– Costs• Seed: $40/ac• Planting: $8/ac• Herbicide: $14/ac
– Profit = $130 - $62 = $68
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Costs and Revenues
• 80% N Rate– Potential Revenues
• Carbon credits: 0.2MT CO2e/ac @ $10/MT = $2/ac• WQ credits: 8 lbs N/ac @ $5/lb = $40/ac
– Costs• Fertilizer: saved 40lbs N/ac @ $0.52/lb N = -$20.80• Yield loss: 30 bushels/ac @ $3.75/bu = $112.50
– Profit = $42 - $91.70 = $-49.70
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Initial Conclusions
– Dry Year:• Cover crops reduced fall N2O fluxes winter/spring
tile drain NO3
• Reduced N rate reduced N2O and NO3 and did not affect yields
– Wet Year:• Cover crops did not reduce N2O, but did reduce
NO3• Reduced N rate lowered yields and had minimal
effect on N2O and NO3
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Future Work
– Use measurement data to cal/val simulation models
– Use models to estimate impacts for farmers in Eastern Shore region
– Facilitate farmers’ transactions in environmental markets
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