Gulf of Mexico Hypoxia and the US Farm Bill

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Gulf of Mexico Hypoxia and the US Farm Bill
Could agriculture be different in the
future? Modeling Effects of Alternative
Landscape Design and Management on Water
Quality and Biodiversity in Midwest Agricultural
Watersheds. Santelmann, et al. EPA-NSF
R8253335-01-0.

Don Scavia Joan Nassauer University of
Michigan Mary Santelmann Oregon State
University Otto Doering Purdue University
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Scientific Assessment

• Hypoxic area is very large doubled since 1993
• Significant fishery resources are at risk

• River N load is main long-term driver of
  hypoxia
• N load is gt 3X that of 1950s
• Most N sources are agricultural non-point
• 90 of nitrate inputs from non-point sources.
• 56 of nitrate enters system north of Ohio
  River.

• Its possible to reduce loads by 40
• Economic flexibility helps

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Gulf of Mexico Hypoxia
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Area (km )
No Data
40
Rabalais, et al.
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Load Reduction Targets
20000
Model Analysis
15000
Ensemble Forecast
Area (km2)
10000
5000
0
10
20
30
40
50
60
Percent N Load Reduction
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Nitrogen Sources?
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Potential N ReductionOverall 40 reduction is
possible
0.05 (2)
0.3 (12)
0.3 (12)
0.9 (35)
0.02 (1)
0.5 (19)
0.5 (19)
Data Source Mitsch et al. 1999, 2001 CENR 2000
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Costs-effectiveness of Actions

• Unit Cost Net Cost
• /kg N /kg N
• Edge-of-Field Losses
• 20 0.88 0.80
• Precise Fertilizer Use
• 45 2.85 2.81
• Wetlands
• 5M acres 8.90 1.00
• Riparian buffers
• 19M acres 26.00
• Tertiary treatment 40

Doering et al
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How do we make it real? We looked at 3
alternative policy scenarios in two Iowa
watersheds.
Walnut Creek Flat and 5600 hectares 22 sq mi
Buck Creek Rolling and 8800 hectares 34 sq mi
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3 key ways to reduce loads
More efficient fertilizer inputs. Keep it on
the land
Remove it in wetlands
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• Compared with the present, the 3 alternative
  scenarios, shown in Walnut Creek, emphasized
• 1 Commodity production, or
• Comprehensive use of precision agriculture
• Increased area in corn-bean rotation by 8-38
• 2 Improved water quality, or
• Introduces pasture/alfalfa near fenced streams
• Widens stream buffers to 15 m
• Creates upland detention wetlands and off-channel
  wetland storage
• 3 Enhanced biodiversity
• Increased area in perennial grasses to more than
  20
• Widens stream buffers to 30 m
• Creates long-term wetland and upland bioreserves
  that detain run-off

Santelmann, et al. EPA-NSF R8253335-01-0.
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Corn/beans 86 Precision ag no-till Nitrate
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Corn/beans 60 Perennial strip, no-till,
bioreserve Nitrate -gt50
Scenario 1 production
Corn/beans/oats 56 Precision ag, no-till,
pasture Nitrate -gt50
Scenario 3 biodiversity
Scenario 2 water quality
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A team of 25 scientists compared and integrated
multiple measures and models of cultural,
ecological and economic performance.
Corn/beans 42 Perennial strip, no-till,
bioreserve Nitrate -gt50
Corn/beans 62 Precision ag no-till Nitrate
19
Corn/beans/oats 12 Prec. ag, no-till,
pasture Nitrate -gt50
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Water quality
Rank of the scenarios for
BEST
3
1
2
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Rank of the scenarios forMarket return to land
from production
BEST
1
3
3
15
Rank of the scenarios for
Biodiversity
BEST
1
2
3
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water quality, biodiversity, preference

BEST
3
1
Return to land
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• Changes in Corn Belt farming could dramatically
  reduce the
• 5000 square mile dead zone in the Gulf of
  Mexico.
• Agricultural policy could help to achieve these
  changes including
• More complete adoption of traditional and
  innovative conservation practices
• Precision farming
• Upland and wetland habitat restoration
• Perennial crops