Iowa Conservation Practices:

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Iowa Conservation Practices Historical
Investments, Water Quality, and Gaps
Presentation prepared for the Iowa Farm Bureau
Conservation and Environmental Issues Conference,
June 28, 2006 H. Feng, P. Gassman, M. Jha, C.
Kling, and J. Parcel Center for Agricultural and
Rural Development Iowa State University
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Interim and preliminary results from project

• Funded by Iowa Farm Bureau Federation, Iowa Corn
  Growers Association, the Iowa Soybean
  Association, and the Leopold Center for
  Sustainable Agriculture
• Thanks to IDALS and NRCS for providing key
  cost-share data (more information on poster)
• Iowa Department of Natural Resources, previous
  study provided starting point

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Key Topics

• Briefly summarize DNR work
• Goals of current project
• Project progress
• Information Sources
• Usage of Practices and Statewide Acreage
• Costs of Practices
• Hydrologic Modeling and Water Quality
• Challenges and Gaps

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1. CARD/DNR Study

• DNR goals
• 1. Provide estimate of Iowas needs for
  non-point source pollution water quality
  control
• 2. Inform the debate in Iowa concerning water
  quality
• Study
• 1. Summarize baseline water quality and land use
• 2. Identify set of conservation practices in each
  watershed
• 3. Predict water quality (sediment and nutrients)
  under this set of practices
• 4. Compute cost of those practices (provides
  needs answer)

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2. Current Study

• Goals
• 1. What conservation practices are currently in
  place in Iowa, what is their coverage, and what
  is the cost of these practices?
• 2. What are (and have been) the effects of this
  investment on water quality?
• 3. What would it take to improve water quality to
  obtain specific standards?
• What practices?

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Land Retirement (CRP)
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Terraces
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Contour farming
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Grassed waterways
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Conservation tillage (Mulch till gt30 residue,
no-till gt60)
Reduced tillage (conservation ? 30 residue and
no till ? 60)
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Project progressInformation Sources
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Conservation Programs Used
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Surveys Used
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Project progressUsage of Practices and
Statewide Acreage
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No-Till Installed(only some counties pay
incentive)
IFIP
EQIP
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No-Till Usage for 2004
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Grassed Waterways Installed

• IFIP

• EQIP

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Acres of Grassed Waterways
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Terraces Installed
IFIP
EQIP
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Acres of Terraces
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Acres of Contour Farming
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Acres Enrolled in CRP in 2004
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Project progressCosts of Practices
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Average Cost Per Acre for No-Till
Note No-Till under EQIP includes no-till
strip till

• IFIP

EQIP
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Costs for Grassed Waterways
EQIP

• IFIP

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Estimates of Average Cost for Grassed Waterways

• The average cost of a waterway tends to be very
  variable due to the unique conditions of each
  waterway

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Costs for Terraces

• IFIP

EQIP
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Estimates of Average Cost for Terraces

• The average cost of terraces tend to increase
  across Iowa from east to west
• The average cost of terraces varies depending on
  the type

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Costs for Contour Farming

• IFIP

EQIP
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Average Cost CRP in 2004
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Total Costs of the Practices
872,273,033
413,388,854

• The first two practices are structural
  practices.
• Divide the installation costs over the
  lifespan of the practices (terrace 25yrs, GW 10
  yrs), then the sum of annual payment is
  41,292,852.
• The cost numbers for the rest of the practices
  are annual payments.
• Then the total annual costs would be
• 41,292,852 413,388,854 454,681,706

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Project progressHydrologic Model and Water
Quality
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SWAT Soil and Water Assessment Tool

• Outcome of more than 30-yrs of model development
  experience of USDA-ARS
• Watershed based water quality model
• It was developed to predict the impact of land
  management practices on water, sediment and
  agricultural chemical yields
• Simulates hydrology, sediment, nutrients, and
  pesticides
• Required input data on topography, land use,
  soil, management, and climate

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Watersheds in Iowa
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SWAT Modeling of Iowa Watersheds

• Latest version SWAT2005 was used
• Applied to all 13 watersheds separately
• Calibrated and validated for streamflow on
  annual, monthly and daily basis at watershed
  outlets
• Simulation was conducted for 20 years over the
  period of 1986 to 2005.

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Watershed Characteristics (Source NRI)
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Conservation Practices (Source NRI CTIC)
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Des Moines River Watershed
Example Calibration
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Des Moines River Watershed
Example Calibration
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Des Moines River Watershed
Example Calibration
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Simulated Baseline Results
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Scenario Remove All Conservation Practices
Improvement due to Conservation Practices
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Sediment Yield Reduction
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Nitrate Load Reduction
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Total N Reduction
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Total P Reduction
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Challenges and Gaps

• Data gaps
• Intermittent data collection and lack of central
  data source makes cost data difficult to
  acquire/interpret
• Inconsistent estimates of coverage of
  conservation practices across data sources and
  incomplete data on some practices
• Limited monitoring data makes water quality
  calibration challenging
• Modeling gaps
• Omission of (constructed) wetlands and riparian
  buffers problematic
• Opportunity cost of farmers time, risk attitudes
  makes computation of full costs problematic
• Modeling scale (NRI points will miss some
  heterogeneity)
• Questions
• What water quality gains can be achieved by
  additional placement of practices?
• What targeting criteria to use, i.e., which
  practices to use in which watersheds?
• What are the costs of conservation? How much is
  the cost saving of targeting?
• What would the distributional consequences of
  targeting be?