Nitrogen Rate Validation

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Nitrogen Rate Validation

• St. Peter Wellhead Protection Project

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St. Peter Wellhead Protection

• History and description of the project area
• Water quality issues
• Early initiatives
• Challenges
• Nitrogen rate validation project and results
• Lessons learned
• Future activities

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Location
St. Peter
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St. Peter Drinking Water

• City provides 350 million gallons of drinking
  water/year to the 10,000 citizens of St. Peter
• 3 separate aquifers supply water to 7 wells that
  vary in depth from 130-670 feet deep
• These wells feed two water filtration plants that
  treat the water and then pump it to 2.5 million
  gallon capacity storage locations

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Project Background

• Project took place because of water quality
  concerns by the city of St Peter
• Throughout the 1980s Nitrate-nitrogen
  concentrations had been rising slowly but
  steadily in the citys Jordan Aquifer wells
• City had to take a Reactive and Proactive Response

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Project Background

• Water Quality Issues
• Increasing nitrate trend in Jordan aquifer,
  nearing Federal Drinking Water Standard (10 ppm)
• Response Strategy
• Reactive
• Drilled new, deeper wells, use blending process
• Consider expensive nitrate filtering systems
• Proactive
• Development of a Wellhead Protection Plan

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St. Peter Wellhead Protection Area

• Characterized by
• 25-year time of travel
• Diverse soil textures
• Row crop dominated land use
• No livestock production
• 4500-acre Drinking Water Supply Management Area
  (DWSMA)

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Sandy Soils

• About 15 of the wellhead zone is characterized
  by glacial outwash parent material (Sand
  Prairie)
• Rapid permeability
• Excessively drained
• Coarse textured
• Dickinson sandy loam and Plainfield loamy sand
  soil series
• High nitrate probability

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Nitrate Probability
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Soils
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Land Use
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Nitrate Probability
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Nitrate Trends
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Project Background

• Monitoring to assess the extent of the aquifer
  problem started in the late 1980s
• A phase I Clean Water Partnership was organized
  to help fund this initiative. This PCA-funded
  project helped distinguish aquifer-wide problems
  from individual well problems
• Other studies included age-dating using Tritium
  and CFC methods, and groundwater flow modeling

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Project Background

• From 1993 to 1998 the Clean Water Partnership
  (CWP) moved from the study phase to the
  implementation phase
• The CWP provided education about nitrogen BMPs to
  farmers in the wellhead area for the ag
  perspective
• And to city residents for the lawn-care
  perspective

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Minnesotas Nitrogen BMPs
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Project Background

• At the end of the Phase II project a farm
  practice survey was conducted to evaluate the
  effectiveness of the educational campaign.
• The study did find that many producers were
  voluntarily adopting educational materials and
  strategies developed by the UM, however it was
  also also clear that there was still room for
  improvement.

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FArm Nutrient Management Assessment
Program(FANMAP)
UM Recs Actual Inputs
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FANMAP Summary
Corn Acreage Receiving 30 Pounds/A More than
UM Recs

• 30 lb/A or more
• Within
• 30 lb/A

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Potential Reduction of Annual N Inputs Based on
UM Recs

• St. Peter --- 135,000 lbs
• SWP Area
• Or
• Potential Reduction of 3,000-4,000 Lbs of N per
  farm!

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1997 Farm Practice Survey Findings

• Over 96 of the corn acres were in a corn/soybean
  rotation.
• This is a clean system due to the lack of
  livestock in the management area
• 96 of the corn acres fell into the excessive
  category (gt30 lb/A above UM Recommendation)

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Continued.1997 Farm Practice Survey Findings

• Factoring in all appropriate credits from
  fertilizer, legumes and manures, on average there
  was an over application rate of 53 lb/N/acre
• Reducing the average amount of N applied and
  accounting for soybean credits could save farmers
  approximately 10/acre
• Lack of confidence in UM Recommendations and/or
  lack of soybean crediting accounts for most of
  the over-application

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Challenges

• Gap continues to exist between awareness of
  nitrogen best management practices (BMPs) and
  adoption
• Producers and fertilizer dealers feel University
  of MN Extension Nitrogen Recommendations are not
  valid on their farm, soils, landscape, etc
• Producers not willing to reduce nitrogen rates
  unless locally derived, statistically valid
  information is made available that proves
  otherwise

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St. Peter Source Water Protection AreaThird
Phase

• In the late 1990s, nitrogen management
  initiatives revived
• This third phase incorporated crop consultants
  and agri-business cooperatives

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Third Phase

• Establish localized research/demonstration
  activity through on farm-demonstrations
• Enroll sensitive areas into conservation programs
• Revaluate effectiveness of educational outreach

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Potential N Leaching LossesMN River Basin
Acreages
MDA and UM
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Typical Nitrogen Losses Under Different
Vegetation and Management
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Nitrogen Rate Validation Project

• With the help of new technologies (GPS and GIS)
  we can take statically valid research to their
  fields
• Compensate for potential yield losses
• Hire an agronomist to assist with setting up the
  on-farm demonstrations and consulting services
• Continue to educate fertilizer dealers/consultants
  /Coops

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Nitrogen Rate Validation Project

• Initial funding via EQIP Educational Grant
• MN River Initiative Funding 1999-2000
• 319 Clean Water Act Funding 2000-2002

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St Peter Nitrogen Rate Validation Project

• Key Purpose
• To determine economically optimum N rates at the
  field scale level for corn following soybeans in
  effort to accelerate the voluntary adoption of UM
  Recommendations (specifically N Rates) in the St
  Peter Wellhead Protection Zone.

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Fundamental Nitrogen Relationships
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St Peter Nitrogen Rate Validation Project

• Procedures
• Demo Years 2000, 2001, 2002
• Fields 2000-8 funded 5 used 2001-5 funded 4
  used, 2002-3 funded
• Locations St. Peter Wellhead Protection Zone
• Replications 3
• N Rate (lb/A) 0, 60, 90, 120, 150 applied by
  dealer or farmer using BMPs
• Strip Width 30 to 60 feet
• Strip Length 600 to 1200 feet long
• Harvest combine with GPS enabled yield monitor

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St Peter Nitrogen Rate Validation Project

• Procedures
• Each site was selected by a consultant with the
  farmer
• soybean was the previous crop
• no manure applied for at least 5 years
• adequate drainage
• crop planted, managed, and harvested by the farmer

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On Farm Nitrogen Rate Demonstrations

• 40-acre field-corn-soybean rotation with soybeans
  previous year (no manure in past 5 years years)
• Field is geo-referenced
• Nitrogen is applied in random strips at 0, 60
  ,90, 120, and 150 lb./N/acre and replicated 3
  times in the field
• Field is combined using GPS equipped yield
  monitor
• Weigh wagon yield from each strip to validate
  yield monitor

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Incentives to Producers

• Custom combining
• Payment for custom application of N strips
• GPS mapping
• Profit differential for yield reduction
• Economic Optimal Nitrogen Rate (EONR) analysis
• Crop consultant

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Data Layers
80 acre field
Soil Survey Information
N-Rates Strips
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On-Farm Demonstration Design
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Geo-Referenced Yield Maps
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St. Peter Nitrogen Fertilizer Rate Validation
Project-2000
Yield (Bu/acre)
N Fertilizer Rate on Corn Following 1999 Soybeans
(Lb/A)
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St. Peter Nitrogen Fertilizer Rate Validation
Project-2001
Yield (Bu/acre)
N Fertilizer Rate on Corn Following 2000 Soybeans
(Lb/A)
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St. Peter Nitrogen Fertilizer Rate Validation
Project2000 and 2001
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Basic Economical Analysis
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Nitrogen Response Curves by Farm
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Corn Yield by Soil Type
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Economical Optimum Nitrogen Rate (EONR) by Farm
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Economical Optimum Nitrogen RateAssuming N Price
Is Constant (0.2 / Lb N )
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On-farm Demo Results

• Optimum rate of nitrogen varied by soil type, and
  farm. Again it emphasizes yield is a result of
  interaction between many factors such as soils,
  drainage, hybrid, fertility, or
  disease/weed/insect pressures.
• Applications of 90 to 120 pounds of nitrogen per
  acre maximized both yields and profits for
  demonstration years 2000 and 2001.

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On-farm Demonstration Results

• Insurance nitrogen does not guarantee higher
  yields or higher profits. Demo results indicate
  that current wellhead fertilizer rates may be
  reduced from 30 to 60 pounds/acre without a yield
  loss. This could save farmers an average of
  6.00-12.00/acre.
• Field scale nitrogen rate validation within the
  St. Peter Source Water Protection Area
  demonstrated UM Fertilizer Recommendations were
  adequate for optimizing yields and profits.
• Study should be repeated on more fields, over
  more growing seasons to reaffirm the two-year
  demo results.

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Lessons Learned

• Integrate fertilizer companies and dealers/coops
  into the project much sooner since they have the
  greatest influence on management decisions.
• Collaboration with public and private groups are
  key components to long-term successes
• The only constant is change..wellhead protection
  education is a never ending process

Fertilizer Dealers are a Critical Information
Delivery Avenue
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Future Activities

• On farm demos integrated into basin-wide approach
  
• Center for Agricultural Partnerships Midwestern
  Water Quality Project will have over 50 farms
  participating in N-rate demonstrations in the MN
  River valley this year

• Re-survey to measure educational outreach
  effectiveness

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Progress as of 2002
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Nitrogen Rate Validation Project

• St. Peter Wellhead Protection Area

Kevin Kuehner BNC Water Quality Board 322 S MN
Ave. St Peter MN 56082 Kuehnbnc_at_mnic.net 507-934-4
140
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Ultimate Measure of Success

• Success of groundwater improvement projects
  measured over decades, not months
• Revaluation is critical

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St. Peter Wellhead Protection Area

• Characterized by
• 25-year time of travel
• Diverse soil textures
• Row crop dominated land use
• No livestock production
• 4500-acre Drinking Water Supply Management Area
  (DWSMA)

56
Project Background

• From 1993 to 1998 the Clean Water Partnership
  (CWP) moved from the study phase to the
  implementation phase.
• The CWP provided education about
  nitrate-reduction to farmers in wellhead area for
  the ag perspective
• And to city residents for the lawn-care
  perspective

57
FANMAP Summary
Corn Acreage Receiving 30 Pounds/A More than
UM Recs

• 30 lb/A or more
• Within
• 30 lb/A

58
On Farm Nitrogen Rate Demonstrations

• 40-acre field-corn-soybean rotation with soybeans
  previous year (no manure in past 5 years years)
• Field is geo-referenced
• Nitrogen is applied in random strips at 0, 60
  ,90, 120, and 150 lb./N/acre and replicated 3
  times in the field
• Field is combined using GPS equipped yield
  monitor
• Weigh wagon yield from each strip to validate
  yield monitor

59
Lessons Learned

• Integrate fertilizer companies and dealers/coops
  into the project much sooner since they have the
  greatest influence on management decisions.
• Collaboration with public and private groups are
  key components to long-term successes
• The only constant is change..education is a
  never ending process and strategies must adapt to
  the changes

Fertilizer Dealers are a Critical Information
Delivery Avenue