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Home > Protecting Our Lands & Waters > Best Management Practices > Field Scale Drainage Water Quality Demonstrations > Highway 90 Field-Scale BMP and Water Quality Demonstration

Highway 90 Field-Scale BMP and Water Quality Demonstration

Highway 90 Demonstration Site aerial viewA water quality demonstration in cooperation with Minnesota—Corn Growers, Soybean Growers, Crop Production Retailers, CertifiedCrop Advisers, Independent Crop Consultants, University of Minnesota, Minnesota State University-Water Resource Center, Blue Earth River Basin Alliance, Minnesota Pollution Control Agency and the Minnesota Department of Agriculture.


Located within the LeSueur River watershed, the Hwy 90 demonstration field is located in close proximity to Minnesota State Highway 22 and Blue Earth County Road 90, south of Mankato, Minnesota. This thirty-two acre water quality demonstration site provides critical information on the characteristics of agricultural drainage from field-scale conditions in south-central Minnesota. This information will assist in evaluating the water quality impacts associated with the University of Minnesota fertilizer recommendations, newly established pesticide Best Management Practices (BMP’s) and nutrient BMPs under field-scale conditions. Hwy 90 demonstration site will also compliment long-term work already completed at the Red Top Demonstration Site in Nicollet County.

The Minnesota Department of Agriculture with support from agriculture industry submitted a Federal Section 319 grant proposal to the Minnesota Pollution Control Agency during the fall of 2003. This proposal was accepted and contract signed in October of 2005. Site selection process involved interviews with numerous farmers and viewing of numerous pattern tiled drainage systems. The Hwy 90 site was selected because of similar soil series, accessibility, and representative drainage management practices that are commonly found in southern Minnesota. Tile modifications and four additional tile lines were added at the site in December of 2005. Monitoring equipment installation and base line information was collected during the summer of 2006. The site is intended to be a long-term demonstration site evaluating best management practices (BMP’s), water quality changes, and new technologies.

Highway 90 Demonstration Site soils mapFIELD Characteristics

  • Soil Type: Silty Clay Loams
  • Marna and Minnetonka Soil Series
  • < 2% Slope-elevation field variation less than 6’
  • Organic Matter: 3.5-6%
  • Phosphorous soil test: medium-high
  • Potassium soil test: high
  • Tillage: Moldboard plow and spring cultivation
  • Tile system: Subsurface pattern tiled, no surface intakes

Project Description: Hwy 90 site features four individual simulated watersheds (N1, N2, S1, and S2) from the field. These watersheds range in sizes from 5.3-9.4 acres with each having its own subsurface tile drainage system.



Figure 1. Diagram of watersheds at Hwy 90 demonstration sites showing the tile lines layout.

Northern Watersheds (N1 & N2)

  • Age: 15 years
  • Main lines: 6 inch plastic tile
  • Laterals: 5”
  • Average Spacing: 80 feet
  • Average Depth: 3.5-4 feet
  • Watershed: 15.5 Acres
Highway 90 demonstration site tile lines

Southern Watersheds (S1 & S2)

  • Age: 4 -24 years
  • Main Lines: 6 inch plastic tile
  • Laterals: 6”@ 100’ concrete split with 4” plastic
  • Average Spacing: 50 feet
  • Average Depth: 3.5-4 feet
  • Watershed: 16.4 acres
  • Surface inlets: None

Objectives & Methods

To evaluate nutrient and pesticide management strategies and practices to ultimately reduce non-point source pollution while protecting farm profitability.

  • Establish a field-scale environment similar to regional conditions and agro-ecosystems.
  • Comparison of 50’ and 80’ drainage spacing evaluating flow characteristics, nutrient and pesticide losses and other environmental influences.
  • Evaluate side by side comparison of currently practiced nutrient application and timing strategies in south-central Minnesota to U of M recommended nutrient guidelines and Best Management Practices (BMP’s).
  • Evaluate pesticide BMP’s and evaluate pesticide losses under normal field scale management.
  • Crop management variables minimized to eliminate inaccurate results. Crop management strategies to be determined by consultation with established advisory board, local crop consultants, and retailers.
  • Economic analysis of following strategies will be evaluated through Farm Business Management program.
  • Promote existing proven management tools and new emerging technologies.
  • Evaluate soil test changes & economic results by using variable rate fertilizer applications.

Figure 2. Watersheds S-2 and N-1 established to evaluate U of M recommendations and spring application of nitrogen. Watersheds S-1 and N-2 are evaluating a rapid phosphorous nutrient build-up program using variable rate technology and fall applied anhydrous ammonia. Yield results, economic outcomes, and water quantity and quality will be evaluated from each of these practices.

 Highway 90 demonstration site application rates

Figure 4. Yearly monitoring results and management history. 2006 establishment year.

 Highway 90 demonstration site water monitoring results and cropping history

MDA Contact

Ryan Lemickson
Fertilizer Field Unit

Pesticide & Fertilizer Management Division