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Home > Protecting Our Lands & Waters > Clean Water Fund > On-Farm Projects > Nutrient Management Initiative > Field Trials

NMI Field Trial Evaluations

Example of layout for NMI field trialsField trial evaluations include: nitrogen rate, timing, stabilizer, sourcerate after manure and advanced rate trials. Examples and criteria for each are listed below.

Farmers and crop advisers can suggest other field trials for management practices they feel could provide benefits for both improving farm performance and reducing nitrogen losses.

 Criteria for all trials:

  • Field length strips preferred, minimum of 30 feet wide by 600 feet in length
  • Corn grown and harvested for grain only
  • Keep all other factors consistent across field trial area (variety, other nutrients, rates, soils, field history, drainage, topography, equipment)
  • Crop adviser submits information to verify accuracy (If a farmer does not have a crop adviser, please contact closest NMI representative for assistance.)

Nitrogen rate trials


Preplant: Urea 150 lb N/acre vs 120 lb N/acre
Side dress: 28% UAN 20 gal (60 lb N/acre) vs (30 lb N/acre)
Dealer Nitrogen Programs comparisons (Greenseeker, VRT, Adapt N, Climate Corp, 360 Yield Center)

Nitrogen rate additional criteria

  • For best results, only use N sources without additional nutrients in the formulation when applying the different rates. Applications of starter, AMS, MAP, DAP, or blends of products should not be used for the nitrogen rate difference.
  • 30 lb N/acre minimum rate separation
  • No manure or alfalfa history within the past two years for this trial

Nitrogen timing trials


Fall vs Spring
All Preplant vs Side dress/Split

Nitrogen timing additional criteria

  • For best results, use the same nitrogen source applied at a different time
  • Use the same equipment for both treatments applied at a different time only
  • Manure applications are eligible. Provide manure information on Crop Management Form

Nitrogen stabilizer trials


N-Serve, Instinct, ESN, Agrotain

Nitrogen stabilizer additional criteria

  • Use the same nitrogen rate, source, timing, and placement for both treatments
  • Comparisons between different stabilizer products, or blends of products, can be used as long as all other inputs are consistent
  • Read and follow the stabilizer label for the recommended application rates
  • Manure applications with a stabilizer are eligible. Provide manure information on Crop Management Form. Please contact NMI Representative first

Nitrogen source trials


UAN vs Anhydrous Ammonia

Nitrogen source additional criteria

  • Use the same nitrogen rate, source, timing, or stabilizer applied with a different nitrogen source only
  • For best results, using the same nitrogen placement is preferred
  • Contact NMI Representative with other suggestions

Nitrogen rate after manure trials


Preplant: Urea 60 lb N/acre vs 30 lb N/acre
Side dress: 28% UAN 20 gal (60 lb N/acre) vs 10 gal (30 lb N/acre)
Evaluate first and/or second year manure nitrogen credits

Nitrogen rate after manure additional criteria

  • Use the same commercial nitrogen source applied at a different rate only following manure (30 lb N/acre minimum rate separation)
  • Use the same manure source, rate and application method over the field area
  • Account for manure source, analysis, application rate, and appropriate credits in the Crop Management Form
  • Current manure test for nitrogen should meet current local and state permitted standards 

Advanced rate trials

These sites are newer to the program. They are designed to answer questions that farmers have about nutrient management and to inform the University of Minnesota’s current nitrogen fertilizer recommendations.

Additional compensation is available for farmers and crop advisers participating in advanced rate trials. Participating farmers are compensated $1,000 and crop advisers are compensated $500 for each field trial.

Advanced trial additional criteria

  • Must have corn-corn or corn-soybean rotation history
  • No manure or alfalfa history in the last 5 years
  • Install a minimum of 1 test strip at least 30 ft wide, and 1/2 mile long or multiple test strips equivalent to a 1/2 mile (2640 ft)
  • Nitrogen rate test strips contain 5-6 unique N rates and each N rate replicated 3 times
  • 40-50 lb difference between N rates
  • Must include zero rate check strip (check strip can only include N contributions from DAP or MAP applications)
  • Soil types, topography, drainage, and field history should be consistent across the trial area
  • Variable rate technology (VRT) and yield monitors to aid in field trial design, installation, and harvest