February 2020

Aspire® Potato Topdress Study


Evaluate potato yield response to Aspire® with Boron (0-0-58-0.5B) compared to MOP (0-0-60) when applied across multiple application timings.


  • Potassium (K) and boron (B) are key components of a potato nutrition program.

  • Boron is crucial for promoting tuber yield, internal quality, and storability.

  • Ensuring K and B availability through bulking is difficult on coarse, well-drained sandy soils and often necessitates in-season nutrient applications.

  • Research has shown that K fertilizers containing micronutrients in a single granule provide improved nutrient distribution.

  • Aspire® provides both early- and late-season boron nutrition for a flexible application window to better accommodate various application methods
    and timings.

Trial Details

Locations and Crop Management:

CROP: Potato (Solanum tuberosum)

YEARS: 2018-2019

LOCATIONS: 5 trials (Michigan and Wisconsin)

DATA SOURCE: Field studies conducted by independent third-party researchers.

EXPERIMENTAL DESIGN: Small-plot RCBD with 4 replications.

Cultivar: Chipping Potato (MI-Lamoka; WI-Dark Red Norland)


  • Nitrogen and phosphorus was applied to the entire trial

  • Source, Timing and Rate:

- Preplant: Immediately prior to planting

- Topdress: 2-3 weeks following planting

  1. MOP (Preplant): 300 lbs K₂O/ac

  2. MOP (Preplant): 180 lbs K₂O/ac | MOP (Topdress): 120 lbs K₂O/ac

  3. Aspire (Preplant): 300 lbs K₂O/ac + 2.5 lbs B/ac

  4. Aspire (Preplant): 180 lbs K₂O/ac + 1.5 lbs B/ac | Aspire (Topdress): 120 lbs K₂O/ac + 1.0 lbs B/ac

Potato Topdress Study Results


  • The trials were responsive to the need for season-long K and B availability.

  • Aspire® increased yield over MOP by 17 cwt/ac in the “Preplant” treatment and 19 cwt/ac in the “Preplant”+”Topdress” treatment.

  • Split applying MOP gave a 7 cwt/ac increase over MOP (Preplant), while split applications of Aspire® resulted in a 9 cwt/ac increase compared to Aspire® (Preplant).

  • Collectively, these findings suggest that a total improvement of 26 cwt/ac is possible with better nutrient source selection and split application practices.

©2020 The Mosaic Company. All rights reserved. AgriFacts, MicroEssentials, SZ, Fusion, Aspire and NutriForm are registered trademarks of The Mosaic Company.

Individual results may vary, and performance may vary from location to location and from year to year. This result may not be an indicator of results you may obtain as local growing, soil and weather conditions may vary. Growers should evaluate data from multiple locations and years whenever possible.

WARNING: Contains boron. Use of boron may result in crop injury. DO NOT place this product in direct contact with the seed.