February 2021

Performance Acre - Onion Balanced Crop Nutrition


Evaluate onion marketable yield response to MAP (11-52-0), MAP + MOP (0-0-60), MicroEssentials® SZ® (12-40-0-10S-1Zn) + MOP, and a combination of MicroEssentials SZ + Aspire® (0-0-58-0.5B).


  • Phosphorus (P) and potassium (K), along with sulfur (S), zinc (Zn) and boron (B), are essential nutrients needed for a balanced crop nutrition program in onions.

  • Ensuring K, S, and B availability through bulb development can be difficult on coarse, well-drained sandy soils.

  • MicroEssentials SZ contains N, P, S, and Zn combined into one nutritionally balanced granule, providing uniform distribution, increased nutrient uptake, and season-long S availability.

  • Aspire combines potash along with two forms of B (fast and slow release) in every granule for uniform distribution, season-long B availability, and a flexible application window.


Crop: Onion (Allium cepa)

Years: 2019-2020

Locations: 4 trials in Idaho and Washington

Data Source: Field studies conducted by independent, third-party researchers.

Experimental Design: Small-plot RCBD with 4 replications.

Cropping Conditions: All trials conformed to local cropping practices.


Treatment (Trmnt) / Rates / Timing:

  1. N Rate: Applied according to local recommendations

  2. P Rate: 100 lbs P₂O₅/ac applied as MAP or MicroEssentials SZ

  3. K Rate: 120 lbs K₂O/ac applied as either MOP or Aspire

  4. Application Timing: Preplant

Application Method: Broadcast Incorporated


Performance Acre™ - Onion Balanced Crop Nutrition - Results


  • Addition of MOP increased onion yield 6 cwt/ac compared to MAP only.

  • MicroEssentials SZ + MOP increased yield by 62 cwt/ac over MAP only and 56 cwt/ac over MAP + MOP.

  • Replacing MOP with Aspire increased yield 88 cwt/ac over MAP + MOP and 32 cwt/ac over MicroEssentials SZ + MOP.

  • Higher yields achieved using MicroEssentials SZ + Aspire demonstrate the value of combining P, K, S, Zn, and B for a balanced crop nutrition program in onions.

©2021 The Mosaic Company. All rights reserved. Performance Acre is a trademark and AgriFacts, Aspire, MES, SZ and MicroEssentials 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. For more information, go to cropnutrition.com.