February 2020

K-Mag® Blend Study


Evaluate soybean yield response to MOP (0-0-60) and K-Mag® Premium (0-0-21.5-10.5Mg-21S).


  • Muriate of Potash (MOP) is a common potassium (K) fertilizer used in soybean production.

  • New university research highlights the need for sulfur (S) on soybean due to higher grain yields and lower atmospheric deposition.

  • Soluble magnesium (Mg) has been documented to improve photosynthesis, enzyme activation, and grain yield.

  • K-Mag is a unique 3-in-1 nutrient source that features low chloride, water soluble nutrients, and does not affect soil pH; regardless of rate.

Trial Details

Locations and Crop Management:

CROP: Soybean (Glycine max)

YEARS: 2018-2019

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

EXPERIMENTAL DESIGN: Small-plot RCBD with 4 replications.


All trials conformed to local cropping practices

P Rate: 40 lbs P₂O₅/ac applied as DAP (18-46-0) or MAP (11-52-0)

K Rate: 60 lbs K₂O/ac as either MOP or a blend of MOP (50 lbs K₂O/ac) + K-Mag (10 lbs K₂O/ac)

Application Timing: Preplant

Application Method: Broadcast Incorporated

K-Mag Blend Study Results


  • Replacing a small amount of MOP with K-Mag increased soybean yield by 2.2 bu/ac over MOP when averaged across 22 trials (2018-19).

  • These results demonstrate the value of K, Mg, and S for current soybean genetics and production systems.

  • Access additional yield data, ROI calculators, and resources at K-Mag - Performance.

©2020 The Mosaic Company. All rights reserved. AgriFacts® and K-Mag® 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.