K-Mag^® Onion Blend Study – AgriFacts

OVERVIEW

• Phosphorus (P), along with potassium (K), magnesium (Mg) and sulfur (S) are macronutrients needed for a balanced crop nutrition program in onions.
• Magnesium is critical for photosynthesis, increased dry matter, heat-stress tolerance, disease resistance, and crop quality.
• Ensuring K, Mg, and S availability through bulb development can be difficult on coarse, well-drained sandy soils.
• 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 application rate.

TRIAL DETAILS

Crop: Onion (Allium cepa)

Years: 2019-2020

Locations: 4 trials across the following states – ID, WA

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

Experimental Design: Small-plot RCBD with 4 replications.

Cropping Conditions: All trials conformed to local cropping practices.

TREATMENTS:

Treatment (Trmnt) / Rates / Timing:

1. N Rate: Applied according to local recommendations
2. P Rate: 100 lbs P₂O₅/ac applied as MAP
3. K Rate: 120 lbs K₂O/ac applied as either MOP or a blend of MOP (90 lbs K₂O/ac) + K-Mag (30 lbs K₂O/ac)
4. Application Timing: Preplant

Application Method: Broadcast Incorporated

RESULTS

SUMMARY

• Addition of MOP increased onion yield 6 cwt/ac compared to MAP only.
• Replacing a small amount of MOP with K-Mag (30 lbs K₂O) increased onion yield by 26 cwt/ac over MAP + MOP. These results demonstrate the value of K, Mg, and S for a balanced crop nutrition program in onions.
• Access additional yield data, technical information, and resources at KMag.com/Performance.