Recent research by the University of Manitoba gives strong indication that canola farmers should reconsider application rates of phosphorus (P) and sulfur (S) to unlock higher yields.

For years, canola farmers have based P and S application rates on seed safety, but research is showing that today’s canola hybrids have a higher requirement for P and S throughout the growing season. Canola requires approximately 1.4 pounds of P2O5 per bushel of canola and 0.6 pounds of S per bushel to reach maximum yields. Of the nutrients taken up by the plant, canola’s grain removal of P and S is 0.8 pounds per bushel and 0.3 pounds per bushel, respectively. At these rates, a 45 bu/ac crop of canola will remove 36 pounds of P2O5 and 13.5 pounds of S from the soil.

This is higher than the typical seed-placed rates, and continued under-application of P and S will limit yield potential and deplete soil reserves.

"With any crop, it’s important to have a keen understanding of how much of a nutrient is being removed from the soil so that balanced crop nutrition can be achieved," says Curt Woolfolk, Sr. Agronomist for The Mosaic Company. "This research shows that yields have outpaced nutrient replenishment strategies in canola, and growers may want to look more closely at application rates."

During this study, the University of Manitoba applied phosphorus and sulfur at two different rates and found that when P fertilizer rates were increased (with low S treatments), there was a 2.4-bushel-per-acre yield increase. The increased yield result suggests that current seed-safe P rates may not be meeting crop requirements.

Included in the study was MicroEssentials S15. The trial found that MicroEssentials S15 provides both the P and S a canola crop requires, and when applied at higher rates, proved to be less damaging to plant stands than a comparable blend of MAP and AS. A key feature of MicroEssentials is the combination of both sulfate S and elemental S for season-long availability.

For more information on the MicroEssentials product portfolio or to find a MicroEssentials retailer near you, visit MicroEssentials.com and for more on recent soil fertility research findings, visit cropnutrition.com/agrisight.