Whatsapp 
X 
Mail 
Copy link 9 Reasons to Choose Polysulphate® for Fall-Applied Sulfur in Canola
Not all sulfur sources are created equal. Compare traditional sulfur sources with polyhalite and learn why more growers are making the switch to Polysulphate.
On this page:
Polysulphate® is a natural polyhalite fertilizer that supplies sulfur, potassium, magnesium, and calcium in plant-available form, making it ideal for fall-applied nutrition in canola. It provides reliable sulfur availability, reduces leaching and oxidation losses, supports strong emergence, and improves nutrient efficiency, helping growers strengthen early growth, optimize yields, and enhance long-term soil health in Western Canada.
Sulfur is one of the most important nutrients for canola production in Western Canada.
Canola requires 0.55 to 0.8 pounds of sulfur (S) per bushel of yield, and around 55% of uptake is removed with the seed (Canola Council of Canada, 2016). With more frequent canola rotations, higher yields, and sulfur’s mobility in soil, reserves are being steadily depleted. Soil fertility expert Dr. Ross McKenzie estimates that at least 40% of Prairie soils are sulfur-deficient.
While fall can be an ideal time to ensure sulfur is in place, not all sulfur sources behave the same. Elemental sulfur has long been promoted for fall application, but its effectiveness depends on microbial oxidation — a process that can be slow and unpredictable in Prairie soils.
Polysulphate® is different.
It behaves differently than both elemental sulfur and highly soluble sulphate products. As a natural, gradual-release mineral, Polysulphate (natural mineral polyhalite) provides sulfur in the plant-available sulphate form, along with potassium, magnesium, and calcium — nutrients that support canola growth and soil health. Here are nine reasons why Polysulphate should be in your bins and on your fields this fall.
1. Dependable Sulfur Supply
Unlike elemental sulfur, Polysulphate delivers sulfur in the sulphate form, ready for plant uptake, but — Polysulphate has a naturally gradual release. Research shows that its sulphate is released more steadily than ammonium sulphate or other fully soluble fertilizers. As a natural mineral (polyhalite), it is immediately available and dissolves over weeks and months as soil moisture fluctuates. This means nutrients are supplied not only at emergence but also through flowering and pod fill, aligning with canola’s peak sulfur demand.
2. Reliable Performance in Prairie Conditions
Because it doesn’t rely on microbial oxidation, Polysulphate works consistently regardless of soil temperature, moisture, or microbial activity — a major advantage in Western Canada’s short growing season.
3. Multi-Nutrient Value
Polysulphate contains sulfur already in the sulphate form. In addition to sulfur, Polysulphate provides potassium, magnesium, and calcium. These nutrients support photosynthesis, pod fill, nutrient balance — boosting yield, quality and long-term fertility. Mg and Ca also help improve soil structure and cation balance, especially beneficial where those are limiting.
4. Residual Value Across Seasons
While not a long-term “bank” like elemental S, some nutrients from fall-applied Polysulphate remain available into the following season, especially in cooler, drier Prairie soils where leaching is limited. It’s particularly useful when you’re unable to apply in spring or if environmental conditions make oxidation of elemental S uncertain.
5. Low Salt Protects Seeds and Supports Strong Emergence
Polysulphate has a low salt index and low chloride K, making it gentler on seeds than many other fertilizers. This helps protect seedlings, improve stand count, and set up a strong, uniform crop.
6. Reduces Risk of Deficiency
Elemental sulfur often fails to fully oxidize by spring, leaving canola short when it needs S the most. You can use fall-applied Polysulphate as a building program, but its strength lies in providing a reliable, gradually released sulphate source that carries into the next growing season. Polysulphate ensures a reliable sulfur supply is already in place when the crop needs it most.
7. Flexibility Fits Fall and Spring Programs
Whether applied in fall or spring, Polysulphate performs consistently and effectively. For growers, fall application provides peace of mind that sulfur is available regardless of spring weather challenges.
8. Sustainable and Natural
Polysulphate is simply mined, crushed, and screened — not chemically processed. This gives it a low carbon footprint, aligning with grower and consumer demand for more sustainable solutions. Plus, it’s OMRI-approved.
9. Low Leaching Risk
Compared to highly soluble sulphate fertilizers, Polysulphate’s steady dissolution reduces the risk of leaching, helping nutrients stay available where roots can reach it, while minimizing environmental risks and reducing valuable nutrient loss.
Comparing Fall-Applied Sulphur for Canola in Western Canada
| Factor | Elemental Sulphur (S⁰) | Polysulphate® |
|---|---|---|
| Nutrient Form | Insoluble elemental S; must oxidize to sulphate before plants can use it | Naturally occurring mineral supplying sulphur directly in the sulphate form (plant-available) |
| Availability to Crop | Slow and unpredictable — conversion depends on microbial activity, soil temperature, and moisture | Plant available sulphate plus gradual release over weeks, ensuring reliable supply through spring and summer |
| Consistency & Reliability | Variable — risk of insufficient sulphur for canola’s high early-season demand | Predictable performance regardless of conditions |
| Release Pattern | Very slow — months to years for full oxidation | Gradual dissolution with both immediate availability and sustained supply |
| Multi-Nutrient Value | Provides sulphur only | Provides sulphur + potassium, magnesium, and calcium |
| Seed Safety | Can increase salt risk if applied too close to seed row | Low salt index protects seeds and supports emergence and stand count |
| Leaching Risk | Low until oxidized, but also delays availability | Low — gradual release better matches crop uptake |
| Best Fit in Fall Programs | Long-term “banking,” but unpredictable for immediate needs | Reliable sulphur supply plus added nutrients for immediate and season-long canola requirements |
Why This Matters for Canola Growers
Canola growers across the Prairies and beyond face short growing seasons, cool soils, and widespread sulfur deficiency. While fall-applied elemental sulfur can contribute to long-term soil reserves, it’s often too slow to meet canola’s early-season needs. Elemental sulfur (S⁰) must be converted by soil microbes into sulphate (SO₄²⁻) — a process that can take months or even years, especially under Prairie conditions.
Polysulphate® offers a more reliable solution. It supplies sulfur in the plant-available sulphate form, with a gradual release that aligns with canola’s growth stages. Its low salt index protects seedlings, and its multi-nutrient package supports yield, oil content, and soil health.
For growers looking to safeguard early-season sulfur availability and improve overall crop performance, Polysulphate® is a smart, sustainable choice for fall-applied fertility.
Sources:
• Canola Council of Canada. Need to know: Sulfur in canola. April 12, 2016.
• Canola Council of Canada. Fall for elemental sulfur. October 2, 2013.
