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4-in-1 crop nutrient management provides multi-crop flexibility and performance

An agronomist's look at fertilizer innovations.

January 23, 2023  Sponsored by ICL Growing Solutions

Jason Haegele leads ICL's research collaborations with universities and third-party research contractors in North America to demonstrate the efficacy of ICL products on a wide range of row crops and specialty crops. He is a graduate of the University of Illinois and Iowa State University. He has a broad range of experience in applied research and field sales support for plant nutrition, adjuvant, crop protection and biological products. Courtesy of ICL

What do farmers and agronomists look for when selecting fertilizers to manage their crops? For most, the cost is certainly a consideration in these volatile markets, but other factors like local availability, convenience, proven agronomic performance and environmental impact are also important. With greater recognition of the economic and environmental challenges of fertilizer use, the emphasis continues to be placed on the 4R framework for nutrient stewardship. Considering the right source, right rate, right time and right place, farmers and their agronomists optimize yield and profitability while also taking the right steps for environmental stewardship. Maybe this is why agronomists get excited when we find simple solutions that can solve more than one industry challenge.

Nutrient stewardship

4R nutrient stewardship is often associated with nutrients like nitrogen and phosphorus, but how does the 4R approach apply to potassium (K) and the secondary macronutrients – calcium (Ca), sulfur (S) and magnesium (Mg)? The fact is, while we might apply them in smaller quantities, secondary macronutrients play an essential role in maximizing crop yield and quality. With increasing demands placed on growers, finding multi-purpose, multi-nutrient products that can simplify processes and reduce costs without sacrificing the environment is key.


So, is there a fertilizer source that allows placing greater amounts of seed-safe potassium close to sensitive crops like canola? How about one that provides sustained timing of nutrient release for quickly lost nutrients like sulfur? Or more readily available calcium than familiar sources like gypsum? Finally, does this fertilizer allow for flexibility in application rate to suit the diversity of western Canadian cropping systems? Surprisingly, the answer to all these questions is yes. Polysulphate, known by its mineral name polyhalite, is a perfect example. It provides a convenient 4-in-1 low salt index source of low-chloride K, Ca, S, and Mg with a sustained release nutrient profile. It applies to diverse crops, including small grains, pulses, potatoes, forages and specialty crops, and as a natural mineral, it is just as nature intended.

What is Polysulphate®?

Polysulphate® is a naturally occurring mineral fertilizer mined exclusively by ICL. Deposited in the earth 260 million years ago, each Polysulphate granule contains sulfur, potassium, calcium and magnesium – four of the six essential macro-nutrients required for optimal plant growth. Today, ICL mines Polysulphate from one location in the world, approximately 1,100 to 1,400 metres deep underneath the North Sea along the coast of the United Kingdom.

Since the sulfur in Polysulphate is in sulfate form, it provides immediate plant availability once released from the granule. But what makes Polysulphate unique compared to other sulfate-S fertilizers is that the sulfur is gradually released throughout the entire season. This season-long release ensures that excess, leaching susceptible sulfate is not present in the soil while also ensuring sulfur is released precisely when the crop needs it.

As a multi-nutrient, it also brings with it other benefits. Polysulphate contains approximately one-fourth of the potassium analysis of potash (potassium chloride), but the potassium in Polysulphate is very low chloride (about 2.4 per cent) compared to the 45-48 per cent chloride concentration of potash. Coupled with a low salt index, this low chloride analysis of Polysulphate makes it ideal for sensitive seeds like canola.

While sulfur and potassium are essential for all crops, calcium becomes of greater importance for fruit and vegetable crops like potatoes (when quality is equally important to overall yield). Often, fertilizer sources like gypsum provide calcium, but gypsum is very slow in its release and can bring handling challenges. In contrast to gypsum, the calcium contained within Polysulphate begins to release sooner in the season, coinciding with the time that potatoes need calcium most to minimize internal defects and improve storage stability.

The bottom line

The bottom line is that most of us are looking for cost-effective ways to grow more with less. By integrating multi-nutrient products that align crop demand, superior seed safety and excellent blending characteristics, we take a step closer to achieving that goal. In Canada, Polysulphate is available both crushed and screened as a granular product or a highly uniform prilled product especially suited to applying with air seeders. Either way, when looking at new products, proven performance, agronomic flexibility and 4R suitability are driving nutrient management decisions today.

When considering your 2023 fertilizer program, think about dual-purpose, multi-nutrient inputs that can help you take your nutrient management program to the next level. Innovative solutions are available to meet your needs, and your local ICL agronomist can help.

ICL Growing Solutions – the world’s leading fertilizer manufacturer. We provide growers with a wide range of high-performance agricultural innovations, including high-end specialty mineral products for every need. Our products provide farmers with critical nutrients required to increase yields sustainably and improve the health and quality of crops. Learn more about ICL’s cutting-edge solutions at


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