Carbon Footprint of Polysulphate Cut by Over 90%

ICL reaffirms its commitment to sustainable polyhalite production, reducing the carbon footprint of Polysulphate fertilizer.

June 4, 2024
5 mins
  • Polysulphate fertilizer delivers significant reductions in carbon emissions for growers
  • Major environmental and productivity gains alongside food supply chain benefits
  • Renewable energy switch and more efficient working practices among improvements at ICL’s Boulby Mine


ICL has reduced the carbon footprint of its organic mineral polyhalite – sold as Polysulphate multi-nutrient fertilizer by around 90% in the last five years. This reduction is a result of production efficiency improvements and infrastructure upgrades at ICL’s Boulby Mine in North Yorkshire, UK.

Polysulphate is already recognized as a low-carbon fertilizer, but the latest reduction to 0.0029 per kg of CO2 e of product reduces this figure much further and offers even greater opportunities for farmers and the wider supply chain to decarbonize agriculture, says ICL UK Technical Sales Manager Richard Ward. “This reduction demonstrates ICL’s ongoing commitment to playing a key role in a food and farming industry that is increasingly focused on meeting sustainability and carbon targets.”

“Traditional manufactured fertilizers that are providing sulfate in the form of nitrogen sulfur products are coming increasingly under the spotlight as major carbon contributors in the food supply chain. Polysulphate is leading the way in producing food for humans and animal consumption in a more sustainable way.”

A recent paper released in the UK by Prof. David Powlson, an Emeritus scientist at Rothamsted Research, concluded that if all ammonium sulfate imported into the UK was replaced by Polysulphate, one simple switch of product could deliver 20% of the UK’s ammonia emission targets. This equates to a 90% reduction to in-field use.

Global crop trials also conclude that Polysulphate delivers economic gains for farmers by improving crop yield and quality due to its high efficiency. Its nutrients help increase the nitrogen use efficiency by plants from both nitrogen fertilizers and organic sources, whilst its prolonged release characteristics also reduce losses of harmful elements to water and the air.

“With farmers becoming more incentivized to adopt more sustainable farming practices, Polysulphate is ideally positioned as the future direction of the industry. Our goal is to help farmers increase their productivity and profits in a more sustainable way.”

“The benefits of Polysulphate are already being recognized by many growers, agricultural advisers, and the wider food supply chain, with thousands of farmers now using the product, with ICL Boulby setting a new record of one million tons of Polysulphate produced in 2023 for distribution worldwide,” says Richard Ward.

Ongoing improvements

According to ICL UK VP and General Manager Grahame Wallace, the reduction in Polysulphate’s carbon footprint is the result of an ongoing program of energy improvements at ICL’s Boulby Mine. The site’s recent achievement of ISO 50001 accreditation recognizes that it has established a comprehensive structure for energy management with a focus on continual improvement.

Since the last carbon footprint calculation in 2019, ICL has introduced numerous changes including changing to fully renewable electricity in 2023 and removal of the combined heat and power plants (CHP).

ICL has also made considerable strides in reducing diesel use and introduced a range of efficiency improvements across the site and operational processes.

The structured and consistent energy management approach, recognized by the achievement of ISO 50001, has provided us with a platform for reducing our energy consumption and efficiency. Virtually all areas of the business have risen to the challenge of identifying ways to improve ICL’s carbon footprint.

It is, however, very much an ongoing process. The recent carbon footprint evaluation has brought new vigor to the team by highlighting the success of what we have achieved whilst also providing a focus on areas for improvement that we will be targeting in 2024, including the replacement of air compressors across the site to provide a more energy efficient supply of compressed air. It doesn’t end there, as there are numerous projects under consideration that will drive the carbon footprint of Polysulphate down even further with the ultimate aspiration of achieving Net Zero!

Proven results of Polysulphate

ICL has conducted many trials globally and in North America to assess yield, quality, and nutrient use efficiency, and today, more and more farmers across North America are choosing OMRI-approved Polysulphate.

“Polysulphate has proven to be remarkably consistent and flexible to fit a wide range of North American cropping systems including potato and canola production in Canada, corn/soy rotations of the Midwest, and agave production in Mexico,” says Jason Haegele, ICL North American Agronomy Lead.

On average, across a wide range of crops and soil types, such as corn, soybean, potato, almond,  a variety of fruits, and cotton, Polysulphate trials have shown improved yield and quality. In addition, crops benefit from better establishment and root development, a more efficient source of sulfur, and other prolonged-release nutrient benefits.

Canola and other brassica crops that require a higher sulfur requirement have shown significant improvement in yield. The seed-safe attributes contribute to lower seeding rates and higher stand counts. Plus, adding Polysulphate also enables a healthier crop and increases the production of proteins and oil content.

Potato and other vegetable crops are also popular markets, and they have shown significant increases through the application of Polysulphate compared to other sources. In addition, there are many quality benefits such as skin finish (associated with the calcium in Polysulphate), increases in storage life, and reduction in storage losses.

There is also a growing trend of using Polysulphate on legume crops. Although legumes such as alfalfa do not require nitrogen, they still require crop nutrition to maximize yields. Sulfur will enhance the ability of these crops to fix atmospheric nitrogen as it is essential for the formation of nitrogenase, the enzyme responsible for nitrogen fixation.  Research also demonstrates higher biomass yield achieved. The growing use of legumes in grass mixes and encouraged use in regenerative practice and sustainable farm incentives is another compelling reason to use Polysulphate, especially given its compatibility with compost, manure, and other organic sources.

The use of fall or post-harvest applications of Polysulphate has also shown an additional response in yield and nutrient use efficiency (NUE). In the UK, a three-year study on winter wheat showed that fall applications of Polysulphate not only improved yield but also increased nitrogen uptake over the winter months.

Globally and locally, Polysulphate is proving to be a better choice for the environment while delivering additional revenue and profits to growers through increased marketable yields.