Improving potato quality with Polysulphate

(Sponsored) Better plant nutrition means higher quality potatoes. The challenge, though, is ensuring that the necessary nutrients are available exactly when tubers need them throughout the growing season. Careful calculation for and programmatic application of nutrients is just one set of calculations that potato growers have to worry about in a sea of challenges for the potato season.

Photo of potatoes on a beltA new product on the market, Polysulphate, is designed to make nutrients more available to tubers with a single application. The manufacturer, ICL, says that Polysulphate improves the cell structure in potato skins, making them more durable; less bruising, damage and storage shrink were reported in their internal trials. Additionally, they saw lower amounts of sugar in the tubers and less acrylamide formation through the frying process.

Polysulphate is a mineral fertilizer that contains calcium, potassium, magnesium and sulfur in a highly available, homogeneous granule. It is designed to enhance the existing nutrients growers are using and to improve availability of the nutrients when the plants need them.

Mid-Michigan Agronomy’s Polysulphate Study

Agronomist Rob Schafer of Mid- Michigan Agronomy LLC, tested the product during the 2021 growing season on multiple varieties, including those for chips and table stock, on farms in North Carolina, Illinois, Indiana and Michigan. The acreage at these farms ranged from 300 to 6,000 acres.

In the chip world, major processors are seeking smaller potatoes in the 2- to 2.5” diameter range, so one thing Schafer tested was if Polysulphate would increase the yield of these tiny tubers rather than increasing the diameter. At each farm, Schafer had the growers include Polysulphate in their spreaders to broadcast with other pre-plant nutrients. The conventional spreaders handle Polysulphate well without any adjustments needed. No other changes were made to the growers’ existing programs.

Study results

Schafer received preliminary results as of the time of press; these results show that for the smaller chip potatoes, yield increased while tuber size remained consistent. With all types, the farms had an increase of 20,000 tubers per acre, which increased total bags of potatoes by 20%.

“A large part of agronomy is getting nutrients in place to feed a crop when the crop actually wants it. If we miss those windows, our yields go down as a result.

With Polysulphate, you do not have to adjust the program at all. Just add it with your preplant broadcast,” Schafer said.

How Polysulphate Works

When applied with pre-plant or pre-hilling broadcast applications, Polysulphate’s sulfate-based nutrients are available to plants exactly when they’re needed. polysulphate logo in green and yellowCalcium, which is often overlooked in its importance to tuber development, is “a powerful soil remedy for balancing cation exchange capacity. If you have lots of sodium, aluminum and bicarbonate, calcium is a very effective tool to offset these from agronomic capacity,” said Anthony Duttle, agronomy lead for North America with ICL.

The granular form of the fertilizer has a sustained release corresponding closely with the nutrients and timing that potatoes need, especially in the light soils where potatoes are usually grown.

As the plants’ nutrient demands wane and wax throughout the season, Polysulphate’s nutrition is available at the levels that potatoes need. It is an easy way to get a net gain in quality and nutrition for tubers.

In regions with high levels of bicarbonates in the soil that need balance in order to reduce salinity in soil, the calcium in Polysulphate helps to create that balance.

Environmental Impact and Organic Growing, Globally

A naturally mined mineral found in Northeast England, Polysulphate has a low carbon footprint. It is OMRI certified, Eco-Cert, CA Ag certified, WA Ag certified and its inclusion is allowed in growing potatoes for any market across the globe.

About ICL

ICL is one of the world’s largest fertilizer companies. We provide retailers, growers and manufacturers with a wide range of high-performance plant nutrition solutions which help grow healthier and stronger crops in a sustainableICL logo in teal and blue way. Polysulphate fertilizer is one of the greenest, multi-nutrient fertilizers in the world containing four essential macronutrients: sulfur, potassium, magnesium and calcium.

To learn more about Polysulphate, visit

© 2022 ICL Group

75 Applewood Dr. Ste. A
P.O. Box 128
Sparta, MI 49345


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