Harvest time, domestic gypsum supply and new areas of use

Construction of draining system, with gypsum filter for reduced phosphorus runoff.

Great conditions for field trials

In the GYPREG field trials in Sweden, we are testing how gypsum spreading on fields can give the soil better structure and reduced phosphorus leakage. Gypsum is widely used in Finland, while structural lime is a much more common alternative in Sweden. Our trials include both gypsum and structural lime, to provide an understanding of the similarities and differences between them.

The soil amendments were applied in September 2024 in three different areas. During summer season 2025, spring barley has been growing in the trial fields. All three trials have now been harvested and sampled. This year’s weather has given perfect conditions for growth and harvest, creating great opportunities for useful results. First results from soil and crop samples will come in November. The last group of soil samples will be in laboratory for rain simulation during the coming winter, giving us answers on the nutrient leaching effect in April 2026. To be continued!

Gypsum used in new ways

In the GYPREG project, gypsum is evaluated as an alternative to structure lime for spreading on farmlands. In collaboration with the environmental coordinators at Västervik municipality, we are now testing gypsum in an additional application. In September, 15 000 m2 of farmland was drained and equipped with gypsum filter ditches.

Using a layer of structure lime while filling covered drainage pipes is an established measure in Sweden to reduce phosphorus leakage from farmland. Usually, this involves mixing structure lime into the soil when newly installed subsurface drains are covered. The lime improves drainage and captures phosphorus that would otherwise leak into the drainage system and further into surrounding watercourses. By taking water samples from the individual drainage pipes in the coming years, we will now be able to find out what effect the gypsum has on phosphorus leakage from the field. This is an important step toward the potential scaling up of gypsum use on Swedish farmland.

Gypsum recycling for agricultural use

Finding suitable gypsum supply, preferably domestic, is another crucial part of the GYPREG project. In Q3, our Swedish business manager has involved and visited companies in the gypsum recycling industry. In Falköping, large amounts of gypsum waste are sorted, milled and controlled in the recycling process turning the waste into useful gypsum material. Inspiring to see the process and the potential for scaling up. Eurogypsum, the European federation representing the gypsum product manufacturing industry, has developed quality criteria for recycled gypsum. It covers both technical parameters and health, safety and environmental parameters. This documentation will be a useful tool further on in the project, for ensuring safe use of recycled gypsum also for agricultural use.