Gypsum has halved phosphorus leaching from treated fields along the River Vantaa – the John Nurminen Foundation says further funding is critical

In the River Vantaa Gypsum Project led by the John Nurminen Foundation, treating fields with gypsum has once again proven effective as a way of rapidly reducing nutrient loading. The Foundation calls on decisionmakers to continue public funding for this treatment after the Programme for Improved Water Protection has ended.

The River Vantaa Gypsum Project was implemented as a partnership between the public and private sectors. The John Nurminen Foundation’s supporters and project partners financed just over 70 per cent of the project and the Ministry of the Environment just under 30 per cent.

“We were convinced of the effectiveness of treating fields with gypsum back in 2014, and have since been working to make gypsum treatment a standard option in Finnish water protection. Using gypsum treatment on the large scale required by the River Vantaa project would not have been possible without considerable investments from the Foundation’s private supporters, the Ministry of the Environment’s involvement and expert project partners,” says Annamari Arrakoski-Engardt, CEO of the John Nurminen Foundation.

The River Vantaa Gypsum Project, which ran from 2018 to 2020, exceeded its targets: the project treated more than 3,600 hectares, that is, about 10 per cent of the arable land in the River Vantaa catchment area. Treating fields with gypsum halved phosphorus leaching, which in turn reduced eutrophication in coastal waters in both the River Vantaa and the Gulf of Finland. As in previous trials, gypsum treatment proved to be an inexpensive way of protecting bodies of water. The results confirm that treating fields with gypsum can significantly cut nutrient loading from agriculture. It should therefore play a key role in achieving Finland’s water protection targets.

Gypsum treatment yields good results in reducing nutrient leaching

The gypsum treatment carried out during the River Vantaa Gypsum Project halved phosphorus leaching in the parcels of land that were treated. The treatment involved spreading four tons of gypsum per hectare of land. The treatment of a total of 3,615 hectares of arable land is estimated to reduce phosphorus leaching from the River Vantaa catchment area by an estimated 8,500–10,500 kg during 2018–2025. Gypsum does not hinder phosphorus intake in plants or have an adverse effect on crop yields.

“Clearer water in the monitoring area was one concrete, visible impact of using gypsum. Treating all of the suitable arable land in the River Vantaa catchment area would have the potential to reduce phosphorus loading by an amount equivalent to more than a fifth of the annual load arising from human activity. Gypsum treatment would also be suitable for treating fields in many other coastal areas, although it should not be used in lake catchment areas,” says researcher Pasi Valkama from the Water Protection Association of the River Vantaa and Helsinki Region.

73 farms, two cities and one educational establishment took part in the gypsum treatment. Its impact on run-off water quality was monitored at a measuring station on the River Lepsämä, as approximately 40 per cent (330 hectares) of the upstream fields were treated. The change in phosphorus loading throughout the entire River Vantaa catchment area was assessed on the basis of results obtained from the monitoring area.

“The cost-effectiveness of water protection is an important criterion in the John Nurminen Foundation’s projects. In the River Vantaa project, we received a large proportion of the gypsum as a donation from Yara, which meant that we paid EUR 57 per kilo of phosphorus reduced by gypsum treatment. Using the market price of gypsum, this would have been about EUR 80 per kilo of phosphorus reduced, which is still markedly less than the average cost for water protection measures, about EUR 200 per kilo of phosphorus reduced,” says Marjukka Porvari, Director of the Clean Baltic Sea projects at the John Nurminen Foundation.

The project also included a small-scale natural gypsum pilot for about 80 hectares of land used for organic production. However, the natural gypsum that is approved for use in organic fields was quite difficult to obtain and its quality varied greatly between sources. The per-kilo cost of reducing phosphorus using natural gypsum was twice that of using the gypsum formed as a by-product of fertiliser production.

Water protection measures do not interfere with trout breeding

A fish stock study (which employed electrofishing and tested buried roe) indicated that gypsum treatment does not weaken fish stocks, and water quality also remains suitable for trout breeding in areas affected by gypsum treated fields.

Finland will not reach its water protection targets without gypsum – further funding required

Gypsum treatment will be carried out in 2020–2024 as part of the Programme for Improved Water Protection in Southwest Finland. This programme will be funded by the Ministry of the Environment and led by the Centre for Economic Development, Transport and the Environment of Southwest Finland. The aim is to spread gypsum over at least 50,000 hectares in the Archipelago Sea catchment area. In order to reach the targets set in the Helsinki Convention on the Protection of the Marine Environment of the Baltic Sea Area and other water protection programmes, a larger area of the Archipelago Sea will need to be treated with gypsum.

“The parties and farmers involved in the project have done valuable work for the good of the River Vantaa. Spreading gypsum has proven to be an effective way of protecting water, and this year the Programme for Improved Water Protection expanded its use of gypsum to fields in the Archipelago Sea catchment area. In order to achieve good water quality, cooperation and a wide range of other measures will also be required in addition to gypsum treatment. We have a duty to take care of our waterways. We must secure permanent resources for this work in the future as well,” says Krista Mikkonen, Minister of the Environment and Climate Change.

“National public funding for gypsum treatment should be continued, and gypsum treatment extended to new areas. We estimate that Finland has almost a million hectares of arable land that would be suitable for gypsum treatment. By treating these fields, Finland could meet both its international commitments to the Baltic Marine Environment Protection Commission and its national targets for Baltic Sea protection. This opportunity should not be missed,” says Markku Ollikainen, Research Director and Emeritus Professor of Environmental and Resource Economics at the University of Helsinki.

The practices created during the River Vantaa project would also make a suitable operating model for other EU-funded gypsum treatment.

“The most cost-effective form of agricultural water protection – treating fields with gypsum – should be included in the EU agricultural subsidy system. Gypsum could be included in the subsidy system as a so-called non-productive investment that would benefit the environment but not increase production. As in the River Vantaa project, farmers could easily acquire gypsum, delivery and spreading services through the agricultural trade, and the EU could compensate all those who have chosen to take this action. When choosing parcels of arable land, we could prioritise erosion-sensitive parcels with high levels of phosphorus in order to achieve maximum benefit in water protection,” says Anna Saarentaus, Project Manager, Clean Baltic Sea projects at the John Nurminen Foundation.

Further research on different soil types and tillage methods

Gypsum treatment has proven to be an effective method of protecting water in clay soils. However, the project identified a need for further research, particularly with regard to the effectiveness and effectiveness period of gypsum in different types of soils and tillage methods. The combined effect of gypsum with chalk or manure also requires further study.

“The better we understand how effective gypsum is in different conditions, the easier it will be to prevent phosphorus from ending up in the Baltic Sea with the limited resources available,” says Petri Ekholm from the Finnish Environment Institute.

The River Vantaa Gypsum Project was implemented by the John Nurminen Foundation, the Water Protection Association of the River Vantaa and Helsinki Region, the Finnish Environment Institute and the University of Helsinki. The project was funded by the Ministry of the Environment and supporters of the John Nurminen Foundation. Yara donated the recycled gypsum that was used in the project during 2019 and 2020.

Further information:

Marjukka Porvari
Director of the Clean Baltic Sea projects
John Nurminen Foundation
Tel.: +358 41 5491535,

Pasi Valkama
The Water Protection Association of the Vantaa River and Helsinki Region (VHVSY)
Tel.: +358 44 767 1394

Petri Ekholm
Senior Research Scientist
The Finnish Environment Institute (SYKE)
Tel.: +358 295 251102,

Markku Ollikainen
The University of Helsinki
Tel.: +358 2941 58065

Laura Saijonmaa
Senior Ministerial Adviser
Ministry of the Environment
Tel: +358 295250261

John Nurminen Foundation – Baltic Sea protection and marine culture
Founded in 1992, the mission of the John Nurminen Foundation www.johnnurmisensaatio.fi/enis to save the Baltic Sea and its heritage to future generations. The Foundation has been awarded for its work as a conveyor of culture and producer of marine content. The goal of the Foundation’s Clean Baltic Sea projects is to improve the condition of the Baltic Sea with concrete measures that reduce the load and environmental risks faced by the sea. Our work is guided by measurable results and impact.


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