Reed - crop of the future

Reed is usually only used as roughage as an emergency solution when there are poor harvests, for example during drought. In this project, we want to investigate how and when the reed should be harvested to function as feed and how it can best be preserved through ensiling. We will also investigate whether the feed value can be improved through various physical and biological process methods. The overall aim is to recover nutrients from land and water that would otherwise end up in the Baltic Sea.

Background

During the last hundred years, Sweden and other countries around the Baltic Sea have imported large amounts of phosphorus and nitrogen, so-called nutrient salts, mainly through commercial fertiliser, animal feed and food. Over the years, this surplus has, via waterways, ended up in the Baltic Sea, where it contributes to eutrophication with overgrown bays, algal blooms and dead bottoms as a result.

To reduce this problem, we have for a long time implemented a number of measures such as municipal treatment plants, edge zones, wetlands and more. Common to all of these, however, is that they do not generate any income but instead costs for the society.

Reed grow naturally both on wetlands and in the riparian zone, even right up to the fields. Harvesting reed can thereby both function as an environmental measure, in the form of a catch crop, and generate an income such as for example feed to animals.

Photo: Anders Kiessling

Reed has a nutritional value comparable to hay and straw, depending on when and how you harvest, but significantly harder structure. An important part of the project is to investigate whether we can preserve the reed, in order to be able to use them as feed in the winter, through ensiling. This is done, for example, by packing the reed in round bales, adding organic acids or bacterial cultures and then enclosing it in plastic film. The end result is the white balls that most people recognize from fields around the country.

Overall, reed has properties that make it interesting both as a so-called catch crop of plant nutrition and as feed. As a feed, it is best suited to animals with lower nutritional requirements, e.g horses and non-producing dairy cows, heifers and beef cattle.

The project

During the summer of 2019, reed have been collected from various places, near the field, near pasture, in Mälaren's bays and all the way to the coastal strip. Reed are traditionally harvested in late autumn or winter when all the nutrients have gone down into the roots.

In this project we have collected reed both early in the season and late. We have also collected a second harvest, i.e. that which has grown up after harvest in early summer, to see how the nutritional value varies with time of year, all similar to harvesting hay. These reed samples will be analyzed to map the nutrient content (photo: Anders Kiessling).

In addition to the reed being analyzed as a whole, leaves and stem will be analyzed separately. This is because the leaves are significantly more nutritious than the stem. The strain may therefore be better suited to other things such as soil improvement and other "outside the box" possibilities, such as straws.

Anders Kiessling, professor of aquaculture at the Department of Applied Animal Science and Welfare, SLU, talks about reed's potential as animal feed for horses and non-milking cattle in an article from SVT Nyheter (in Swedish).

The spread of reed

Today, there are many overgrown bays with reed and thus quite a lot of wild reed to harvest (apart from reed in fields and wetlands). Along our coasts there are more than 200,000 hectares of reed, all lakes not counted. Reed act as protection for both fish and birds and therefore must be harvested with respect for nature. Örjan Östman, Aquatic Resources, Coastal Lab, SLU is currently working together with several stakeholders on how to harvest reed to benefit both fish and birds.

In this video Örjan Östman talks about reed and harvest of reed in Sandikafjärden (subtitles in English).

Photo: Anders Kiessling

Reed are an important spawning environment for many of our most common fish species along the coast. However, although large reed belts can protect and provide food for fish eggs and fry, too large contiguous areas can also inhibit the growth of predatory fish. In experiments in North American lakes, reed clearing and the creation of reed streets and reed mosaics have been shown to have positive effects on the growth of predatory fish. Now we want to investigate whether this can be a method to improve the situation for predatory fish such as perch and pike also in Swedish coastal waters.

In Österby and Västerbyfjärden on Gräsö in northern Roslagen, approx. 4 ha of reed were cut in the summer of 2019, partly to improve access for boats but also to create streets with more open water surface in continuous reed seas to increase the mosaic of reed and open water. The aim is to improve the stocks of primarily perch and pike. A first test fishing that was done before the reed clearing in 2019 shows that the fish in the bays are dominated by a high proportion of roach and spiny which is typical of over-fertilized bays along the coast. SLU will for at least two more years monitor how the fish community changes after the reed clearing.

Photo: Örjan Östman

Open House on Baltic Sea Day

As part of the project Rikare vatten SLU participated in an Open House during the Baltic Sea Day on August 29, 2024. There were about thirty visitors, both private individuals and representatives of various organizations, as well as a class from Marina läroverket.

Fredrik Holmén, Sjöutsikt AB, demonstrated reed harvesting from the water with small bale ensiling. Vallentuna 4H participated and talked about how they use reed silage for their horses. Örjan Östman (SLU Aqua), William Ashworth (doctoral student at SLU Aqua and THV), Malin Connysson (HBIO) and Bengt Ove Rustas (THV) talked about the effect of reed harvesting on aquatic ecosystems and how it works as feed for horses and cattle. The visitors were mainly interested in reed silage as feed for horses.

The picture shows William Ashworth, Örjan Östman and Malin Connysson at SLU's stand. Photo: Bengt-Ove Rustas.

The reed harvester both harvest and chop the reed so that it can be ensiled into feed. Photo: Bengt-Ove Rustas.

More reed research

Several researchers at SLU have also previously taken an interest in reed in agriculture.

Thomas Prade has worked both with reed as a catch crop and as a substrate for biogas:

Wetlands as biomass producers

Skördad våtmarksvegetation renar vattnet bättre från närsalter!

Vass på våtmarker ger dubbla miljövinster

Malin Hultberg has worked with reed as a substrate in the cultivation of edible mushrooms:
Adding benefit to wetlands – Valorization of harvested common reed
through mushroom production 

Bengt-Ove Rustas, Cecilia Müller and William Ashworth study reed as feed for horses and cattle:
Vass som foder till hästar och nötkreatur

Project group

Anders Kiessling, Applied Animal Science and Welfare, SLU

Bengt-Ove Rustas, Applied Animal Science and Welfare, SLU

Cecilia Müller, Applied Animal Science and Welfare, SLU

Örjan Östman, Aquatic Resources, SLU

Pär Svärdson, Apotea

Alexandra Lundegård, ALEQUI Equestrian AB

Martin Karlsson and Martin Reutergård, Ecopelag ekonomisk förening

The project is also financially supported by Kiviks Musteri.

Reed project in media (in Swedish):

Apotea-grundaren Pär Svärdsons nya satsning – ska rädda Östersjön, Breakit

Apotea-grundaren vill göra foder av vass, Land Lantbruk

SLU-forskare: Vass kan bli framtidens foder, ATL TV