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2021 > 12

As we near the end of the year, we wanted to thank you for your continued commitment and perseverance through 2021! There are many things to be thankful for this year including reconnecting in person with the SITES community and continued funding for years to come. We look forward to keeping the monument and continued journey with you in 2022! God Jul! Enjoy the holidays and best wishes for 2022 from the SITES Secretariat! 

At Svartberget Research Station, an ongoing soil project, investigating soil organic carbon and nitrogen, uses plastic balls added to the soil pit to estimate pit volume.  

Using "bollhav" balls to measure pit volume (Photo: Craig King) Using "bollhav" balls to measure pit volume (Photo: Craig King)

Soil is a major component of the terrestrial carbon cycle. Thus, monitoring temporal change in Soil Organic Carbon (SOC) and Nitrogen (SON) stock isrequired to close the ecosystem mass balance of these elements and to assess the role of terrestrial ecosystems in the global carbon cycle. 
 
In an on-going project, with the aim to monitor the SOC and SON stocks within the target area of the Eddy Covariance (EC) flux tower at Svartberget soil samples have been collected and prepared. The project involves organizing student field assistants working on the project, collecting soil samples in the field, photographing the soil pit, setting up a soil drying lab, liaising with the central laboratory and following the protocol to process the soil samples (i.e., labelling, drying, sample weighing, separation of soil stones and vegetation).  

The SOC and SON stocks for the first meter (0 to 100 cm) of the soil profile is determined from measurements of soil organic carbon and nitrogen content as well as bulk density of the soil. The SOC and SON content is analysed by a central laboratory, while the station team measures the soil density.  

Johan Westin, Experiment Group Leader at the Unit for Field-based Forest Research, offers some practical advice about the technique used for pit volume, 

“Have you ever taken on the task to estimate the bulk density of all of what you have dug up from a 1 m deep pit in a spruce forest in northern Scandinavia? In theory, it is easy. Just dig a rectangular shaped pit on the flat soil down to a one meter. Measure width and length. Weigh everything that you have dug up. Move on to next pit.

In reality though, there are stones, rocks, roots, sand, clay and so on. The pit seldom has a regular shape so the task to measure the volume is suddenly not so easy. This may be the point where all the hours you have spent with your children in a “bollhav” (ball pit) somewhere suddenly pays off. Buy balls and bring the “bollhav” to the field (leave the kids at home), fill the pit with the balls and count the number of balls. Calculate the pit volume. Move on to next pit. It’s a colourful approach.”   

The onset of ice at Lake Erken occurred on Dec 6th this year, which is a record in recent years, but put in the historical context not so unusual.

Current ice conditions on Lake Erekn as seen from the west-facing live camera on 2021-12-09. Current ice conditions on Lake Erekn as seen from the west-facing live camera on 2021-12-09.

Visual observations of the onset and loss of Lake Erken’s ice cover began in 1940 and continues today, now with the assistance of the same camera used for SITES vegetation phenology monitoring (link to live webcams on the lake). The effects of ongoing climate change are leading to a clear trend in decreasing ice cover as shown for Lake Erken in graph a below. In fact, the last three years have had some of the shortest ice durations on record, with the winter of 2019-2020 having the shortest duration on record of only five days.

With this in mind, it is exciting that this year there appears to be an unusually early onset of ice cover, taking place already on Dec 6, 2021. When put into the historical context (as seen in graph b below) the ice cover did in fact start early, but this year’s early onset of ice is not so unusual. It is the 17th earliest ice onset (tied with 1979) of the data recorded at Erken. But how to interpret this against a clear trend of a later onset? This illustrates the concept that “Stationarity Is Dead”1 a problem the climate change researchers and water managers must now consider in their day to day work.
 
1Milly, P. C. D. et al. Stationarity Is Dead: Whither Water Management? Science 319, 573-574, doi:10.1126/science.1151915 (2008).
 

The old pea variety ‘väse’ in full bloom. (Photo: Dylan Wallman). The old pea variety ‘väse’ in full bloom. (Photo: Dylan Wallman).

A project focusing on intercropping of faba beans and peas has been initiated at SITES Lönnstorp Research Station. This year was the first of the three-year project period.

The aim of the project is to study and optimize the intercropping of faba beans and peas. The trials are conducted by Dylan Wallman as parts of his licentiate education at the department of Biosystems and Technology at SLU Alnarp. The goal is to investigate whether intercropping of peas and faba beans can provide higher and more stable yields in organic production compared to individual cropping of each. In the project, both seed and biomass yield are measured, and other agronomical aspects relevant for organic farming and intercropping are also assessed. 

This year was agriculturally a relatively good year, although there could have been more precipitation, which would have especially benefited the faba beans. The results from this first year will provide clues on how to further develop the trial design for the two upcoming years. Intercropping of faba beans and peas has historically been performed in Sweden, but is nowadays very rare, both in production and research. By observing the two crops growing together a lot can be learned; on a weekly basis there are surprises, and what you think is the best combination of varieties in the early summer can very much be the worst by the end of the season.  

This project studies both modern and old varieties of faba beans and peas. Historically, since peas often were intercropped with either cereals or faba beans, the older varieties are more adapted to grow with a companion crop than by themselves. Many of the older varieties also have culinary properties that can contribute to increasing the demand for locally produced legumes. At the same time, larger local harvests of protein-rich plants allow for a reduction in imports of soya beans for animal feed. Therefore, the project is also a step towards shortening the distance between the production and consumption of food and facilitating the transition to more plant-based protein in human diets. 

See more about the project in the research video (in Swedish with English subtitles): Intercropping of fava bean and pea in organic farming systems

The trials are conducted at the organic experimental fields at SITES Lönnstorp. Supervisors are Georg Carlsson (SLU), Åsa Grimberg (SLU), and Matti Wiking Leino (SU). The project is funded by Ekhagastiftelsen. 

Intercropping of faba bean and peas at the organic experimental fields at SITES Lönnstorp (faba bean to the left and pea to the right). Photo: Dylan Wallman.
Intercropping of faba bean and peas at the organic experimental fields at SITES Lönnstorp (faba bean to the left and pea to the right). Photo: Dylan Wallman.

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