CLIMATE - SOIL - BALTIC SEA

TWINWIN project

Project: How biodiversity impacts the ability of fields to store carbon

Duration: 2019 – 2021

Persons in charge: Jari Liski, Finnish Meteorological Institute, jari.liski@fmi.fi, Jussi Heinonsalo, University of Helsinki, jussi.heinonsalo@helsinki.fi & Laura Höijer, BSAG, laura.hoijer@bsag.fi

Consortium: Finnish Meteorological Institute, University of Helsinki, University of Tampere, University of Zürich, BSAG

Funder: Maj and Tor Nessling Foundation


Short description:

In this project, biodiversity is not only a goal but also a tool.

Biodiversity may increase carbon sequestration to agricultural soils in many ways. Diverse vegetation assimilate atmospheric CO2 efficiently and roots and root exudates transport C into different depths in soil. Plant diversity support diverse microbial communities that induces stable soil C formation. Increased soil organic matter content is essential for soil fertility and culturability and as a positive feedback, improved plant growth increases CO2 assimilation and flow to soil.

Modern agriculture where monocultures and chemical plant protection (e.g. herbicides, pesticides) are common has caused a decline in biodiversity in agricultural ecosystems. Currently, it is not well known how the increased plant diversity affect plant production and C sequestration.

The aim of the project is to investigate how much agricultural soil C sequestration can be increased by increasing plant diversity. In particular, we are interested in understanding which diversity-related processes are essential for soil C accumulation.

Biodiversity impacts on soil C sequestration will be investigated using field and greenhouse experiments and the most important factors will be included in the models that describe soil C cycling. In addition to the scientific work, a special emphasis is put in the outreach and communication.


Work packages (WP):

Work package (WP) 1 studies the impact of plant and microbial diversity on plant growth, pathogen resistance and C cycling. WP2 connects the knowledge on plant and microbial diversity to soil C sequestration and C stability. WP3 investigates, in collaboration with WP1 and 2, the greenhouse gas emission and other climate impacts with focus on C transfer between plants, soil and atmosphere. WP4 improves soil C modelling based on the information obtained in WPs 1-3.


Field experiment in Viikki, Helsinki:

In spring 2019, a large long-term field experiment was established in collaboration with TWINWIN and Viikki Research farm (Faculty of Agriculture and Forestry, University of Helsinki). The field experiment consists of seven different treatments comparing four different levels of biodiversity to conventional monoculture treatments and bare fallow. The cultivated plant species is barley. The eight undersown plant species are either all under barley, or in doubles or groups of four or eight species. Grouping is designed to take into account their functional traits (shallow or deep rooted, ability of N2-fixation or not). After barley harvest, conventional controls are tilled, and diversity treatments are left non-tilled until spring. The experiment consists of 60 plots.

The investigated parameters in the experiments are for instance plant cover, plant pathogens, yield, root and soil microbiology, soil chemistry and greenhouse gas exchange. The results are used to improve soil carbon model Yasso.

Photo: Anna-Liisa Laine

Read our news piece on the project.