Impact of weather and management practices on GHG dynamics on an agricultural grassland in southern Finland

Agricultural management has recently drawn substantial attention as regenerative practices are showing their potential in enhancing soil quality and fertility, biodiversity, and carbon uptake from the atmosphere into the soil. In Nordic countries, there is a great number of farmers farming regeneratively. However, they are still a minority, and we are lacking scientific studies on the effects of various improved practices and their combination and use in practice in northern growing conditions.

We conducted a long-term study of an agricultural grassland ecosystem in southern Finland where regenerative management practices were implemented from 2018 onwards. We monitored H₂O and CO₂ fluxes with the eddy covariance method, and additionally, CH₄, N₂O and CO₂ with flux chambers. We also measured meteorological variables and several soil and vegetation parameters. We studied the impacts of different cutting heights for the silage grass on the ecosystem carbon sequestration. Furthermore, we utilised the data in model simulations with the grassland model BASGRA to study the carbon dynamics of the agricultural ecosystem in various weather conditions and with different management decisions. Our results indicate that the studied years, which were differing greatly from the long-term average weather, may have had a great impact on carbon dynamics on the grassland. Both empirical data and modelling demonstrated net carbon accumulation into the ecosystem under the selected improved practices.