Greenhouse gas emissions from cultivated and abandoned organic croplands in Finland
Marja Maljanen, Jyrki Hytönen, Päivi Mäkiranta, Jukka Alm, Kari Minkkinen, Jukka Laine, Pertti J. Martikainen
Abstract
Human activities have enhanced the emissions of carbon dioxide (CO 2 ) and nitrous oxide (N 2 O) from organic soils. Drained peat soils may turn into a source of CO 2 and N 2 O, whereas CH 4 emission may generally decrease after drainage. Agricultural use, including ploughing, fertilization and irrigation, further enhances the decomposition of peat, and CO 2 and N 2 O emissions. Cultivated organic soils are therefore significant sources of CO 2 and N 2 O. In this paper we report greenhouse gas emissions from cultivated organic soils, and from abandoned organic agricultural soils, i.e. from organic soils where cultivation practices have ceased. We found that CO 2 and N 2 O emissions from abandoned organic cropland soils do not generally decrease with time after agricultural practices have ceased, whereas CH 4 fluxes from the atmosphere into the soil may gradually increase after leaving cultivation.