Articles containing the keyword 'organic soil'

Soils have an essential role in ecosystem carbon balance. The soils of natural-like old unmanaged forests have been studied less than those of managed stands. In this study, we collected soil core samples and measured the soil carbon and nitrogen content of 27 old unmanaged forest soils in Southern and Eastern Finland. The results were compared against existing data from managed stands of similar site types. The data was also compared with earlier soil measurements from the same sites to look for any significant changes. The analysis resulted in an average of 2.58, 2.44 and 1.62 kg m^-2 of soil carbon and 0.087, 0.097 and 0.074 kg m^-2 of nitrogen in the organic layer, 0–10 cm of mineral soil layer and 10–20 cm of mineral soil layer, respectively. Carbon contents in the mineral soil layers were higher in unmanaged forests than in managed forests, but not in the organic-layer. Similarly for nitrogen, there was a significant difference between the unmanaged forests and the managed stands for both mineral soil layers, but not for the organic layer. There were no significant changes in soil carbon or nitrogen contents between the old and new measurements in the old unmanaged forests. The results align with the assumption that carbon and nitrogen content are higher in unmanaged forests than in managed forests due to their higher litter input on average, and more stable and cooler conditions. This means that old unmanaged forests have an important role as carbon storage and that the carbon storage is stable.

• Kumpu, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland https://orcid.org/0000-0001-9547-1697 E-mail: atte.kumpu@helsinki.fi
• Peltoniemi, Natural Resources Institute Finland (Luke); Bioeconomy and environment, Latokartanonkaari 9, FI-00790 Helsinki, Finland E-mail: mikko.peltoniemi@luke.fi
• Forsius, Finnish Environment Institute (Syke), Nature solutions, Latokartanonkaari 11, FI-00790 Helsinki, Finland https://orcid.org/0000-0003-0125-5120 E-mail: martin.forsius@syke.fi
• Mäkelä, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland https://orcid.org/0000-0001-9633-7350 E-mail: annikki.makela@helsinki.fi

Impact of drainage of organic soils in forest land on soil carbon (C) stock changes is of high interest not only to accurately estimate soil C stock changes, but also to provide scientifically based recommendations for forest land management in context of climate change mitigation. To improve knowledge about long-term impact of drainage on nutrient-rich organic soils in hemiboreal forests in Latvia, 50 research sites representing drained conditions (Oxalidosa turf. mel. (Kp) and Myrtillosa turf. mel. (Ks) forest site types) and undrained conditions as control areas (Caricoso-phragmitosa, Dryopterioso-caricosa and Filipendulosa forest site types) were selected. Soil C stock changes after drainage was evaluated by comparing current C stock in drained organic soils to theoretical C stock before drainage considering impact of soil subsidence. During the 53-years period after drainage, the peat subsidence was higher in nutrient-rich Kp forest site type compared to moderate nutrient-rich Ks forest site type (peat subsided by 37.0 ± 4.8 and 23.3 ± 4.8 cm, respectively). In nutrient-rich Kp forest site type, soil C stock decreased by 4.98 ± 1.58 Mg C ha^-1 yr^-1 after drainage, while no statistically significant changes in soil C stock (0.19 ± 1.31 Mg C ha^-1 yr^-1) were observed in moderate nutrient-rich soils in Ks forest site type. Thus, in Ks forest site type, the main driver of the peat subsidence was the physical compaction, while in Kp forest site type contribution of organic matter decomposition and consequent soil C losses to subsidence of the peat was significant.

• Lazdiņš, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia https://orcid.org/0000-0002-7169-2011 E-mail: andis.lazdins@silava.lv
• Lupiķis, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia E-mail: ainars.lupikis@inbox.lv
• Polmanis, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia https://orcid.org/0000-0003-2579-353X E-mail: kaspars.polmanis@silava.lv
• Bārdule, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia https://orcid.org/0000-0003-0961-5119 E-mail: arta.bardule@silava.lv
• Butlers, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia https://orcid.org/0000-0003-3118-1716 E-mail: aldis.butlers@silava.lv
• Kalēja, Latvian State Forest Research Institute ‘Silava’ (LSFRI Silava), Rigas str. 111, Salaspils, LV-2169, Latvia E-mail: santa.kaleja@silava.lv