Browsing by Subject "kosteikkoviljely"

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  • Lahtinen, Laura (Helsingin yliopisto, 2020)
    Tiivistelmä – Referat – Abstract Finland has one of the highest percentage of peatlands in the world, so peatlands have inevitably been taken into cultivation use. Agricultural peatlands however generate a significant amount of greenhouse gas emissions, especially carbon dioxide (CO2) and nitrous oxide (N2O). Thus, agricultural usage of peatlands is considered one of the most unfavorable uses of land for the climate. Peatlands have been drained in order to improve food services, which in turn negatively affects other ecosystem services. Some of the ecosystem services can be restored by rewetting the land. If rewetting is combined with paludiculture, the land’s production services will not be lost. The goal of this thesis was to compare the greenhouse gas emissions and the carbon footprints of two paludicultural products’ life cycles. The compared products were cattail insulation board and common reed seedbed. The intent was to produce comparable data on different options for the paludiculture of agricultural peatlands. The data obtained from the life cycle assessment of the products was compared to similar non-paladiculture products, rock wool insulation board and horticultural peat. The material was reviewed with the life cycle assessment method following the ISO 144040 standard, but the work was limited only on climatic effects. Based on the analysis, key sources of climatic effect in the product system were identified and means to reduce them were considered. The intent was to calculate the carbon footprint and to identify where in the life cycle the emissions were generated. After this, the portion of agricultural peatlands in in the life cycle’s environmental effects was estimated. The material for this thesis was collected from scientific literature and life cycle assessment databases (ecoinvent v.3). The material of peatlands and other parts of the process were collected from studies made around the world in the boreal and temperate zone. A model was assembled based on the material, which included all phases of the paludicultural product’s life cycle and their effects on the climate with regards to carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), The emissions in a paludicultural product’s life cycle are mostly generated during its cultivation and processing. The carbon footprint of both paludicultural products was most likely negative, so they slowed down climate change. Based on the study, the most benefit was achieved by moving the cultivation of barley from agricultural peatlands to mineral soil and replacing it with paludiculture. By using paludiculture, it’s possible to reduce greenhouse gas emissions of agricultural peatlands, but it won’t achieve carbon neutrality. The study had a significant amount of uncertainty, so further studies are recommended especially in Finland.
  • Niemi, Jari (Helsingin yliopisto, 2020)
    The aim of this study was to investigate if the drainage-based utilization of agricultural peatlands, associated with heavy greenhouse gas (GHG) emissions, really meets the goals of the farmers, and to investigate how well alternatives with lesser GHG emissions could fit the farmers’ needs. Finland has obligations, both national and from European Union, to reduce its total GHG emissions from the levels of 1990 by 39 % until 2030, and 80 % until 2050. Ten percent of Finland’s total GHG emissions come from agricultural sector. Agricultural organic soils represent only about 10 % of total agricultural land in Finland, but it is estimated that the GHG emissions from these organic soils make up to 50-60 % of the total GHG emissions of the whole agricultural sector. The low water table in traditional drainage-based utilization of agricultural peatlands causes rapid decomposition of peat, which leads to high GHG emissions, leaching of nutrients, subsidence and to numerous problems on the fields. According to literature review done, raising of the water table is the most efficient way to reduce GHG emissions on agricultural peatlands, but the raised water table limits the use of traditional crops like cereals. Restoration of the peatland, paludiculture and afforestation have been suggested as alternative uses of these agricultural peatlands in literature. In this study, multi-criteria decision analysis was used to compare different uses of agricultural peatlands in the light of varying goals. Twelve different forms of peatland utilization were selected for the comparison, and these included forms of utilization with both high and low water tables. Firstly, it was investigated what kind of indicators can be used to assess the performance of the different types of utilization, and values for those indicators were gathered from the literature if possible. Weighting of the indicators in relation to the goals of the farmers was planned to be carried out with a questionnaire, but as we did not manage to get any answers from the farmers, the multi-criteria decision analysis was done with weightings collected both from a group of scientists and from a simulation. Traditional forms of drainage-based farming scored well on financial and productional indicators, but they lacked on regulating and cultural indicators. In both analyses with the weighting given by the group of scientists and by simulation, utilization forms of peatlands with high water table were selected as the best alternative for agricultural peatland management significantly more often than the deeply drained alternatives. With the weighting done by the group of scientists the deeply drained forms were selected not once as the best alternative for peatland utilization, and with the weightings extracted from the simulation in only 3,5 % of the cases a deeply drained form of utilization was selected as a best alternative. These multi-criteria decision analyses show, that the wet forms of peatland utilization have a great potential to be selected as the best alternatives of agricultural peatland utilization also with weighting profiles that put heavy weight also in financial indicators, although this requires the market to the alternative materials to be developed. The policy concerning agricultural subsidies likely affects financial attractiveness of the utilization alternatives of peatlands by great extent. Further long-term research of paludiculture is still needed, and field studies on paludiculture should also be started in Finland to improve the assessment of wet peatland use on most indicators.