Abstract. We experimented a gradual water table rise at a highly degraded agricultural peat soil site with plots of willow, forage and mixed vegetation (set-aside) in southern Finland. We measured the emissions of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) for four years. The mean annual ground water table depth was about 80, 40, 40 and 30 cm in 2019–2022, respectively. The results indicated that a 10 cm raise in the water table depth was able to slow down annual CO₂ emissions from soil respiration by 0.87 Mg CO₂-C ha^-1. CH₄ fluxes changed from uptake to emissions with a raise in the water table depth, and the maximum mean annual emission rate was 11 kg CH₄-C. Nitrous oxide emissions ranged from 2 to 33 kg N₂O-N ha^-1 year; they were high from bare soil in the beginning of the experiment but decreased towards the end of the experiment. Short rotation cropping of willow reached net sequestration of carbon before harvest, but all treatments and years showed net loss of carbon based on the net ecosystem carbon balance. Overall, the short rotation coppice of willow had the most favourable carbon and greenhouse gas balance over the years (10 Mg CO₂ eq. on the average over four years). The total greenhouse gas balance of the forage and set-aside treatments did not go under 27 Mg CO₂ eq. ha^-1 year^-1 highlighting the challenge in curbing peat decomposition in highly degraded cultivated peatlands.

中文翻译：

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耕作泥炭土场地四年适度再润湿期间的碳平衡以及甲烷和一氧化二氮的排放

摘要。我们在芬兰南部的一个高度退化的农业泥炭土地点试验了地下水位逐渐上升的方法，其中有柳树、饲料和混合植被（预留）的地块。我们测量了四年来二氧化碳 (CO ₂ )、甲烷 (CH ₄ ) 和一氧化二氮 (N ₂ O) 的排放量。 2019-2022年年平均地下水位深度分别约为80、40、40和30厘米。结果表明，地下水位深度每升高10 cm，土壤呼吸引起的CO _{2年排放量可减少0.87 Mg CO 2} -C ha ^-1。随着地下水位深度的增加，CH _{4通量从吸收变为排放，年平均排放量最大为11 kg CH 4} -C。一氧化二氮排放量为2至33 kg N ₂ O-N ha ^-1年；在实验开始时，它们相对于裸土较高，但在实验结束时有所下降。柳树的短轮作在收获前达到了碳的净固存，但所有处理和年份都显示出基于净生态系统碳平衡的碳净损失。总体而言，短轮伐柳林多年来具有最有利的碳和温室气体平衡（四年平均为10 Mg CO ₂当量）。饲料和备用处理的总温室气体平衡没有低于 27 Mg CO ₂ eq。 ha ^-1年^-1强调了在高度退化的耕作泥炭地中遏制泥炭分解所面临的挑战。