Abstract. Raising the water table is an effective way to abate greenhouse gas emissions from cultivated peat soils. 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 4 years. The mean annual groundwater table depth was about 54, 40, 40 and 30 cm in 2019–2022, respectively. The results indicated that a 10 cm rise 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 rise in the water table depth, and the maximum mean annual emission rate was 11 kg CH4-C ha−1. Nitrous oxide emissions ranged from 2 to 33 kg N2O-N ha−1 yr−1; they were high in bare soil at 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 a 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 average over 4 years). The total greenhouse gas balance of the forage and set-aside treatments did not go under 27 Mg CO2 eq. ha−1 yr−1, highlighting the challenge in curbing peat decomposition in highly degraded cultivated peatlands.

中文翻译：

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作物类型对再湿化耕地泥炭地温室气体 （GHG） 排放的影响


摘要。提高地下水位是减少耕地泥炭土壤温室气体排放的有效方法。我们在芬兰南部一个高度退化的农业泥炭土壤地块上试验了地下水位逐渐上升的试验，该地块有柳树、牧草和混合植被（预留）。我们测量了 4 年的二氧化碳 （CO2）、甲烷 （CH4） 和一氧化二氮 （N2O） 的排放量。2019—2022 年地下水位年平均深度分别为 54、40、40 和 30 厘米。结果表明，地下水位深度每升高 10 cm，土壤呼吸每年的 CO2 排放量就会减慢 0.87 Mg CO2-C ha-1。CH4 通量随地下水位深度的增加而从吸收到排放而变化，最大年平均排放速率为 11 kg CH4-C ha-1。一氧化二氮排放范围为 2 至 33 kg N2O-N ha-1 yr-1;它们在实验开始时在裸土中较高，但在实验结束时下降。柳树的短轮作在收获前达到了碳的净封存量，但根据生态系统的净碳平衡，所有处理和年份都表明碳的净损失。总体而言，柳树的短轮作多年来具有最有利的碳和温室气体平衡（4 年平均 10 毫克二氧化碳当量）。牧草和预留处理的总温室气体平衡未低于 27 Mg CO2 当量 ha-1 yr-1，这凸显了在高度退化的泥炭地中遏制泥炭分解的挑战。