Quantification of harmful nitrous oxide (N₂O) emissions from soils is essential for mitigation measures. An important N₂O producing and reducing process in soils is denitrification, which shows deceased rates at low pH. No clear relationship between N₂O emissions and soil pH has yet been established because also the relative contribution of N₂O as the denitrification end product decreases with pH. Our aim was to show the net effect of soil pH on N₂O production and emission. Therefore, experiments were designed to investigate the effects of pH on NO₃⁻ reduction, N₂O production and reduction and N₂ production in incubations with pH values set between 4 and 7. Furthermore, field measurements of soil pH and N₂O emissions were carried out. In incubations, NO₃⁻ reduction and N₂ production rates increased with pH and net N₂O production rate was highest at pH 5. N₂O reduction to N₂ was halted until NO₃⁻ was depleted at low pH values, resulting in a built up of N₂O. As a consequence, N₂O:N₂ production ratio decreased exponentially with pH. N₂O reduction appeared therefore more important than N₂O production in explaining net N₂O production rates. In the field, a negative exponential relationship for soil pH against N₂O emissions was observed. Soil pH could therefore be used as a predictive tool for average N₂O emissions in the studied ecosystem. The occurrence of low pH spots may explain N₂O emission hotspot occurrence. Future studies should focus on the mechanism behind small scale soil pH variability and the effect of manipulating the pH of soils.

中文翻译：

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低土壤pH降低的N2O还原量会导致河岸生态系统中N2O排放量较高。

量化土壤中有害的一氧化二氮（N ₂ O）排放对于缓解措施至关重要。土壤中重要的N ₂ O产生和还原过程是反硝化作用，这表明在低pH值下死亡率降低。尚未建立N ₂ O排放与土壤pH之间的明确关系，因为随着反硝化终产物N ₂ O的相对贡献随着pH的降低而降低。我们的目的是显示土壤pH值对N ₂ O产生和排放的净影响。因此，试验被设计以研究pH的影响对NO ₃ ^-还原，N ₂ ö生产和减少和N ₂在pH值设置为4到7的温育条件下进行生产。此外，还进行了土壤pH和N ₂ O排放的现场测量。在温育，NO ₃ ^-还原和N ₂生产速率随pH和网N增加₂ ö产率为最高，在pH 6. N ₂ O简化为N ₂被停止，直到NO ₃ ^-在低pH值被耗尽，从而导致内置N中的最多₂ O.因此，N ₂ ö：N ₂的生产比例随pH呈指数下降。因此，减少N ₂ O似乎比N ₂更重要O产量解释N ₂ O净生产率。在田间，观察到土壤pH与N ₂ O排放呈负指数关系。因此，土壤pH可以用作研究生态系统中平均N ₂ O排放的预测工具。低pH斑点的出现可以解释N ₂ O发射热点的出现。未来的研究应集中在小规模土壤pH可变性背后的机制以及操纵土壤pH的作用上。