Since it is known that nitrous oxide (N₂O) production and consumption pathways are affected by soil pH, optimising the pH of agricultural soils can be an important approach to reduce N₂O emissions. Because liming effects on N₂O reduction had not been studied under ambient atmosphere and typical bulk density of arable soils, we conducted mesoscale incubation experiments with soils from two liming trials to investigate the impact of long-term pH management and fresh liming on N transformations and N₂O production. Soils differed in texture and covered a range of pH levels (3.8–6.7), consisting of non-limed controls, long-term field-limed calcite and dolomite treatments, and freshly limed soils. Both soils were amended with ¹⁵N-labelled potassium nitrate (KNO₃) and incubated with and without incorporated maize litter. Packed soil mesocosms were cycled through four phases of alternating temperatures and soil moistures for at least 40 days. Emissions of N₂O and dinitrogen (N₂) as well as the product ratio of denitrification N₂O/(N₂O + N₂), referred to as N₂Oi were measured with the ¹⁵N gas flux method in N₂-reduced atmosphere. Emissions of N₂O increased in response to typical denitrifying conditions (high moisture and presence of litter). Increased temperature and soil moisture stimulated microbial activity and triggered denitrification as judged from ¹⁵NO₃⁻ pool derived N₂O + N₂ emissions. Fresh liming increased denitrification in the sandy soil up to 3-fold but reduced denitrification in the loamy soil by 80%. N₂Oi decreased throughout the incubation in response to fresh liming from 0.5–0.8 to 0.3–0.4, while field-limed soils had smaller N₂Oi (0.1–0.3) than unlimed controls (0.9) irrespective of incubation conditions. Our study shows that the denitrification response (i.e., N₂O + N₂ production) to liming is soil dependent, whereas liming effects on N₂Oi are consistent for both long- and short-term pH management. This extends previous results from anoxic slurry incubation studies by showing that soil pH management by liming has a good mitigation potential for agricultural N₂O emissions from denitrification under wet conditions outside of cropping season.

由于已知一氧化二氮 (N ₂ O) 的产生和消耗途径受土壤 pH 值的影响，因此优化农业土壤的 pH 值可能是减少 N ₂ O 排放的重要方法。由于尚未在环境大气和耕地土壤的典型容重下研究石灰对 N ₂ O 减少的影响，因此我们对两次石灰试验的土壤进行了中尺度培养实验，以研究长期 pH 管理和新鲜石灰对氮转化的影响和N ₂ O 的产生。土壤质地不同，涵盖一系列 pH 值 (3.8–6.7)，包括未石灰对照、长期田间石灰方解石和白云石处理以及新石灰土壤。两种土壤均用¹⁵ N 标记的硝酸钾 (KNO ₃ )进行改良，并在掺入或不掺入玉米垫料的情况下进行培养。填充的土壤中质环境在温度和土壤湿度交替的四个阶段中循环至少 40 天。采用¹⁵ N气体通量法测定N ₂中N ₂ O和二氮(N ₂ )的排放量以及反硝化产物比N ₂ O/(N ₂ O + N ₂ )，简称N ₂ Oi。 - 气氛减少。 N ₂ O 的排放量随着典型的反硝化条件（高湿度和垃圾的存在）而增加。根据¹⁵ NO ₃ ⁻池产生的 N ₂ O + N ₂排放量判断，温度和土壤湿度的升高刺激了微生物活动并引发了反硝化。新鲜石灰使沙土中的反硝化作用提高了 3 倍，但使壤土中的反硝化作用降低了 80%。在整个培养过程中，由于新鲜石灰的影响，N _{2 Oi 从 0.5-0.8 下降到 0.3-0.4，而无论孵化条件如何，田间施石灰的土壤的 N 2} Oi (0.1-0.3) 都比未施石灰的对照土壤 (0.9) 更小。我们的研究表明，石灰的反硝化反应（即 N ₂ O + N ₂产生）取决于土壤，而石灰对 N ₂ Oi 的影响对于长期和短期 pH 管理都是一致的。这扩展了之前的缺氧浆料孵化研究的结果，表明通过施石灰进行土壤pH值管理对于在种植季节以外的潮湿条件下反硝化造成的农业N _{2 O排放具有良好的缓解潜力。}