Codenitrification is a reactive nitrogen (N) removal pathway producing hybrid dinitrogen (N₂) by combining nitrite (NO₂^–) and a partner-N substrate. Abiotic codenitrification also produces hybrid N₂ through nitrosation of organic N by NO₂^–, but it is poorly constrained in soil N cycles. We determined the importance of abiotic codenitrification in soils and examined factors controlling abiotic codenitrification using live soils, sterile soils, and sterile solutions. Abiotic codenitrification in sterile soils ranged from 0.12 ± 0.001 to 0.60 ± 0.08 nmoles ²⁹N₂-N g^–1 day^–1, which accounts for 2.3 to 8.2% of total N₂ production measured in live soils. Increased abiotic N₂ production was observed in soils with the addition of an organic N partner (glutamine). Consistent with previous work, higher rates were observed in lower-pH soils, but the highest rate was found in the soil with the highest carbon:nitrogen (C:N) ratio. We further investigated a range of organic N partners and the influence of concentration and pH on abiotic codenitrification in solution. Similar to sterile soil incubations, abiotic ²⁹N₂ production was negatively correlated with increasing pH in solution. Greater rates of abiotic ²⁹N₂ production were measured as the substrate concentration increased and pH decreased. Solution experiments also showed that addition of organic N partners increased abiotic codenitrification rates, which are positively correlated with the C:N ratios of organic N partners. This is the first study demonstrating the importance of N removal through abiotic codenitrification in acidic soils and the C:N ratio of organic N partners as a controlling factor in abiotic codenitrification.

中文翻译：

---

确定控制非生物共硝化的化学因素

Codenitrification是活性氮（N）移除路径中产生杂种二氮（N ₂通过组合亚硝酸盐（NO）₂ ^- ）和一伙伴-N衬底。非生物codenitrification也产生杂合N- ₂通过的有机氮亚硝化由NO ₂ ^{- ，}但它是在土壤N个周期约束较差。我们确定了非生物共硝化在土壤中的重要性，并研究了使用活性土壤，无菌土壤和无菌溶液控制非生物共硝化的因素。无菌土壤中的非生物共氮化作用范围从0.12±0.001到0.60±0.08 nmoles ²⁹ N ₂ -N g ^–1天^–1，占活土壤中N ₂总产量的2.3％至8.2％。在土壤中添加有机氮伙伴（谷氨酰胺）可以增加非生物氮_2的产生。与以前的工作一致，在pH值较低的土壤中观察到了较高的比率，但在碳/氮（C：N）比最高的土壤中发现了最高的比率。我们进一步研究了一系列有机氮伙伴以及浓度和pH对溶液中非生物共硝化的影响。与无菌土壤培养相似，非生物²⁹ N _2的产生与溶液中pH的增加呈负相关。非生物性²⁹ N _2的比率更高随着底物浓度的增加和pH值的降低来测量产量。溶液实验还表明，添加有机氮伙伴增加了非生物共硝化率，这与有机氮伙伴的C：N比正相关。这是第一项研究，证明了在酸性土壤中通过非生物共硝化去除氮的重要性以及有机N伙伴的C：N比作为非生物共硝化的控制因素。