Purpose

The contribution of hydroxylamine (NH₂OH) and nitrite (NO₂⁻) to nitric oxide (NO) and nitrous oxide (N₂O) production remains unclear in vegetable production soils.

Materials and methods

Soils collected from six typical greenhouse vegetable fields were incubated for 48 h following amendment with 1 mM NaNO₂, 10 μM NH₂OH, or 1 mM NaNO₂ + 10 μM NH₂OH. The importance of abiotic processes on the NO and N₂O formation from the NH₂OH and NO₂⁻ were studied by irradiating the soil samples with γ-irradiation.

Results and discussion

NO₂⁻ amendment significantly stimulated NO production, while the NH₂OH-dependent NO production was minimal. NH₂OH stimulated more abiotic N₂O production in alkaline soils than in acidic soils (p < 0.05), while NO₂⁻ stimulated more biotic N₂O production in acidic soils than in alkaline soils (p < 0.05). The NH₂OH- and NO₂⁻-dependent sources produced biotic or abiotic N₂O with site preference (SP) values of 27.4–36.5‰, which is similar to those from ammonia-oxidizing archaea (AOA) or ammonia-oxidizing bacteria (AOB) sources (25.1–34.2‰), indicating that abiotic N₂O production were closely linked with biotic NH₃ oxidation. The variability of NO₂⁻+NH₂OH-induced N₂O production can be explained by the soil organic carbon and iron concentrations, whereas NO₂⁻-induced NO production can be explained by the soil pH.

Conclusions

NO₂⁻ addition dominated NO production in all soils. Furthermore, NO₂⁻ addition increased biotic N₂O production in acidic soils, while NH₂OH addition increased abiotic N₂O production in alkaline soils. The presence of NO₂⁻ could significantly stimulate the abiotic conversion of NH₂OH to N₂O in soils with low soil organic carbon and high iron concentrations. Thus, assessing the abundance of NH₂OH and NO₂⁻ could provide crucial information for understanding NO and N₂O production procedures in vegetable soils.

Highlights

• The chemical decomposition of NO₂⁻ dominated NO production in all soils.

• The NH₂OH stimulated abiotic N₂O production in alkaline soils.

• The NO₂⁻ stimulated biotic N₂O production in acidic soils.

• The SP for abiotic NO₂⁻-/NH₂OH-related N₂O were in the same range as AOB/AOA sources.

中文翻译：

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碱性和酸性蔬菜土壤中羟胺和亚硝酸盐对NO和N 2 O产生的贡献

目的

羟胺的贡献（NH ₂ OH）和亚硝酸根（NO ₂ ^- ），以一氧化氮（NO）和一氧化二氮（N ₂ O）的生产仍然在蔬菜生产土壤不清楚。

材料和方法

从六个典型温室菜地收集的土壤中培养48小时如下修正用1mM的NaNO ₂，10μMNH ₂ OH，或1mM的NaNO ₂  + 10μMNH ₂ OH。关于NO和N的非生物过程的重要性₂从NH澳组₂ OH和NO ₂ ^-通过用γ射线照射土壤样品的研究。

结果和讨论

NO ₂ ^-修正案显著刺激NO产生，而NH ₂ OH-依赖NO的产生量极少。NH ₂ OH刺激多种非生物Ñ ₂ ö生产在碱性土壤中比在酸性土壤中（p  <0.05），而NO ₂ ^-刺激的多种生物Ñ ₂ ö生产在酸性土壤比在碱性土壤中（p  <0.05）。所述NH ₂ OH-和NO ₂ ^-依赖性源产生的生物或非生物ñ ₂具有位点偏好（SP）值为27.4–36.5‰的O，类似于来自氨氧化古细菌（AOA）或氨氧化细菌（AOB）来源（25.1–34.2‰）的O ，表明非生物N ₂ O的产生与生物NH ₃氧化密切相关。NO的可变性₂ ^- + NH ₂ OH-诱导Ñ ₂ ö生产可以通过土壤有机碳和铁浓度来说明的，而NO ₂ ^-诱导的NO的产生可通过土壤的pH值进行说明。

结论

NO ₂ ^-除了主导NO生产的所有土壤。此外，NO ₂ ^-除了增加生物Ñ ₂在酸性土壤ø生产，而NH ₂ OH加成增加的非生物Ñ ₂在碱性土壤Ò生产。NO的存在₂ ^-可以显著刺激NH的非生物转化₂ OH至N ₂在具有低土壤有机碳和高铁浓度的土壤O操作。因此，评估NH的丰度₂ OH和NO ₂ ^-可以为理解NO和N提供关键信息₂O在蔬菜土壤中的生产程序。

强调

•NO的化学分解₂ ^-主导NO生产的所有土壤。

•NH ₂ OH刺激了碱性土壤中非生物N ₂ O的产生。

•的NO ₂ ^-刺激的生物ñ ₂在酸性土壤Ò生产。

•非生物NO ₂ ^-- / NH ₂ OH相关N ₂ O的SP与AOB / AOA来源的SP处于相同范围内。