Nitrification acidifies soil, and the produced H are neutralized by inorganic carbon (C) in soil leading to irreversible CO emissions. CO released by nitrogen (N) fertilizer-induced acidification is partitioned between solid (CaCO re-precipitation), liquid (dissolved HCO and CO) and gaseous (CO) phases. Therefore, quantifying the effects of N fertilization on CO emissions from soil inorganic C is an enormous challenge. C-labeled CaCO was used as a model inorganic C to trace the released CO caused by acidification by five fertilizers: chicken manure, urea, KNO, NHNO, and (NH)SO added at three N rates. Cropland soil was homogenously mixed with CaCO powder and fertilizers, and the emitted CO was trapped in NaOH solution to determine total CO and CO efflux originated from inorganic C. Fertilization, particularly ammonium-based fertilizers ((NH)SO, NHNO), strongly decreased soil pH by 0.35 units over 40 days. All fertilizers except KNO increased total CO emissions by 21%–490% compared to the unfertilized control soil. The fertilization effects on cumulative CO emission induced by CaCO neutralization, corresponded to acidification and decreased in the order (NH)SO > NHNO > urea > KNO > chicken manure. Ammonium-based fertilizers induced the strongest CO emissions originated from inorganic C, emitting 1.6–4.5 times more CO than non-fertilized soils during the first nine days. The total CO emissions from SIC were proportional to the fertilizer dose applied. Therefore, we conclude that both the choice of N fertilizers and their application rates need to be considered to control CO emissions originated from inorganic C. The soil inorganic C losses should be prevented not only because of their irreversible contribution to atmospheric CO, but also to safeguard ecosystem services of CaCO, such as organic matter preservation, soil structure stabilization, and C sequestration.

中文翻译：

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硝化引起的酸度控制土壤碳酸盐的二氧化碳排放

硝化作用使土壤酸化，产生的 H 被土壤中的无机碳 (C) 中和，导致不可逆的 CO 排放。氮 (N) 肥引起的酸化释放的 CO 分为固相（CaCO 再沉淀）、液相（溶解的 HCO 和 CO）和气相 (CO)。因此，量化施氮肥对土壤无机碳二氧化碳排放的影响是一个巨大的挑战。使用 C 标记的 CaCO3 作为无机 C 模型，追踪五种肥料（鸡粪、尿素、KNO、NHNO 和 (NH)SO 以三种氮添加量添加）酸化引起的 CO 释放。将农田土壤与 CaCO 粉末和肥料均匀混合，并将排放的 CO 捕获在 NaOH 溶液中，以确定源自无机 C 的总 CO 和 CO 流出量。施肥，特别是铵基肥料（(NH)SO、NHNO）大幅下降40 天内土壤 pH 值降低 0.35 个单位。与未施肥的对照土壤相比，除硝酸钾之外的所有肥料都增加了 21%–490% 的二氧化碳总排放量。施肥对CaCO中和引起的累积CO排放的影响与酸化相对应，并按(NH)SO > NHNO > 尿素 > KNO > 鸡粪的顺序降低。铵基肥料引起的二氧化碳排放量最强，源自无机碳，在前 9 天排放的二氧化碳量是未施肥土壤的 1.6-4.5 倍。 SIC 的 CO 排放总量与施肥剂量成正比。因此，我们的结论是，需要考虑氮肥的选择及其施用量来控制源自无机碳的二氧化碳排放。应防止土壤无机碳损失，不仅因为它们对大气二氧化碳的不可逆贡献，而且还因为它们对大气二氧化碳的贡献。保护 CaCO 的生态系统服务，例如有机质保存、土壤结构稳定和碳封存。