Global gross nitrification rates are dominantly driven by soil carbon-to-nitrogen stoichiometry and total nitrogen
Global gross nitrification rates are dominantly driven by soil carbon-to-nitrogen stoichiometry and total nitrogen
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DOI：
10.1111/gcb.15883
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发表时间：
2021-09-23
影响因子：
11.6
通讯作者：
Mueller, Christoph
中科院分区：
文献类型：
--
作者：
Elrys, Ahmed S.;Wang, Jing;Mueller, Christoph
土壤总硝化作用（GN）是全球氮循环中的一个关键过程，通过微生物氧化铵态氮或有机氮形成硝态氮，既能增加植物对氮的有效性，又能增加氧化亚氮的排放。土壤GN被认为主要受土壤特性和气候的控制，但考虑到气候，土壤特性，包括微生物特性，以及它们之间的相互作用，以更好地了解全球GN率的直接和间接控制因素的综合分析是缺乏的。使用基于来自330个N-15标记研究的901个观察结果的全球荟萃分析，我们表明GN在生态系统类型之间存在显着差异，在农田中发现的比例最高，与刺激硝化细菌活动的较高pH值相关。自养和异养硝化分别占全球GN的63%和37%。土壤GN随土壤全氮、微生物生物量和pH值的增加而显著增加，随土壤碳氮比的增加而显著降低。结构方程模型分析表明，土壤氮素营养主要受C：N和土壤全N的控制。微生物生物量和pH值也是控制GN的重要因素，其作用相似。降水和温度通过改变C：N和/或土壤全N来影响GN。土壤全氮和温度驱动异养硝化，而C：N和pH驱动自养硝化。此外，GN与一氧化二氮和二氧化碳排放呈正相关。这种综合表明，土壤C：N，土壤全N，微生物种群大小，和/或土壤pH值的变化，由于人类活动可能会影响GN，这将影响硝酸盐积累和气体排放的土壤在全球气候和土地利用变化。
Soil gross nitrification (GN) is a critical process in the global nitrogen (N) cycle that results in the formation of nitrate through microbial oxidation of ammonium or organic N, and can both increase N availability to plants and nitrous oxide emissions. Soil GN is thought to be mainly controlled by soil characteristics and the climate, but a comprehensive analysis taking into account the climate, soil characteristics, including microbial characteristics, and their interactions to better understand the direct and indirect controlling factors of GN rates globally is lacking. Using a global meta-analysis based on 901 observations from 330 N-15-labeled studies, we show that GN differs significantly among ecosystem types, with the highest rates found in croplands, in association with higher pH which stimulates nitrifying bacteria activities. Autotrophic and heterotrophic nitrifications contribute 63% and 37%, respectively, to global GN. Soil GN increases significantly with soil total N, microbial biomass, and soil pH, but decreases significantly with soil carbon (C) to N ratio (C:N). Structural equation modeling suggested that GN is mainly controlled by C:N and soil total N. Microbial biomass and pH are also important factors controlling GN and their effects are similar. Precipitation and temperature affect GN by altering C:N and/or soil total N. Soil total N and temperature drive heterotrophic nitrification, whereas C:N and pH drive autotrophic nitrification. Moreover, GN is positively related to nitrous oxide and carbon dioxide emissions. This synthesis suggests that changes in soil C:N, soil total N, microbial population size, and/or soil pH due to anthropogenic activities may influence GN, which will affect nitrate accumulation and gaseous emissions of soils under global climate and land-use changes.