Long‐term fertilization regimes change soil nitrification potential by impacting active autotrophic ammonia oxidizers and nitrite oxidizers as assessed by DNA stable isotope probing

Abstract

Summary Chemoautotrophic ammonia‐oxidizers and nitrite‐oxidizers are responsible for a significant amount of soil nitrate production. The identity and composition of these active nitrifiers in soils under different long‐term fertilization regimes remain largely under‐investigated. Based on that soil nitrification potential significantly decreased in soils with chemical fertilization (CF) and increased in soils with organic fertilization (OF), a microcosm experiment with DNA stable isotope probing was further conducted to clarify the active nitrifiers. Both ammonia‐oxidizing archaea (AOA) and bacteria (AOB) were found to actively respond to urea addition in soils with OF and no fertilizer (CK), whereas only AOB were detected in soils with CF. Around 98% of active AOB were Nitrosospira cluster 3a.1 in all tested soils, and more than 90% of active AOA were Nitrososphaera subcluster 1.1 in unfertilized and organically fertilized soils. Nitrite oxidation was performed only by Nitrospira‐like bacteria in all soils. The relative abundances of Nitrospira lineage I and VI were 32% and 61%, respectively, in unfertilized soils, and that of Nitrospira lineage II was 97% in fertilized soils, indicating long‐term fertilization shifted the composition of active Nitrospira‐like bacteria in response to urea. This finding indicates that different fertilizer regimes impact the composition of active nitrifiers, thus, impacting soil nitrification potential.

Nitrification is a minor source of nitrous oxide (N2O) in an agricultural landscape and declines with increasing management intensity

“…AOB, ammonia-oxidizing bacteria; N 2 O, nitrous oxide [Colour figure can be viewed at wileyonlinelibrary.com] in turn, could affect relative N 2 O production. Upon fertilization, nitrifier community composition appears to favor AOB and in particular Nitrosospira spp., with no similar consistent changes in AOA yet identified (Bertagnolli et al, 2016;Kong et al, 2019;Phillips et al, 2000;Wu et al, 2011;Xue et al, 2016). Soil Nitrosospira spp.…”

Oxytetracycline, copper, and zinc effects on nitrification processes and microbial activity in two soil types

“…The first step involving conversion of ammonia to nitrite is often assumed to be rate limiting and performed by ammonia‐oxidizing bacteria (AOB) and ammonia‐oxidizing archaea (AOA; van Kessel et al., 2015). Organic fertilization involving manure application affects microbial functional diversity by mediating the availability of soil inorganic N and bioavailable organic matter, thereby affecting the nitrification process in agricultural soils (Kong et al., 2019). In addition to direct effects, organic fertilization could indirectly regulate nitrification processes through the accumulation of antibiotics and heavy metals in manures.…”

Soil Amendments Alter Ammonia-Oxidizing Archaea and Bacteria Communities in Rain-Fed Maize Field in Semi-Arid Loess Plateau

“…b (Nitrososphaera cluster) and are normally found in soils [62]. In slightly neutral and calcareous soils, the dominant active AOA is mineral N, which is functionally degraded after long-term fertilization [12]. The high proportion of mineral N fertilizer (CF) and control amendments (NA) found in our study area may have influenced Nitrososphaera group I.1.…”

“…Diversity and abundance of AOA during the nitrification process showed vital functions in soils with low ammonia rate, high acidity, and low oxygen properties [5,10], but AOB shows dominance in alkaline soils during the nitrification process [9,11]. In comparison, organic N in the form of cow manure and corn stalk support AOA productivity dramatically [1,6], while in neutral and calcareous soils treated with high NH 4 + -N and NO 3 − -N fertilizer applications, AOB is a key contributor in nitrification [8,9,12]. Therefore, to revert this defect, cow manure with urea and corn stalk is essential to help augment soil microbial abundance and richness [1,13,14].…”