Impact of dimethylpyrazole-based nitrification inhibitors on soil-borne bacteria
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Date
2021-06-15Author
Corrochano Monsalve, Mario
González Murua, María del Carmen Begoña
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Science of the Total Environment 792 : (2021) // Article ID 148374
Abstract
[EN] Nitrogen (N) input from fertilizers modifies the properties of agricultural soils as well as bacterial community
diversity, composition and relationships. This can lead to negative impacts such as the deterioration of
system multifunctionality, whose maintenance is critical to normal nutrient cycling. Synthetic nitrification
inhibitors (NIs) can be combined with fertilizers to improve the efficiency of N use by reducing N losses.
However, analysis of their effects on non-target bacteria are scarce. This study aimed to analyze the effect
of applying the NIs DMPP and DMPSA on the whole bacterial community. Through 16S rRNA amplicon
sequencing we determined the differences between samples in terms of microbial diversity, composition
and co-occurrence networks.
The application ofDMPP and DMPSA exerted little impact on the abundance of the dominant phyla. Nevertheless,
several significant shifts were detected in bacterial diversity, co-occurrence networks, and the abundance of particular
taxa, where soil water content played a key role. For instance, the application of NIs intensified the negative
impact of N fertilization on bacterial diversity under high water-filled pore spaces (WFPS) (>64%), reducing
community diversity, whereas alpha-diversity was not affected at low WFPS (<55%). Interestingly, despite NIs
are known to inhibit ammonia monooxygenase (AMO) enzyme, both NIs almost exclusively inhibited
Nitrosomonas genera among AMO holding nitrifiers. Thus, Nitrosomonas showed abundance reductions of up to
47% (DMPP) and 66% (DMPSA). Nonetheless, non-target bacterial abundances also shifted with NI application.
Notably,DMPSA application partially alleviated the negative effect of fertilization on soil multifunctionality. A remarkable
increase in populations related to system multifunctionality, such as Armatimonadetes (up to+21%), Cyanobacteria (up to +30%) and Fibrobacteres (up to+25%) was observed when DMPSA was applied. NI application
substantially influenced microbial associations by decreasing the complexity of co-occurrence networks,
decreasing the total edges and node connectivity, and increasing path distances.