Effects of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on the activity and diversity of the soil microbial community under contrasting soil pH

Impacts of urea and 3,4-dimethylpyrazole phosphate on nitrification, targeted ammonia oxidizers, non-targeted nitrite oxidizers, and bacteria in two contrasting soils

“…This suggests that the effects of short-term urea on bacterial αdiversity depends on soil type. We found that DMPP had no significant effects on the α-diversity indices of bacteria when compared to the urea-only treatment, which concurs with a recent study (Bachtsevani et al, 2021). Our results did, however, show that urea significantly altered the bacterial community structure-the relative abundance of bacterial main phyla increased or decreased in both soils, which contradicts a previous study (Luchibia et al, 2020).…”

“…We analyzed the effects of urea and urea with DMPP on nitrification in two contrasting soils. DMPP was more effective at impeding net nitrification rates in the acidic soil than in the neutral soil (Table 2), which was inconsistent with some previous studies (Shi et al, 2016a,b) but supports a more recent study (Bachtsevani et al, 2021). One possible explanation is that DMPP, as a type of heterocylic compound, can be adsorbed onto soil organic matter (McCarty and Bremner, 1989), thus diminishing the efficacy of DMPP hindering nitrification (Barth et al, 2008).…”

“…The influences of DMPP on nitrite oxidizers are still unclear. A recent study reported that DMPP inhibited the growth of Nitrobacter-like NOB but not Nitrospira-like NOB in acidic and alkaline soils at a high dose rate (Bachtsevani et al, 2021). The inhibitory effects of DMPP at the recommended dose rate on the growth of Nitrobacter-and Nitrospira-like NOB in the tested soils are not significant, probably because there is no target for DMPP in NOB.…”

“…For example, Luchibia et al (2020) revealed that DMPP application did not alter the bacterial community composition based on 16S rRNA gene sequencing in a grassland soil. However, Bachtsevani et al (2021) found that DMPP had significant effects on bacterial community composition in two different types of cropland soils. To fully understand the impacts of DMPP on soil biological functions, it is necessary to explore its non-targeted effects on soil microbial communities, including NOB and bacteria-not just on targeted ammonia oxidizers.…”

“…For example, a recent study showed that DMPP specifically and effectively inhibited AOB growth, while having no effect on AOA in three types of soils (Yin et al, 2021). Others reported that DMPP obviously reduced the abundance and activity of both AOA and AOB (Florio et al, 2014;Bachtsevani et al, 2021). In addition, recent studies suggest that DMPP significantly inhibited the growth of comammox in various types of soils (Li et al, 2019(Li et al, , 2020.…”