Nitrification inhibitors mitigate earthworm-induced N2O emission—a mesocosm study

Abstract

In this study, the soils with or without earthworms (Eisenia fetida) were treated with one of the two following nitrification inhibitors (NIs): dicyandiamide (DCD) or 3,4-dimethylpyrazole phosphate (DMPP); then, the soils were incubated for 90 days in laboratory mesocosms. The cumulative nitrous oxide (N 2 O) emission increased from 74.08 μg N 2 O-N kg −1 in the control to 384.69 μg N 2 O-N kg −1 in the earthworm-treated soil. The addition of NI decreased the cumulative N 2 O emissions from soils by 67.1 % in the DCD treatment and 73.4 % in the DMPP treatment without earthworms and by 79.0 and 81.0 % with earthworms, respectively. After 90 days, the richness of nirK gene in the soil decreased in both DCD and DMPP treatments compared with control, and the abundance of denitrifying bacteria in the gut of earthworm declined to less than 1/1000 or 1/100 of those without NIs. At 7 and 90 days, N 2 O production by denitrification in earthworm gut homogenates in both NI treatments decreased compared to those without NIs. Therefore, this study provided a fundamental evidence for that the application of NImitigated N 2 O emission induced by earthworm (E. fetida).

Earthworms enhance the inhibition efficiency of 3,4-dimethylpyrazole phosphate on soil nitrification by altering soil AOB communities and gut denitrifier communities

“…1d). These could be further supported by a previous study that observed a similar effect of DMPP on soils amended with E. fetida (epigeic earthworm) (Wang et al 2015). However, the fluctuation ranges of 1 3 the earthworm-induced N 2 O emissions in our study were much greater than theirs.…”

Inhibitory Effects of 3,4-Dimethylpyrazole Phosphate on CH4 and N2O Emissions in Paddy Fields of Subtropical China

“…With 0.42% nitrogen fertilizer as an active ingredient (3 mg kg −1 soil DMPP with 715 mg N kg −1 soil), DMPP was observed to slow oxidation considerably, and reduced N 2 O emissions by 83–95% under both 40% and 60% WFPS (water-filled porespace) [ 18 ]. The addition of 1% DMPP decreased the cumulative N 2 O emissions of soils by 73.4% [ 52 ]. DMPP with mineral fertilizers, and at a low concentration of 1%, specifically inhibited nitration and stabilized for several weeks [ 13 ].…”

Response of ammonia oxidizers and denitrifiers to repeated applications of a nitrification inhibitor and a urease inhibitor in two pasture soils

“…Several studies have reported that the application of nitrification inhibitors reduced denitrification-produced N 2 O through decreasing the functional gene abundances of denitrifiers (Dong et al 2013a;Kou et al 2015;Wang et al 2015). Further research is highly desirable to relate the changes in microbial functional genes abundance to process rates.…”