Asymmetries among soil fungicide residues, nitrous oxide emissions and microbiomes regulated by nitrification inhibitor at different moistures

Carbendazim residue has been widely concerned, and nitrous oxide (N 2 O) is one of the dominant greenhouse gases. Microbial metabolisms are fundamental processes of removing organic pollutant and producing N 2 O. Nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) can change soil abiotic properties and microbial communities and simultaneously affect carbendazim degradation and N 2 O emission. In this study, the comprehensive linkages among carbendazim residue, N 2 O emission and microbial community after the DMPP application were quantified under different soil moistures. Under 90% WHC, the DMPP application significantly reduced carbendazim residue by 54.82% and reduced soil N 2 O emission by 98.68%. The carbendazim residue was negatively related to soil ammonium nitrogen (NH 4 + -N), urease activity, and ratios of Bacteroidetes , Thaumarchaeota and Nitrospirae under 90% WHC, and the N 2 O emission was negatively related to NH 4 + -N content and relative abundance of Acidobacteria under the 60% WHC condition. In the whole (60% and 90% WHC together), the carbendazim residue was negatively related to the abundances of nrf A (correlation coefficient = -0.623) and nrf H (correlation coefficient = -0.468) genes. The hao gene was negatively related to the carbendazim residue but was positively related to the N 2 O emission rate. The DMPP application had the promising potential to simultaneously reduce ecological risks of fungicide residue and N 2 O emission via altering soil abiotic properties, microbial activities and communities and functional genes. Environmental Implication: Carbendazim was a high -efficiency fungicide that was widely used in agricultural production. Nitrous oxide (N 2 O) is the third most important greenhouse gas responsible for global warming. The 3, 4-dimethylpyrazole phosphate (DMPP) is an effective nitrification inhibitor widely used in agricultural production. This study indicated that the DMPP application reduced soil carbendazim residues and N 2 O emission. The asymmetric linkages among the carbendazim residue, N 2 O emission, microbial community and functional gene abundance were regulated by the DMPP application and soil moisture. The results could broaden our horizons on the utilizations DMPP in decreasing fungicide risks and N 2 O emission.