Asymmetries among soil fungicide residues, nitrous oxide emissions and microbiomes regulated by nitrification inhibitor at different moistures
Carbendazim is a widely used fungicide but causes widespread residues in soils and crops, and nitrous oxide (N2O) is one of the dominant greenhouse gases. The 3,4-dimethylpyrazole phosphate (DMPP), a nitrification inhibitor, might simultaneously affect fungicide dissipation and N2O emission. In this study, we applied the DMPP to agricultural soils contaminated with carbendazim under 60% and 90% soil water holding capacity (WHC) to quantify the carbendazim residues and N2O emission at various sampling times. The comprehensive linkages among N2O emission, microbial activities, community diversities, compositions and functional genes were quantified. Under 90% WHC, the DMPP applications significantly reduced carbendazim residues by 23.62% and 54.82% on days 10 and 20, respectively. The DMPP application also reduced soil N2O emission by 17.69% under 60% WHC and 98.68% under 90% WHC. The carbendazim residue was negatively related to soil NH4+-N, urease activity, and ratio of Bacteroidetes, Thaumarchaeota and Nitrospirae under 90% WHC, and the N2O emission rate was negatively related to NH4+-N content and relative abundance of Acidobacteria under the 60% WHC condition. In the whole (60% and 90% WHC together), the hao gene was negatively related to the carbendazim residue but positively related to the N2O emission rate. The asymmetric linkages among the carbendazim residue, N2O emission, microbial community and functional gene abundance were regulated by the DMPP application and soil moisture. The DMPP application had the promising potential to simultaneously reduce ecological risks of fungicide residues and N2O emissions via altering soil abiotic properties, microbial activity, and community and functional genes.
National Natural Science Foundation of China