Evidences of N2O Emissions in Chloropicrin-Fumigated Soil

The mechanism of N 2 O production following chloropicrin (CP) fumigation was investigated in this study. Our results showed that CP fumigation increased N 2 O production from 23 to 25 times in comparison with the control and significantly decreased the abundance of 16S rRNA and N-cycling functional genes. CP also decreased the soil bacterial diversity and caused a shift in the community composition. The N 2 O emissions in fumigated soil were significantly correlated with soil environmental factors (NH 4 +, dissolved amino acid, microbial biomass nitrogen, and NO 3 – ) but were not correlated with the abundance of functional genes. Metatranscriptomes and dual-label 15 N– 18 O isotope analysis revealed that CP fumigation inhibited the expression of gene families involved in N 2 O production and sink processes and shifted the main pathway of N 2 O production from nitrification to denitrification. These results provided useful information for environmental safety assessments of CP in China, to improve our understanding of the N-cycling pathways in fumigated soils.