Abstract
Nitrous oxide (N(2)O) is a potent greenhouse gas with intensive emissions from acidic soil. This study explored the impact of the disruption of the microbial balance from microbial inhibitors (streptomycin and cycloheximide) on soil's N(2)O emission and nitrogen (N) dynamics. Under all the conditions examined, biotic processes accounted for 96-98% of total N(2)O emissions. High concentrations of streptomycin (6 and 10 mg g(-1)) reduced N(2)O emissions from 2.24 μg kg(-1) h(-1) to 1.93 μg kg(-1) h(-1) and 2.12 μg kg(-1) h(-1), respectively, whereas lower concentrations (2 and 4.5 mg g(-1)) increased emissions from 2.24 μg kg(-1) h(-1) to 2.95 μg kg(-1) h(-1) and 3.27 μg kg(-1) h(-1), respectively. Lower cycloheximide (2 and 4.5 mg g(-1)) significantly enhanced N(2)O emissions, reaching 9.15 μg kg(-1) h(-1) and 5.68 μg kg(-1) h(-1), respectively, whereas higher dosages (6 mg g(-1) and 10 mg g(-1)) inhibited N(2)O emissions, reducing them to 5.55 μg kg(-1) h(-1) and 4.84 μg kg(-1) h(-1), respectively. Carbon dioxide (CO(2)) emissions generally decreased with increasing inhibitor dosages but significantly increased at 2 mg g(-1) and 4.5 mg g(-1) streptomycin. The inhibitors also altered soil N and carbon (C) dynamics, increasing ammonium (NH(4)(+)-N), dissolved organic nitrogen (DON), and dissolved organic carbon (DOC) levels. Pearson correlation analysis indicated that N(2)O emission was negatively correlated with cycloheximide dosage (R = -0.68, p < 0.001), NH(4)(+)-N (R = -0.31, p < 0.001) and DOC content (R = -0.57, p < 0.05). These findings highlight the consequences of microbial disruption on N(2)O emission and the complex microbial interactions in acidic soils. High concentrations of microbial inhibitors effectively reduce N(2)O emissions by suppressing key microbial groups in nitrification and denitrification. Conversely, lower concentrations may prompt compensatory responses from surviving microorganisms, resulting in increased N(2)O production. Future research should focus on sustainable management strategies to mitigate N(2)O emissions while preserving the soil's microbial community.