BTEX are known as a type of volatile organic compounds (VOCs), which involve in atmospheric photochemical process and pose threats to human health and environment. Soil can act as both source and sink for BTEX. Increasing nitrogen deposition may influence soil ecological processes leading to changes in soil BTEX fluxes. Although nitrogen deposition has received much attention, the research on soil BTEX fluxes impacted by nitrogen deposition is still scarce. In this study, employing the static-chamber coupled with preconcentrator-GC-MS techniques, the responses of soil BTEX fluxes to simulated elevated nitrogen deposition were studied in two dominated forests, namely, pine forest (PF) and monsoon evergreen broadleaf forest (BF) in Dinghushan. The results showed that PF soil acted as sink for BTEX in the controlled sites, with the maximum uptake rate of (-51.52±10.94) pmol·m-2·s-1 for ethyl benzene. BTEX uptake rates decreased with low nitrogen additions and the soil function changed from “sink” to “source” with medium nitrogen additions in PF. In BF, meanwhile, soil acted as source for BTEX in controlled sites, with the maximum emission rate of (7.11±0.12) pmol·m-2·s-1for toluene. BTEX emission rates decreased, or the soil changed the function from “source” to “sink” after the nitrogen additions in BF, with the significant difference in low and high nitrogen addition sites from those in controlled sites. In addition, significantly high correlation coefficients were observed between toluene and ethyl benzene, xylene in PF soil as well as between benzene and toluene, xylene in BF soil with nitrogen treated. On the basis of measurements every 3 h each day for controlled and high nitrogen addition sites in BF, no clear diurnal variations were found for BTEX fluxes. The highest emission rates appeared at 7:00 in both sites and the highest uptake rates appeared at 19:00 and 13:00 in the controlled site and high nitrogen addition site, respectively. Soil CO2 emission rates (29.46±3.27) mg·m-2·h-1 in BF were significantly higher than those in PF in controlled sites (11.02±0.96) mg·m-2·h-1, and the rates in all the nitrogen addition sites increased compared with those in the controlled sites in both forests. Soil BTEX fluxes showed no significant correlation with soil temperature, air temperature or CO2 emission rates, but o-xylene and ethyl benzene fluxes showed significant correlation with soil water content.%苯系物（BTEX）是一类重要的挥发性有机化合物（VOCs），能参与大气光化学反应，并对人体健康有重要影响。土壤能释放或吸收BTEX，氮沉降会影响土壤生态过程，从而可能影响土壤BTEX通量。有关森林土壤BTEX通量对氮沉降响应的研究十分有限。运用静态箱采样、利用大气预浓缩仪-GC-MS研究了鼎湖山两种典型森林——马尾松林（Pine forest, PF）和季风常绿阔叶林（Monsoon evergreen broadleaf forest, BF）土壤BTEX通量对模拟氮沉降增加的响应。结果表明：自然氮沉降条件下，PF土壤吸收BTEX，乙苯吸收速率最大(-51.52±10.94) pmol·m-2·s-1，低氮抑制了PF土壤对BTEX的吸收，中氮主要使土壤由“汇”变为“源”；BF土壤释放BTEX，甲苯释放速率最高(7.11±0.12) pmol·m-2·s-1，施氮降低了BF土壤BTEX释放量或使土壤由“源”变“汇”，且低氮和高氮的影响效果更显著。施氮条件下，PF 土壤甲苯与乙苯、间/对二甲苯、邻二甲苯通量显著相关，BF土壤苯与甲苯、间/对二甲苯、邻二甲苯显著相关。土壤BTEX通量无明显日变化规律，对照和高氮样地最大释放均出现在7：00，最大吸收出现在19：00（对照样地）和13：00（高氮样地）。自然氮沉降条件下，BF土壤CO2通量(29.46±3.27) mg·m-2·h-1显著高于PF土壤(11.02±0.96) mg·m-2·h-1，两个水平氮处理均促进了两种林型土壤CO2的释放。土壤BTEX通量与土壤温度、大气温度和CO2浓度无显著相关性；邻二甲苯和乙苯通量与土壤湿度呈显著相关。
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