南充市主城区大气氮湿沉降特征研究

Research on the Characteristics of Atmospheric Wet Nitrogen Deposition in the Urban Areas of Nanchong City

为了进一步了解南充主城区大气氮沉降的变化特征,采用降水采集法对南充市全年大气各形态氮浓度及通量进行了动态分析。结果表明:①各形态氮具有明显的变化特征,TDN、DON、NH_(4)^(+)-N、DIN的季节浓度变化表现为春冬高、夏秋低的趋势,NO_(3)^(-)-N的季节浓度变化表现为春夏高、秋冬低的趋势;②TDN、DON和DIN的沉降通量表现为夏秋高、春冬低的季节变化趋势,NO_(3)^(-)-N沉降通量表现为春夏高、秋冬低的变化趋势,NH_(4)^(+)-N的沉降浓度表现为夏秋高、春冬低的变化趋势;③在空间差异上,4个观测点的沉降浓度没有明显差异。综上所述,南充市湿氮沉降显著,且以可溶性有机氮为主,有一定的增肥作用,这可能对区域林业和农业发展有一定的促进作用。

In order to further understand the change characteristics of atmospheric nitrogen deposition in the main urban areas of Nanchong City,the precipitation collection method was used to observe the atmospheric nitrogen wet deposition from March 2019 to February 2020 in Nanchong City,and the total soluble nitrogen(TDN)and soluble inorganic nitrogen(DIN)in precipitation were analyzed.The dynamics of the concentration and sedimentation flux of ammonium nitrogen(NH_(4)^(+)-N),nitrate nitrogen(NH_(3)^(-)-N)and soluble organic nitrogen(DON)were analyzed.The results showed as follows:①the seasonal concentrations of TDN,DON,NH_(4)^(+)-N and DIN showed a trend of higher spring and winter and lower summer and autumn,while the seasonal concentrations of NH_(3)^(-)-N showed a trend of higher spring and summer and lower autumn and winter;②the sedimentation fluxes of TDN,DON and DIN showed a seasonal variation trend of high in summer and autumn and low in spring and winter;the NH_(3)^(-)-N sedimentation fluxes showed a trend of high in spring and summer and low in autumn and winter;and the NH_(4)^(+)-N sedimentation concentration showed a trend of high in summer and autumn and low in spring and winter;③in terms of spatial differences,there is no significant difference in sedimentation concentration among the four observation points.In summary,the precipitation of wet nitrogen in Nanchong City is significant,and soluble organic nitrogen is the main factor,which has a certain effect of increasing fertilizer and may promote the development of regional forestry and agriculture.