亚热带农田和林地大气氮湿沉降与混合沉降比较  

Comparison Between Atmospheric Wet-only and Bulk Nitrogen Depositions at Two Sites in Subtropical China

作　　者：朱潇 王杰飞[1,2,3] 沈健林 肖润林[1,2] 王娟[1,2] 吴金水[1,2] 李勇[1,2] ZHU Xiao;WANG Jie-fei;SHEN Jian -lin;XIAO Run-lin;WANG Juan;WU Jin-shui;LI Yong(Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China;Changsha Research Station for Agricultural ＆ Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China;University of Chinese Academy of Sciences, Beijing 100049, China)

机构地区：[1]中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,长沙410125 [2]中国科学院长沙农业环境观测研究站,长沙410125 [3]中国科学院大学,北京100049

出　　处：《环境科学》2018年第6期2557-2565,共9页Environmental Science

基　　金：国家重点研发计划项目(2016YFD0200307;2017YFD0800104);国家自然科学基金项目(41371303;41771336)

摘　　要：本研究在位于我国亚热带区域的湖南省长沙县金井河流域,设置一个农田监测点和一个林地监测点,开展了完整的2a(2011年3月至2013年2月)大气氮素(N)湿沉降和混合沉降(湿沉降+部分干沉降)的监测,评价两种方法监测的大气氮素沉降的差别,并建立一种采用氮素混合沉降来估算氮素湿沉降的方法.结果表明采样点氮素湿沉降和混合沉降以NH_4^+-N沉降量最高,其中农田点大气氮湿沉降、混合沉降量分别为26.2 kg·(hm^2·a)^(-1)、28.9 kg·(hm^2·a)^(-1),湿沉降、混合沉降NH_4^+-N、NO_3^--N和可溶性有机氮(DON)分别占湿沉降、混合沉降总氮(TN)的49.7%、31.3%、19.0%和48.7%、31.6%、19.7%.林地点大气氮湿沉降、混合沉降量分别为23.6 kg·(hm^2·a)^(-1)、27.8 kg·(hm^2·a)^(-1),湿沉降、混合沉降NH_4^+-N、NO_3^--N和DON分别占湿沉降、混合沉降TN的53.9%、34.8%、11.4%和49.6%、31.6%、18.9%.研究区域降雨量与湿沉降、混合沉降雨水中NH_4^+-N、NO_3^--N和TN浓度均有极显著负相关关系,而与沉降量有显著正相关性.两监测点湿沉降与混合沉降的雨水中N素浓度具有极显著线性相关性(决定系数大于0.82),根据二者之间建立的回归方程,农田点采用混合沉降估算湿沉降中NH_4^+-N、NO_3^--N和TN沉降的系数值分别为0.875、0.774和0.852;林地点相应的系数值分别为0.859、0.783和0.819,该系数值主要与监测点的氮素湿沉降量及大气颗粒态氮的污染水平有关.亚热带区域采用大气氮素混合沉降替代氮素湿沉降,将导致氮素湿沉降被高估10%~18%,利用氮素混合沉降和氮素湿沉降之间的回归方程,可以较好实现采用混合沉降来估算湿沉降.Atmospheric emissions of reactive nitrogen（N） species are at high levels and have caused high N deposition in China in recent years.In this study,atmospheric wet-only and bulk N depositions were monitored simultaneously in a two-year study at an agricultural site（HN） and a forest site（XS） in the Jinjing River catchment in Changsha County,Hunan Province in subtropical China.The differences in concentration and deposition of NH4＋-N,NO3--N,DON,and TN between wet-only and bulk N depositions were compared,and the correlation between wet-only and bulk N depositions was analyzed,with the aim of estimating atmospheric wet N deposition based on bulk N deposition.During the monitoring period,NH4＋-N was the dominant species in both wet-only and bulk deposition at the sampling sites.The average values of total N（TN） depositions for wet-only and bulk depositions at HN were 26.2 and28.9 kg·（hm2·a）（-1）,respectively.The proportions of NH4＋-N,NO3--N,and DON in TN in wet-only deposition were 49.7%,31.3%,and 19.0%,respectively,while the proportions in the bulk deposition were 48.7%,31.6%,and 19.7%,respectively.The average values of TN depositions for wet-only and bulk depositions at XS were 23.6 and 27.8 kg·（hm2·a）（-1）,respectively.The proportions of NH4＋-N,NO3--N,and DON in TN in wet-only deposition were 53.9%,34.78%,and 11.4%,respectively,while they were 49.6%,31.6%,and 18.9%,respectively,for bulk deposition.The concentrations of N species in wet-only and bulk depositions were significantly and negatively correlated with precipitation,while the amount of N deposition was significantly and positively correlated with precipitation.The concentrations of N species in wet-only deposition had a significant linear correlation with those in the bulk deposition at the two sites（R2 〉0.82）.According to the regression equation for wet-only and bulk N deposition atthe monitoring sites,the proportions of NH4＋-N,NO3--N,and TN in wet-only to bulk deposition were 0.875,0.774,and 0.852,respective

关 键 词：大气活性氮 氮沉降 湿沉降 混合沉降 农田生态系统 森林生态系统 

分 类 号：X51[环境科学与工程—环境工程]