黄河三角洲滨海地区植物生长季大气氮沉降动态

Atmospheric Nitrogen Deposition During Growing Season in Coastal Zone of the Yellow River Delta

利用SCJ-302型降水降尘自动采样器在植物生长季对黄河三角洲滨海湿地的大气氮沉降进行监测,对沉降物中水溶性离子、干、湿沉降氮输入量、铵态氮和硝态氮在总沉降量中的贡献率及月变化动态等分析表明:黄河三角洲植物生长季,大气干、湿沉降中SO42-和NO3-占阴离子总量的92%以上,和Na+和Ca2+占阳离子总量的80%以上,总N沉降量约为2 264.24 mg/m2,且69%集中在降雨量较丰沛的6~8月。其中干沉降氮贡献率约为32.02%,主要集中在春季。N的湿沉降量与降雨量呈显著正线性相关(R2=0.82),在降雨量丰沛的8月,达到最大值675.64 mg/m2。该地区大气干沉降的氮素形态以硝态氮为主,约占氮素输入量的57.21%,湿沉降中以铵态氮为主,约占氮素输入量的56.51%。植物生长季中,大气沉降中的硝态氮与铵态氮含量对表层10 cm土壤的月平均贡献率分别为约31.38%和20.50%,可见大气氮沉降是黄河三角洲滨海区域土壤主要氮素来源之一。

Wet and dry atmospheric depositions were monitored in plant growing season in coastal wetland of Yellow River Delta using SCJ-302 model automatic sampling equipment. The water-soluble ions, wet and dry atmospheric N depositions, monthly variation and the proportion of NH4+-N and NO3--N in total nitrogen deposition were analyzed. The results showed that SO42-and NO3-accounted for more than 92% of the anion numbers, Na+and Ca2+accounted for more than 80% of the cation numbers, respectively, in wet and dry atmospheric depositions in growing season in the Yellow River Delta. The total atmospheric nitrogen deposition was about 2 264.24 mg/m2, and 69% of it occurred from June to August in which the precipitation was abundant. In the total atmospheric nitrogen deposition, dry atmospheric nitrogen deposition accounted for about 32.02%,and it was high in spring. The significant positive relationship between wet nitrogen deposition and precipitation was observed in the study(R2=0.82). The wet atmospheric nitrogen deposition reached peak value in August(675.64 mg/m2). In the studied area, the predominant nitrogen in dry atmospheric deposition was NO3--N with about 57.21% of total dry atmospheric nitrogen deposition, while the predominant nitrogen in wet atmospheric deposition was NH4+-N with about 56.51% of total wet atmospheric nitrogen deposition. In plant growing season, the average monthly attribution rate of atmospheric deposition of NO3--N and NH4+-N were about31.38% and 20.50% for the contents of NO3--N and NH4+-N in 10 cm soil layer, respectively. Therefore, the atmospheric nitrogen was one of main sources for soil nitrogen in coastal zone of Yellow River Delta.