滇池北岸典型农区韭菜田大气氮湿沉降与氮挥发研究

中国环境科学 2010,30(10)：1309~1315 China Environmental Science 滇池北岸典型农区韭菜田大气氮湿沉降与氮挥发研究

陆海燕1,2,胡正义1,2*,张瑞杰1,殷小锋1,逢玉万1,吴永红1 (1.中国科学院南京土壤研究所,土壤与农业可持续发展国家重点实验室,江苏南京 210008；2.中国科学院研究生院,资源与环境学院,北京 100049)

摘要：选择滇池北岸大清河下游典型农区韭菜田为对象,对雨水进行化学分析,研究了2007年大气氮湿沉降通量及其动态变化,并通过田间试验观测了地表(韭菜地土壤、韭菜废弃物原位腐解、沟渠污水)的氨氮挥发.结果表明,全年大气湿沉降氮(以N计)7.1kg/hm2,其中雨季(4~9月份)占89%.韭菜一次基施尿素(以N计)276kg/hm2,35d累计氨挥发占施氮量的32%,其中前9d氨挥发占总氨挥发96%.韭菜残体腐解21d 累计氮挥发占植株氮23%.含氮7~51mg/L的污水(其中氨氮2.7~25.8mg/L)露天放置12d,水体总氮的27%~38%挥发进入大气.可见,韭菜田氮挥发是该地大气氮重要来源之一.

关键词：氮；大气氮沉降；氨挥发；面源污水；农业固废处置；滇池

中图分类号：X511 文献标识码：A 文章编号：1000-6923(2010)10-1309-07

Atmospheric nitrogen wet deposition and nitrogen volatilization in Chinese chive planting field of a typical agricultural area at northern bank of Dianchi Lake. LU Hai-yan1,2, HU Zheng-yi1,2*, ZHANG Rui-jie1, YIN Xiao-Feng1, PANG Yu-wan1, Wu Yong-hong1 (1.State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China；2.College of Resources and Environment, Graduate University of Chinese Academy of Sciences, Beijing 100049, China). China Environmental Science, 2010,30(10)：1309~1315

Abstract：One–year monitoring study was conducted to estimate wet N deposition to in Chinese chive planting field of a typical agricultural area at northern bank of Dianchi Lake. Nitrogen volatilization was also investigated in soils of Chinese chive planting fields, in situ field Chinese chive decomposition, and in ditch sewage water. The total wet N deposition was 7.1kg N/hm2 in 2007, about 89% of N deposition occurred during the rainy season of April to September. The cumulative ammonia volatilization loss 35days after N fertilization accounted for 25% of supply N as urea (345 kg N/hm2), about 96% of ammonia volatilization loss occurred during the first 9days after N fertilization. The cumulative N volatilization loss accounted for 27%~38% of total N in the ditch sewage water containing 7~51mg N/L (2.7~25.8mg N/L as NH3-N) within open storage for 12days. Therefore, nitrogen volatilization in Chinese chive planting fields could be one of important sources of atmospheric nitrogen in the present investigation area.

Key words：nitrogen；atmospheric nitrogen deposition；ammonia volatilization；sewage；agricultural solid waste resources；Dianchi Lake

滇池流域大量污染物排放入湖,是导致滇池富营养化的主要原因.探明滇池流域不同污染源及其对水体污染负荷贡献,对制定控制措施具有实际意义.滇池流域污染源主要有化肥氮、磷流失,农村生活污水直排,养殖废物污染,农业固废污染,村居地表径流,大气干湿沉降及底泥释放等.据研究,滇池城郊面源污水(生活污水、养殖废水、农田排水和地表径流)氮浓度大于地面水环境质量标准的Ⅴ类标准[1].滇池流域每年化肥流失2171t氮,农业废弃物产生氮30t,农村生活污水产生氮80t[2],面源和生活源总氮已占入湖总量的89%[3].虽然滇池流域污染途径及通量已有很多研究,但大气沉降氮通量及其源解析则少有涉及.国外研究表明流域水质不仅与地表径流有关,也

收稿日期：2010-02-04

基金项目：国家“863”项目(2005AA601010-02);中科院知识创新工程重要方向项目(KSCX2-YW-N-038)

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