洱海北部2种典型种植制度下农田氮污染负荷研究  

Nitrogen Pollution Load in Farmlands Under Two Typical Farming Systems in the North of Lake Erhai Region

作　　者：王哲[1] 谢杰[1] 方达[1] 吴德意[1] 孔海南[1] 刘爱武 李梅新 刘文祥 

机构地区：[1]上海交通大学环境科学与工程学院,上海200240 [2]大理市农业局,云南大理671003

出　　处：《生态与农村环境学报》2013年第5期625-629,共5页Journal of Ecology and Rural Environment

基　　金：水体污染控制与治理科技重大专项(2009ZX07105003-03;2012ZX07105002-03)

摘　　要：洱海北部区域农村面源污染是富营养化初期湖泊——洱海氮磷负荷的主要来源。以洱海北部2种典型种植制度下的农田为研究对象,采用现场调查与采样分析相结合的方法,定量分析氮的输入通量(农作物施肥、大气降水降尘、灌水和生物固氮)及输出通量(农田收获物和生物脱氮),并计算其对水环境产生的氮污染负荷净排放量(包括农田地表径流和地下渗透流)。结果表明,在水稻-蚕豆种植制度下,农田为环境友好型,基本不向水环境排放氮负荷,净排放量为-30.73 kg·hm-2·a-1,主要氮输入通量为生物固氮(占43.3%),其次为有机肥(占35.0%),且输出通量主要为农作物吸收(占98.5%)。在水稻-大蒜种植制度下,农田为环境污染型,净排放量为306.75 kg·hm-2·a-1,主要氮输入通量为肥料(占84.7%),其中化肥占62.1%,而输出通量中水环境排放占45.4%。水稻-大蒜种植制度亟需采取合理施肥和提高肥料利用率等农田污染防治对策。Rural non-point source pollution in the north of the Lake Erhai Region has been deemed as the main source of nitrogen and phosphorus load in Lake Erhai,which is now in the early stage of eutrophication.Through field investigation and sample analysis in laboratory,quantitative analysis was conducted of N influx through fertilization,precipitation and dusffall,irrigation,biological nitrogen fixation） and N outflux through harvest of crops and biological denitrogenation of farmlands under two different farming systems typical of the area,and calculation of the net discharge of nitrogen pollution load from farmland to water environment through surface runoff and underground flow.Results show that the farmland under the rice-horsebean （Viciafaba） farming system is environmental friendly because it discharges little nitrogen pollution load to the water environment with the net discharge being-30.73 kg · hm-2 · a-1.Its nitrogen influx comes mainly through biological nitrogen fixation （43.3％） and organic fertilizer （35.0％）,while its nitrogen outflux goes principally through plant uptake （98.5％）.However,under the rice-garlic farming system,the farmland can discharge nitrogen as much as 306.75 kg · hm-2 · a-1 into the water environment,which could deteriorate water environment.In this system,fertilizer is the main nitrogen source,contributing 84.7％,of which chemical fertilizer accounts for 62.1％,and about 45.4％ of the nitrogen outflux is discharged into the water environment,which suggests that it is essential to adopt reasonable fertilization and measures to improve fertilizer utilization efficiency so as to prevent N non-point source pollution from the farmland under the rice-garlic farming system to the water environment.

关 键 词：农田 氮 污染负荷 种植制度 洱海流域 

分 类 号：X501[环境科学与工程—环境工程]