基于模型的上海郊区地下水氮素非点源污染特征研究  

Modeling Impacts of Cropland Non-point Source Nitrogen Pollution on Groundwater in a Suburban Area of Shanghai, China

作　　者：黄秀梅[1] 申广荣[1] 周培[1] 

机构地区：[1]农业部都市农业(南方)重点开放实验室,上海交通大学,上海200240

出　　处：《农业环境科学学报》2011年第7期1378-1384,共7页Journal of Agro-Environment Science

基　　金：2008年上海自然基金项目(09ZR1415200);上海市科委重大项目(08dz1900404)

摘　　要：农业非点源污染是造成上海郊区地下水污染的主要因素,定量分析预测农业生产过程氮素的迁移转化规律是有效控制地下水污染的重要环节。以上海市浦东新区新场镇果园村的桃园为研究对象,借助生物地球化学过程模型(DNDC)和长期水文影响评价模型(L-THIA),基于连续观测数据,详细分析了农业生产过程中氮素造成的非点源污染,特别是对周边地表、地下水的影响。结果表明,地表水总氮均值达6.34mg·L-1,远劣于地表水Ⅴ类标准(≤2.0mg·L-1);地下水中总氮均值达16.85mg·L-1,远劣于地表水Ⅴ类标准(≤2.0mg·L-1)。约有20%采样点硝态氮含量属于地下水Ⅴ类(>30mg·L-1)。野外检测数据表明,该区地表水、地下水污染均严重超标,不宜饮用。模型分析显示,水体污染源主要来自桃园生产中施用的肥料,其中就模拟结果的数值可以得出,大约年农田氮输入量的1.7%通过土壤径流进入地表水,约3.5%经过土壤渗漏进入地下水,实测地下水中氮含量占桃园总氮输入量的5.8%。因此,合理调整施肥措施和施肥结构是减少土壤-水体中氮素污染的有效途径。Non-point source pollution has been recognized as a major factor causing groundwater contamination in suburban areas of Shanghai. It＇s crucial for mitigating the groundwater contamination to quantify leaching losses of nitrogen（ N ） from the agricultural fields. This paper reports a study on N hiogeoehemical cycling with field measurement and model simulation for a typical orchard planted with peach and vegetables in Guoyuan Village, Xinchang Town, Pudong District, Shanghai. Samples of surface water, groundwater and soil were collected and analyzed to obtain N contents in the agro-ecosystem. The results showed that both of the surface and groundwater were polluted so seriously that they were not suitable to drink. The average content of total nitrogen in surface water was 6.34 mg·L^-1 and 16.85 mg· L^-1 in the groundwater, both of them were over the standard of Grade V surface water（ ≤2.0 mg·L^-1） according to the national standard （GB 3838-2002 ）. In addition, the content of nitrate nitrogen from about 20% of the sampling sites fell into Grade V groundwater （〉30 mg· L^-1 ） based on the national standard（ GB/T14848--1993 ）. Two models, a process-based biogeochemieal model DNDC and a empirical hydrologic model L-THIA, were employed to interpret and extrapolate field observations. The modeled results indicated that about a half of the total N input of 581 kg N ·hm^-2-a^-1 were absorbed by the crops and lost as N gases, and about 293 kg N·hm^-2-a^-1 were accumulated in the soil and hence became available for leaching loss. L-THIA simulated N losses through leaching and found about 1.7% of annual accumulated soil N leached into the surface water via the surface runoff and 5.8% to the groundwater and 3.5% in the soil liquid phase. The methodologies utilized in the study could serve groundwater pollution mitigation related to agricultural production in Shanghai.

关 键 词：L-THIA模型 氮素含量 非点源污染 DNDC 桃园 

分 类 号：X523[环境科学与工程—环境工程]