基于SWAT模型的滇池流域不同施肥情景下农业非点源污染模拟研究

发布时间：2018-07-15 13:06

【摘要】：近年来,滇池水污染问题日益严重,而非点源污染是造成水源污染的主要来源之一。非点源污染受着很多因素影响,其中农田的不合理施肥是形成非点源污染的重要来源,本文选取滇池流域作为研究区域,采用SWAT模型对流域农业非点源污染进行模拟。通过设置不同施肥情景模拟分析施肥量和农业非点源污染负荷的关系,为缓减滇池流域农业非点源污染以及农田合理施肥提供科学依据和决策支持。同时分析污染负荷时空分布特征,以及不同土地利用类型的负荷分布,对滇池流域农业面源污染实施源头控制具有指导和借鉴意义;本文主要工作内容及研究成果如下:(1)利用ArcGIS、Swat Weather及SPAW等软件处理流域的土地利用数据、土壤数据及气象数据,构建适用于SWAT模型的滇池流域基础数据库,根据DEM结合河网水系分布等实际特征将整个流域划分为102个子流域和261个水文响应单元(HRU)。(2)使用SWATCUP 2012及流域水文站实测径流数据对模型进行径流参数的率定和验证,率定期和验证期的R2和Ens参数值均达到SWAT模型参数精度要求,模型模拟流域农业非点源污染具有良好的适用性。(3)通过对SWAT模型农业非点源污染负荷模拟结果进行分析,结果表明,农业非点源污染主要分布于流域中部地带,南北地带分布较少,且降雨量和土地利用方式决定着污染负荷输出。(4)针对研究区三种不同轮作地,分别设置3种不同施肥情景对研究区进行农业非点源污染模拟分析。研究结果表明,农业非点源污染负荷输出量与施肥量存在着显著的正相关关系,且总磷负荷输出变化更显著。在分析不同施肥情景下的各种形态氮负荷输出时,硝态氮变化幅度最大,而有机氮和氮氨无影响。因此为了减少农业非点源污染负荷,应该注重合理科学施肥,即保证作物产量,又能有效控制污染。
[Abstract]:In recent years, water pollution in Dianchi Lake is becoming more and more serious, and non-point source pollution is one of the main sources of water pollution. Non-point source pollution is affected by many factors, of which unreasonable fertilization of farmland is an important source of non-point source pollution. In this paper, Dianchi Lake Basin is selected as the study area, and SWAT model is used to simulate agricultural non-point source pollution. By setting up different fertilization scenarios to analyze the relationship between the amount of fertilization and the load of agricultural non-point source pollution, this paper provides scientific basis and decision support for reducing agricultural non-point source pollution and rational fertilization of farmland in Dianchi Lake Basin. At the same time, the characteristics of spatiotemporal distribution of pollution load and the load distribution of different land use types are analyzed, which is of guiding and referential significance for the implementation of source control of agricultural non-point source pollution in Dianchi Lake Basin. The main contents and results of this paper are as follows: (1) the basic database of Dianchi Lake Basin suitable for SWAT model is constructed by using ArcGIS-Swat Weather and SPAW software to deal with land use data, soil data and meteorological data. According to Dem and the actual characteristics of river network distribution, the whole watershed is divided into 102 subbasins and 261 hydrological response units (HRU). (2). The runoff parameters of the model are determined and verified by SWATCUP 2012 and the measured runoff data of hydrologic stations. The values of R2 and Ens of rate periodic and verification period both meet the precision requirements of SWAT model, and the model has good applicability to simulate agricultural non-point source pollution in watershed. (3) the simulation results of agricultural non-point source pollution load of SWAT model are analyzed. The results showed that agricultural non-point source pollution was mainly distributed in the middle part of the basin, and the distribution of the north and south was less, and the output of pollution load was determined by rainfall and land use patterns. (4) three different rotation plots were studied. Three different fertilization scenarios were set up to simulate the agricultural non-point source pollution in the study area. The results showed that there was a significant positive correlation between the output of agricultural non-point source pollution load and the amount of fertilizer, and the change of total phosphorus load output was more significant. In the analysis of the output of various forms of nitrogen load under different fertilization scenarios, the change of nitrate nitrogen was the largest, while organic nitrogen and nitrogen ammonia had no effect. Therefore, in order to reduce the load of agricultural non-point source pollution, we should pay attention to rational and scientific fertilization, that is, to ensure crop yield and to effectively control pollution.
【学位授予单位】：云南师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X71;X52

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