紫色土丘陵区典型小流域非点源氮磷迁移的模拟研究
文献类型：学位论文
| 作者 | 张剑 |
| 学位类别 | 博士 |
| 答辩日期 | 2009 |
| 授予单位 | 中国科学院水利部成都山地灾害与环境研究所 |
| 授予地点 | 成都 |
| 导师 | 朱波 |
| 关键词 | 紫色土丘陵区 截流小流域 非点源氮磷污染 AnnAGNPS模型 BMPs |
| 其他题名 | Modelling on non-point-source nitrogen and phosphorus transport in a typical catchment in the hilly area of purple soils,China |
| 学位专业 | 自然地理学 |
| 中文摘要 | 紫色土丘陵区处于长江上游生态屏障的最前沿，是长江流域、三峡水库水环境的重要影响区。该区农业非点源污染负荷逐年增加，水环境恶化趋势日益突出。在大量查阅国内外文献基础上，实地踏勘、调研，了解紫色土丘陵区农村小流域的基本景观特征，选取典型小流域(截流小流域)，通过连续野外定位观测，查明小流域非点源污染特征，并以AnnAGNPS非点源污染模型框架为基础，构建小流域非点源污染模型，为紫色土丘陵区农业非点源污染预测和评价提供可利用的模型及应用经验，对保护紫色土丘陵区乃至长江上游的水环境，优化水资源的管理具有重要的理论和实践意义。本研究的主要结论如下： (1)非点源污染特征 通过2004-2008年对截流小流域径流、泥沙和氮磷负荷的长期观测表明： 月径流深与月降雨量存在着显著的线性相关关系y=0.4715x+5.8302(R2=0.5074， p<0.01， n=60)； 土壤侵蚀主要发生在每年的5-9月间，输沙量介于231.9-392.9t·a-1，侵蚀模数介于662.6-1122.6 t/km2.a-1； 总氮负荷介于11.8-16.2 kg·hm-2，总磷负荷介于1.33-1.96 kg·hm-2，其中降雨-径流产生的负荷，总氮介于8.86-10.47 kg.hm.2:总磷介于1.19-1.61 kg·hm-2； 非点源污染的季节变化明显，与流域降水的季节变化基本一致，主要集中在5-9月，降雨-径流是溶解态氮磷的主要流失方式，土壤侵蚀是颗粒态氮磷的主要流失方式，其中，氮的流失以溶解态为主，磷的流失以颗粒态为主。 (2)模型适用性检验 运用数字滤波法对截流小流域径流进行了基流分割，通过径流曲线CN、作物覆盖度因子C、水土保持因子P、土壤理化性质等重要参数的率定，对AnnAGNPS模拟结果进行了校准和验证。 直接径流方面：在校准期的2004-2005年尺度上，校准结果为相对偏差-11.3%，Ens系数0.66；月尺度上，相对偏差分别为-22.1%和0.06%，R2分别为 0.98和0.93，Ens系数分别为0.81和0.93；在验证期的2006-2008年尺度上，相对偏差2.0%，Ens系数为0.72；月尺度上，相对偏差分别为2.7%，-2.6%和-1.7%，R2分别为0.99，0.97和0.98，Ens系数分别为0.98，0.99和0.98； 泥沙方面：校准期2008年，输沙量结果的相对误差为5.0%，验证期，2004-2007年输沙量模拟的相对误差为5.8%，R2为0.91，Ens系数分别为0.89； 氮磷负荷方面：校准期(2008年)TN和IP的模拟偏差分别为26.1%和21.6%，DN和DP的模拟偏差分别为17.2%和-18.5%，PN和PP的模拟偏差分别为-13.4%和30.8%，而对于验证期(2004-2006年)TN和TP的年模拟偏差分别为9.0%和3.6%： 以上结果表明，该模型较为适用于该紫色土丘陵区小流域。 (3)模型模拟结果 应用经过修正的模型，模拟2007年小流域非点源氮磷输出过程。结果表明，在时间上，6-8月是氮磷迁移的高峰期，总氮和总磷负荷分别占全年的91.5%和98.7%；空间上，非点源产生的氮磷负荷分布主要集中在坡度较大的区域；通过参数的敏感性分析可知，地形、降雨-径流、农田管理措施和土地利用类型等对产流、产沙以及氮磷迁移的通量有重要的影响； (4)情景模拟及BMPs 小流域不同土地利用类型的单位面积非点源氮磷负荷有较大的不同，总氮负荷贡献率大小依次为旱地、水田、居民点和林地，总磷负荷贡献率大小依次为旱地、林地、水田和居民点。不同管理措施BMPs对氮磷负荷影响的模拟结果表明，建立合理的施肥制度、实行退耕还林、坡改梯等水土保持措施、改善耕作方式，实行保护性耕作以及农村城镇生活污水生态工程控制措施可有效减轻小流域的非点源氮磷污染。 |
| 英文摘要 | The hilly area of purple soils is at forefront of ecological barriers in the upper Yangtze River. It is important for water environment protection for Yangtze River basin and three gorges reservoir. Rural water environment of catchment is serious deterioration, and loads of agricultural non-point source pollution increase year by year in the hilly area of purple soils. After consulting domestic and foreign literature, field survey was conducted to find out the basic landscape characteristics of rural catchment of the hilly area of purple soils. A typical catchment (Jieliu catchment) was selected for continuous in situ field observation and simulation, basic characteristics of non-point source pollutants transport in the catchment were known. Based on AnnAGNPS model framework, the non-point source pollution model of the catchment was built by the database and calibration and verification. It provided a scientific basis for evaluation and prediction of agricultural non-point source pollution in the hilly area of purple soils. It was also important to protect the Yangtze River Basin and to optimize the management of water resources. The main conclusions of this study are as follows: 1. The characteristics of nonpoint source pollution A significant linear correlation was existed in the actual observation for monthly runoff and monthly rainfall from 2004 to 2008(R2=0.5074，p<0.01，n=60). Soil erosion occurs mainly in between May to September each year. The sediment loadings was ranged from 231.9 t•a-1to 392.9 t•a-1 and erosion modulus was ranged from 662.6 t/km2•a-1 to 1122.6 t/km2•a-1 from 2004 to 2008. The total nitrogen load ranged from 11.8 kg•hm-2 to 16.2 kg•hm-2, and total phosphorus load ranged from 1.33 kg•hm-2 to 1.96kg•hm-2. The non-point source load of total nitrogen ranged from 8.86 kg•hm-2 to 10.47 kg•hm-2, and total phosphorus ranged from 1.19 kg•hm-2 to 1.61 kg•hm-2. It was evidence to seasonal changes of non-point source pollution, corresponding with the seasonal variation of rainfall, mainly focus on the May to September in the catchment. The main loss form of dissolved nitrogen and dissolved phosphorus was by rainfall-runoff. The main loss form of particulate nitrogen and particulate phosphorus was by soil erosion. The loss of nitrogen was mainly dissolved, and the loss of phosphorus was based on particulate. 2. Evaluation of AnnAGNPS model performance As for runoff, the relative deviation was -11.3%, ENS coefficient was 0.66 on the year scale in calibration period. The relative deviations were from -22.1% to 0.06%. R2 were from 0.98 to 0.93. ENS coefficients were from 0.81 to 0.93 on the monthly scale in calibration period. The relative deviation was 2.0%, ENS coefficient 0.72 on the monthly scale in validation period. The relative deviations were from -2.6% to 2.7%. R2 were from 0.97 to 0.99. ENS coefficients were from 0.98 to 0.99 on the monthly scale in validation period. As for sediment, the relative deviation was 5.0% on the year scale in calibration period. The relative deviation was 5.8%. R2 was0.91.ENS coefficient was 0.89 on the year scale in validation period. As for nitrogen and phosphorus load, the relative deviations were 26.1% and 21.6% of TN and TP on the year scale in calibration period, respectively. The relative deviations were 5.6% and 3.7% of TN and TP on the year scale in validation period, respectively. As a result, the model was a good simulation of the catchment. 3. Modeling results Based on the results of simulation in 2007, the peak period of nitrogen and phosphorus transport was between June and August in temporal. The nitrogen and phosphorus loads accounted for 91.5% and 98.7% in this time, respectively. The distribution for nitrogen and phosphorus load generated by non-point source mainly occurred to steep slope. The topography, rainfall-runoff, farmland management practices and landuse types had important influence on runoff volume, sediment yield and nitrogen and phosphorus transport by sensitivity analysis of parameters. 4. Scenario simulation and BMPs The results of model showed that there was difference in non-point source nitrogen and phosphorus loads for different landuse types per unit area in the catchment. The contribution rate of total nitrogen load was dry land, paddy fields, settlements, and forest land in turn, and the contribution rate of total phosphorus load was dry land, forest land, paddy fields, settlements and in turn. Modeling BMPs result of different management measures on the impact of nitrogen and phosphorus load showed that some measures, such as reusing farmland for forest, farmland changed terrace and conservation tillage, could minify loads of nitrogen and phosphorus from non-point source pollution in the catchment. |
| 学科主题 | 土壤学 |
| 语种 | 中文 |
| 公开日期 | 2010-10-13 |
| 分类号 | S15;F30 |
| 源URL | [http://ir.imde.ac.cn/handle/131551/2170]  |
| 专题 | 成都山地灾害与环境研究所_成都山地所知识仓储（2009年以前） |
| 推荐引用方式 GB/T 7714 | 张剑. 紫色土丘陵区典型小流域非点源氮磷迁移的模拟研究[D]. 成都. 中国科学院水利部成都山地灾害与环境研究所. 2009. |
入库方式： OAI收割
来源：成都山地灾害与环境研究所
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