...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The Science of the Total Environment >Nitrogen in river basins: Sources, retention in the surface waters and peatlands, and fluxes to estuaries in Finland
【24h】

Nitrogen in river basins: Sources, retention in the surface waters and peatlands, and fluxes to estuaries in Finland

机译：流域中的氮：来源，滞留在地表水和泥炭地中以及通向芬兰河口的流量

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Nitrogen export from diffuse and point sources and its retention in the major river basins of Finland is quantified and discussed. The estimated total export from river-basins in Finland was 119000 tonnes N a(-1) for the period 1993 to 1998 based on N export from different land use types defined in a GIS-based assessment model, incorporated with estimates of N inputs from atmospheric deposition and point sources. Agriculture contributes 38% of the total export, varying in the range 35-85% in the south-western basins and 0-25% in the northern basins. This estimate of N export from agriculture was based on regional N balances together with data from small agricultural research catchments. Forestry contributes on average 9%, with increasing dominance towards eastern and northern parts of the country: from 2% to 15% in the southern-mid-western Finland basins to 10-30% in the large northern basins. 'Background' N export from forests on both mineral and organic soils contributes 27% on average; in the northern basins it may contribute from 40% up to 90% of the total load. The estimate was calculated based on practically all data available from 42 small, experimental catchments in Finland. Of the total N input to Finnish river-systems, 0% to 68% was retained in surface waters and/or peatlands, with a mean retention of 22%. The highest retention of N (36-61%) was observed in the basins with the highest lake percentages. The lowest retention (0-10%) of N was in the coastal basins with practically no lakes. In the national N mass balance, 38 000 tonnes N a(-1) (32%) was estimated as lake retention and 4000 tonnes N a(-1) (3%) as retention in peatlands. On the basis of mass balances and sensitivity analysis, retention was in most cases estimated to be in the range of 7.5-12.5 kg ha(-1) a(-1) in lakes and 01.5 kg ha(-1) a(-1) in peatlands. The model results were tested using the split-sample technique and uncertainty estimates for different data sources are provided and discussed. (c) 2006 Elsevier B.V. All rights reserved.
机译：定量和讨论了来自扩散和点源的氮出口及其在芬兰主要河流流域的保留。根据基于GIS的评估模型中定义的不同土地利用类型的N出口，并结合来自大气沉积和点源。农业占出口总额的38％，西南流域为35-85％，北部流域为0-25％。农业氮出口量的估算基于区域氮平衡以及小型农业研究流域的数据。林业平均贡献了9％，在该国东部和北部的主导地位不断提高：从芬兰中南部盆地的2％上升到15％，到北部大型盆地的10-30％。从森林到矿物和有机土壤的“背景”氮出口平均贡献了27％；在北部盆地，它可能占总负荷的40％至90％。估计数是根据芬兰42个小型实验流域的几乎所有数据计算得出的。在芬兰河流系统的总氮输入量中，0％至68％被保留在地表水和/或泥炭地中，平均保留率为22％。在湖泊百分比最高的盆地中观察到了最高的氮保留（36-61％）。氮的最低保留率（0-10％）位于几乎没有湖泊的沿海盆地。在全国氮素质量平衡中，估计38 000吨N a（-1）（32％）为湖泊滞留量，而4000吨N a（-1）（3％）为泥炭地滞留量。根据质量平衡和敏感性分析，在大多数情况下，湖泊中的保留量在7.5-12.5 kg ha（-1）a（-1）范围内，在01.5 kg ha（-1）a（-1）范围内）在泥炭地中。使用拆分样本技术对模型结果进行了测试，并提供和讨论了不同数据源的不确定性估计。 （c）2006 Elsevier B.V.保留所有权利。

著录项

相似文献

  • 外文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号