• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Water, Air, and Soil Pollution >EXPORT OF DISSOLVED INORGANIC NITROGEN IN A PARTIALLY CULTIVATED SUBTROPICAL MOUNTAINOUS WATERSHED IN TAIWAN
【24h】

EXPORT OF DISSOLVED INORGANIC NITROGEN IN A PARTIALLY CULTIVATED SUBTROPICAL MOUNTAINOUS WATERSHED IN TAIWAN

机译：台湾部分栽培的亚热带山地流域中溶解性无机氮的出口

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

A spatial and temporal investigation of dissolved inorganic nitrogen (DIN; NO_3, NO_2 and NH_4 was conducted under various water discharge conditions in Lanyang-Hsi, a subtropical mountainous stream, which drains through distinct degrees of agriculture-influenced sub-watersheds. In both the cultivated and non-cultivated sub-watersheds, NO_3 was the most abundant species accounting for >80% of total DIN, while NH_4 and NO_2 accounted for < 15% and 5% of DIN, respectively. Agricultural activities along the riverbank led to significantly higher NO_3 concentrations (13-246 μM) and DIN yields (1300-3800 kg N km~(-2) yr~(-1)) in main channel when compared to those of non-cultivated tributaries (9-38 μM for NO_3 and 550-740 kg N km~(-2) yr~(-1) for yield). The much lower and less variable DIN yields observed in tributary stations (mean = 660 ± 120 kg N km~(-2) yr~(-1)) are considered as the present day background of DIN yield, which is significantly higher than those of most natural watersheds in other regions. Elevated atmospheric DIN deposition is likely the cause for the high background DIN yield. Human activity within the watershed results in additional DIN yield, which accounted for 49% of total N export. However, the reported atmospheric DIN input in northern Taiwan (～1800 kg N km~(-2) yr~(-1)) is much higher than the background DIN yield implying that a major fraction (70%) of atmospheric inputs are retained or processed within the watershed. A dilution pattern occurred in the main channel where high NO_3 concentrations from the upstream sources decreased significantly in downstream direction due to inputs of NO_3-diluted water from non-cultivated areas. We adopted a two-source mixing model to predict the NO3 dilution pattern. This model revealed a third yet not recognized N source in the lower part of watershed. Model results also indicated the importance of water discharge rate in regulating the relative contribution to total DIN export among these sources.
机译：在亚热带山区河流兰阳西溪，在不同的排水条件下，通过不同程度的农业影响子流域排水，对溶解的无机氮（DIN，NO_3，NO_2和NH_4）进行了时空调查。在耕作和非耕作的小流域中，NO_3是最丰富的物种，占DIN总量的80％以上，而NH_4和NO_2分别占DIN的<15％和5％。与未耕作的支流相比，主通道的NO_3浓度（13-246μM）和DIN产量（1300-3800 kg N km〜（-2）yr〜（-1））（NO_3和NO_3的9-38μM 550-740 kg N km〜（-2）yr〜（-1））。在支流站观察到的DIN产量低得多而又少（平均= 660±120 kg N km〜（-2）yr〜（ -1））被认为是DIN产量的当前背景，大大高于大多数自然流域的背景在其他地区。大气DIN沉积的升高可能是导致本底DIN产率高的原因。流域内的人类活动导致增加的DIN产量，占氮出口总量的49％。然而，据报道台湾北部的大气DIN输入（〜1800 kg N km〜（-2）yr〜（-1））远高于背景DIN的产量，这意味着大部分（70％）的大气输入得以保留或在分水岭内处理。稀释模式出现在主通道中，由于来自非耕地的NO_3稀释水的输入，上游来源的高NO_3浓度沿下游方向显着降低。我们采用两源混合模型来预测NO3稀释模式。该模型揭示了流域下部的第三个尚未识别的氮源。模型结果还表明，在调节这些水源对DIN出口总量的相对贡献中，排水速率的重要性。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 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