首页> 外文学位 >Optimizing carbon to nitrogen ratios to improve nitrogen removal in agricultural drainage ditches.
【24h】

Optimizing carbon to nitrogen ratios to improve nitrogen removal in agricultural drainage ditches.

机译:优化碳氮比,以改善农业排水沟中的氮去除率。

获取原文
获取原文并翻译 | 示例

摘要

Since 1961, a four-fold increase in application of fertilizers in the United States has helped to double crop yields. Nutrients not used by crops are often transported to aquatic ecosystems adjacent to agricultural fields. In the Lower Mississippi Alluvial Valley, nutrients enter agricultural drainage ditches and are transported to receiving water bodies, eventually reaching the Gulf of Mexico. The annual occurrence of a hypoxic zone in the Gulf of Mexico is caused by nitrogen loads from the Mississippi River Basin. Objectives of these studies were: (1) evaluate how organic carbon amendments affect nitrate-nitrogen removal in agricultural drainage ditch systems, (2) determine effects of organic carbon amendments and flow rate on nitrate-nitrogen removal in a semi-controlled field setting using experimental drainage ditches, and (3) assess relationships between organic carbon and nitrogen content of overlying water, pore water, and sediments of drainage ditches throughout the Lower Mississippi Alluvial Valley. In laboratory experiments, nitrate-nitrogen removal in dissolved and particulate organic carbon treatments was greater than 90% compared to as low as 60% in control treatments. The optimal carbon-to-nitrogen ratio of organic carbon amendments for efficient nitrate-nitrogen removal was 5:1. Studies in experimental drainage ditches revealed that flow substantially lowered the ability of organic carbon amendments to remove nitrate-nitrogen with a maximum percent nitrate-nitrogen reduction of 31.6% in a dissolved organic carbon treatment, although implementation of low-grade weirs in experimental drainage ditches did result in removal of nitrate nitrogen in all treatments and at all flow rates. Examining the nitrogen and organic carbon contents in agricultural drainage ditches throughout the Lower Mississippi Alluvial Valley revealed that organic carbon content in overlying water, pore water, and sediments is lower than observed in other wetland-like ecosystems and indeed may be limiting denitrification and other nitrogen removal processes. Increasing organic carbon content overall could be achieved by using organic carbon amendments, but this body of research highlights that additional studies are necessary to ensure successful implementation of organic carbon amendments that reach their greatest potential as a management practice to effectively remove nitrate-nitrogen in the realistic settings of agricultural drainage ditches.
机译:自1961年以来,美国的肥料用量增加了四倍,使农作物的产量翻了一番。作物未使用的养分通常被运输到农田附近的水生生态系统中。在下密西西比河冲积河谷,养分进入农业排水沟并被输送到接收水体,最终到达墨西哥湾。密西西比河流域的氮负荷造成了墨西哥湾缺氧区的年发生。这些研究的目的是:(1)评估有机碳改良剂如何影响农业排水沟系统中硝酸盐-氮的去除,(2)确定有机碳改良剂和流速对半控制田间环境中硝酸盐-氮去除的影响实验性排水沟,以及(3)评估整个密西西比河冲积河谷上覆水,孔隙水和排水沟沉积物中有机碳和氮含量之间的关系。在实验室实验中,溶解和颗粒有机碳处理中硝酸盐氮的去除率大于90%,而对照处理中的硝酸盐氮去除率则低至60%。有效去除硝态氮的最佳有机碳改性剂碳氮比为5:1。在实验排水沟中进行的研究表明,尽管在实验排水沟中实施了低等级堰,但流量显着降低了有机碳改良剂去除硝酸盐氮的能力,在溶解有机碳处理中硝酸盐氮减少的最大百分比为31.6%。确实在所有处理过程中和所有流速下都去除了硝酸盐氮。对整个密西西比河下游冲积河谷的农业排水沟中的氮和有机碳含量进行检查后发现,上覆水,孔隙水和沉积物中的有机碳含量低于其他类似湿地生态系统的有机碳含量,确实可能限制了反硝化作用和其他氮含量清除程序。通过使用有机碳改良剂可以总体上提高有机碳含量,但是该研究机构强调,有必要进行额外的研究以确保成功实施有机碳修正剂,从而最大程度地发挥其作为管理实践的潜力,从而有效地去除有机碳中的硝酸盐氮。农业排水沟的实际设置。

著录项

  • 作者

    Faust, Derek Ronald.;

  • 作者单位

    Mississippi State University.;

  • 授予单位 Mississippi State University.;
  • 学科 Water resources management.;Agriculture.;Aquatic sciences.
  • 学位 Ph.D.
  • 年度 2016
  • 页码 112 p.
  • 总页数 112
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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