• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Modeling physical and chemical nonequilibrium transport of herbicide in soils from different tillage systems.
【24h】

Modeling physical and chemical nonequilibrium transport of herbicide in soils from different tillage systems.

机译：模拟不同耕作系统中除草剂在土壤中的物理和化学非平衡迁移。

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

The physical and chemical nonequilibrium transport of alachlor were studied in a surface Gigger soil from different tillages through tracer studies, and batch and miscible displacement experiments. Batch experiments indicated initially fast reaction followed by slow adsorption. Adsorption and desorption results indicated time dependent hysteretic behavior and was best described by a multireaction model incorporating nonlinear equilibrium reaction, a reversible kinetic mechanism, and a consecutive irreversible mechanism. The model predicted alachlor hysteresis and adsorption-desorption kinetics satisfactorily based on parameters obtained from adsorption experiments.; Tracer (Eosin Y and Blue FCF dyes) studies showed non-uniformly stained areas in undisturbed soil cores (6.4 cm i.d, 15 cm length) and indicated more pronounced preferential flow and physical nonequilibrium solute transport in no-till than in conventional tillage. Tritium breakthrough curves (BTCs) indicated earlier breakthrough associated with bimodal peaks in short pulses for no-till. The shape of BTCs were also dependent on flow direction. The superimposed experimental data from short pulses well predicted the data of long pulses. The classical convective-dispersive equation was inadequate and there was no improvement in describing tritium BTCs using physical nonequilibrium models (mobile-immobile and stochastic models) for soils from no-till.; Miscible displacement results indicated that alachlor BTCs in soils of no-till were more asymmetrical, with earlier breakthrough and longer tailing than soils from conventional tillage. A multireaction transport model (MRTM) was not satisfactory for alachlor prediction using independently measured parameters from batch experiments. However, MRTM successfully described alachlor BTCs in a calibration mode where physical and chemical nonequilibrium were dominant. Best-fit parameters indicated the dominance of kinetic reactions compared with parameters from batch experiments and may be attributed to soil heterogeneity. Although no-till increased alachlor retention in batch experiments, an overall estimation based on the sum of kinetic and equilibrium retention showed no significant influence on retention by tillage. High pressure liquid chromatography (HPLC) chromatograms, fitted transport parameters, flow interruptions and percent recoveries indicated a significant consecutive irreversible reaction in soils of conventional tillage. Moreover, no-till increased alachlor transport based on breakthrough time compared with conventional tillage.
机译：通过示踪研究以及分批和混溶驱替实验，研究了不同耕作的吉格（Gigger）表层土壤中甲草胺的物理和化学非平衡迁移。分批实验表明，最初反应很快，随后吸附缓慢。吸附和解吸结果表明了时间依赖性的滞后行为，并且最好采用结合了非线性平衡反应，可逆动力学机理和连续不可逆机理的多重反应模型来描述。该模型基于从吸附实验获得的参数令人满意地预测了甲草胺的滞后性和吸附-解吸动力学。示踪剂（曙红Y和蓝色FCF染料）研究表明，未耕作的土壤核心（6.4厘米内径，15厘米长）上的染色区域不均匀，并且免耕比传统耕作更显着的优先流动和物理非平衡溶质运移。 t突破曲线（BTC）表示更早的突破与短脉冲的免耕双峰相关。 BTC的形状还取决于流动方向。来自短脉冲的叠加实验数据很好地预测了长脉冲的数据。经典的对流弥散方程是不充分的，对于使用免耕土壤，使用物理非平衡模型（移动固定和随机模型）描述triBTC并没有改善。混溶位移结果表明，免耕土壤中的甲草胺BTCs比传统耕作的土壤更不对称，具有更早的穿透和更长的拖尾。使用来自批次实验的独立测量参数，多反应传输模型（MRTM）对于甲草胺的预测不令人满意。但是，MRTM在标定模式下成功地描述了甲草胺BTC，在标定模式下，物理和化学非平衡占主导地位。最佳拟合参数表明，与批处理实验参数相比，动力学反应占主导地位，并且可能归因于土壤异质性。尽管在分批实验中免耕增加了甲草胺的保留量，但基于动力学和平衡保留量之和的总体估算结果显示，耕作对保留量无显着影响。高压液相色谱（HPLC）色谱图，拟合的运输参数，流量中断和回收率百分比表明，在传统耕作土壤中发生了连续的不可逆的显着反应。此外，与常规耕作相比，免耕法在突破时间的基础上增加了甲草胺的转运。

著录项

  • 作者

    Xue, Shikui.;

  • 作者单位

    Louisiana State University and Agricultural & Mechanical College.;

  • 授予单位 Louisiana State University and Agricultural & Mechanical College.;
  • 学科 Agriculture Soil Science.; Environmental Sciences.; Chemistry Agricultural.; Agriculture Agronomy.
  • 学位 Ph.D.
  • 年度 1996
  • 页码 156 p.
  • 总页数 156
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 土壤学;环境科学基础理论;农业化学;农学（农艺学）;
  • 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