African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6578

Full Length Research Paper

Chloride transport in undisturbed soil columns of the loess Plateau

Beibei Zhou1,2,4, Yanli Jiang2,3, Quanjiu Wang2,4* and Ming’an Shao2,5
1Insistute of Earth Enviroment, Chinese Academy of Science, Xi'an 7100, Shaanxi, China. 2State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China. 3Resources and Environment department, Northwest A&F University, Yangling, 712100, China. 4Institute of Water Resources and Hydro-electric Engineering, Xi’an University of Technology, Xi’an, 710048, China. 5Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
Email: [email protected] or [email protected]

  •  Accepted: 09 August 2011
  •  Published: 26 September 2011

Abstract

In soils containing preferential flow paths, both water and solute can move preferentially, bypassing much of the soil matrix. The object of this study was to examine the effect of preferential solute transport in Changwu (loamy soil) soil and Ansai soil (sandy soil) containing macroporosity. Miscible displacement experiments were conducted with 5 undisturbed soil columns (19.45 cm diameter, 43.5 cm long). Breakthrough curves (BTC’s) of Chloride were measured under water-saturated steady flow conditions. The data were simulated using three conceptual models. The results show that two-flow region model described the preferential solute transport much better than the two-region model and the convection dispersion equation (CDE), especially there were humps in the tailing side. Moreover, distinct double peaks were apparent with the increase of pore water velocity in a loamy soil column. In addition, high pore water velocity and small mass transfer coefficient between the two-flow regions enhanced the development of double BTC peaks.

 

Key words: Breakthrough curves, convection dispersion equation, two-region model, two-flow region model.