摘要
Based on the assumption that solute transport in a semi-infinite soil columnor in a field soil profile can be described by the boundary-layer method, an analytical solution ispresented for the advance of a solute front with time. The traditional convection-dispersionequation (CDE) subjected to two boundary conditions: 1) at the soil surface (or inlet boundary) and2) at the solute front, was solved using a Laplace transformation. A comparison of residentconcentrations using a boundary-layer method and an exact solution (in a semi-infinite-domain)showed that both were in good agreement within the range between the two boundaries. This led to anew method for estimating solute transport parameters in soils, requiring only observation ofadvance of the solute front with time. This may be corroborated visually using a tracer solutionwith marking-dye or measured utilizing time domain reflectometry (TDR). This method is applicable toboth laboratory soil columns and field soils. Thus, it could be a step forward for modeling solutetransport in field soils and for better understanding of the transport processes in soils.
Based on the assumption that solute transport in a semi-infinite soil column or in a field soil profile can be described by the boundary-layer method, an analytical solution is presented for the advance of a solute front with time. The traditional convection-dispersion equation (CDE) subjected to two boundary conditions: 1) at the soil surface (or inlet boundary)and 2) at the solute front, was solved using a Laplace transformation. A comparison of resident concentrations using a boundary-layer method and an exact solution (in a semi-infinite-domain) showed that both were in good agreement within the range between the two boundaries. This led to a new method for estimating solute transport parameters in soils, requiring only observation of advance of the solute front with time. This may be corroborated visually using a tracer solution with marking-dye or measured utilizing time domain refiectometry (TDR). This method is applicable to both laboratory soil columns and field soils. Thus, it could be a step forward for modeling solute transport in field soils and for better understanding of the transport processes in soils.
基金
Project supported by the National Key Basic Research Support Foundation of China (No. 2000018605)
the National Natural Science Foundation of China (Nos. 40025106 and 40371060).
