Spatial variability of solute transport mechanisms based on generalized transfer function model

The flexible generalized transfer function model (GTF) and TDR based time normalized resident concentrations were combined in order to characterize solute transport mechanism both at local and field scale. A leaching experiment was carried out in a plot under greenhouse, where TDR probes were installed at three different depths at 37 sites along a 40 m transect. The field plot was brought to steady-state water content; a pulse application of 3.87 mm of KCl solution was applied. Measurements of water content (θ) and impedance (Z) were simultaneously taken to follow the KCl solution propagation through the soil profile. Time series of relative resident concentrations for each site where effectively interpreted in terms of GTF model. The field scale behavior was described by calculating a local average and an integral average, by averaging local scale parameters and local scale original measurements, respectively. The two different averaging schemes resulted in two significantly different field scale solute transport behaviors.