Accurate assessment of the fate of salts, nutrients, and pollutants in natural, heterogeneous soils requires a proper quantification of both spatial and temporal solute spreading during solute movement. The number of experiments with multisampler devices that measure solute leaching as a function of space and time is increasing. The breakthrough curve (BTC) can characterize the temporal aspect ...

Time-domain reflectometry (TDR) is an electromagnetic technique for measurements of water and solute transport in soils. The relationship between the TDR-measured dielectric constant (Ka) and bulk soil electrical conductivity (cra) to water content (8W) and solute concentration is difficult to describe physically due to the complex dielectric response of wet soil. This has led to the developmen...

To evaluate and parametrize transport models for the vadose (partially water-unsaturated) zone, information about the spatial distributions of solutes is needed. We describe a technique for the simultaneous imaging of several fluorescent tracers in structured field soils. With this technique, we obtain information on local mixing under field conditions. Local dispersion is a decisive process th...

ity D/v (L), that can be related solely to characteristics of the porous medium (Fried and Combarnous, Dispersivity ( ) is a required input parameter in solute-transport 1971). Dispersivity is a required input parameter in conmodels based on the advection-dispersion equation (ADE). Normally is obtained from miscible-displacement experiments. This depentaminant transport models based on the ADE ...

Modelling solute transport in an unsaturated zone (vadose) depends very much on the simulation of soil moisture and moisture fluxes, which are strongly influenced by precipitation, evapotranspiration, surface runoff and land-surface properties. To provide good approximations of soil moisture and moisture fluxes, a model capable of simulating land-surface processes is required. In this study, a ...

Arid soils in Egypt display large variability in solute transport properties, causing problems in soil management. To characterize this variability, dye infiltration experiments were conducted on four plots representing three main soil types in northeastern Egypt. The plots represented both cultivated and uncultivated land use. The observed dye patterns displayed a large variability and especia...

soil water retention curve (swrc) is important in the studies of soil and water relationship, soil conservation, irrigation scheduling, drainage, solute transport, plant growth and crop water stress. the performance of 10 models (simons et al., libardy et al., campbell, farrell and larson, van genuchten, brooks and corey, driessen, exponential bruce-luxmore, power bruce-luxmore, and rogowski) w...

Dalton, F.N. and van Genuchten, M.Th., 1986. The time-domain reflectometry method for measuring soil water content and salinity. Geoderma, 38: 237--250. This paper discusses the physical principles and use of time-domain reflectometry as a new tool for studying water and solute transport in unsaturated soils. In-situ measurements of water content and bulk soil electrical conductivity are shown ...