A real undisturbed soil-column infiltrating experiment in Zibo, Shandong, China, is investigated, and a nonlinear transport model for a solute ion penetrating through the column is put forward by using nonlinear Freundlich’s adsorption isotherm. Since Freundlich’s exponent and adsorption coefficient and source/sink terms in the model cannot be measured directly, an inverse problem of determinin...

Many studies of water flow and solute transport in the vadose zone require estimates of the unsaturated soil hydraulic properties, including the soil water retention curve ~WRC! describing the relationship between soil suction and water content. An artificial neural network ~ANN! approach was developed to describe the WRC using observed data from several soils. The ANN approach was found to pro...

Water repellency of soils near the surface leads to preferential flow and transport, because it prevents water from entering hydrophobic areas and concentrates water fluxes in hydrophilic areas. Heterogeneity in the flow field is the main problem for the prediction of contaminant transport. To investigate the flow patterns in a sandy soil, which was contaminated with hydrophobic tar oils and he...

The Plant Protection Product Directive (91/414/EEC) stresses the need of validated models to calculate predicted environmental concentrations. The use of models has become an unavoidable step before pesticide registration. In this context, the European Commission set up a FOrum for the Co-ordination of pesticide fate models and their USe (FOCUS). The main topic of research presented here is the...

There is a limited understanding of solute transport properties of degraded peat soils as compared to mineral substrates. A lower organic matter (OM) content is often the result of peat degradation and mineralization following artificial drainage. In this study, we aimed at deducing changes in solute transport properties of peat soils differing in OM content. Miscible displacement experiments w...

Rapid movement of agricultural chemicals through soil to groundwater via preferential flow pathways is one cause of water contamination. Previous studies have shown that time domain reflectometry (TDR) could be used to characterize solute transport in soil. However, previous studies have only scarcely addressed preferential flow. This study presents an extended application of TDR for determinin...

LEACHP is a modular package for calculating the one-dimensional vertical water and solute ̄ux in horizontally layered soils under transient conditions. Data from ®eld studies conducted in a sandy soil (Vredepeel, The Netherlands) and in a loamy soil (Weiherbach, Germany) were used by ®ve groups to simulate water ̄ow and bromide and pesticide transport with the LEACHP model. Calibrated outputs w...

A simple modeling and laboratory investigation was carried out to investigate the raindrop effects on both sediment detachment and chemical transport from soil–water into runoff. Solute movement between soil–water and runoff is usually modeled as either a mixing model or as a diffusion-like process, both of which ignore the important roles of raindrop impact on the transport process. We hypothe...