6.3 Solute Transport: Theoretical Background

The transport of solutes in soils has always been of interest in agronomy because of the impact that nutrient and salt concentrations have on conditions for plant growth. During the last few decades, interest in solute transport has broadened due to concerns about the fate of chemicals in the subsurface environment, particularly with regard to the possible contamination of soil and groundwater by agricultural and industrial chemicals. Although significant progress has been made, the quantitative description of solute transport in soils remains a challenging and active area of research. In this section we review basic theoretical concepts and models for solute transport in soils (miscible displacement). Later sections discuss experimental procedures (Section 6.4) and methods of data analysis (Section 6.5).