This is a new edition of the book previously titled Solute Movement in the Soil-Root System, and describes in detail how plant nutrients and other solutes move in the soil in response to plant uptake. It provides a basis for understanding processes in the root zone so that they can be modelled realistically in order to predict the effects of variations in natural conditions or our own practices. The new edition brings the text up-to-date, and it will be less technical.