ABSTRACT
The total potential ct of soil water refers to the potential energy of water in the soil with respect to a defined reference state. Various components of this potential control water flow in the soil (Chaps. 4, 5, and 6), from the soil into roots, and through plants. Matric potential refers to the tenacity with which water is held by the soil matrix (Marshall, 1959). In the absence of high concentrations of solutes, it is the major factor that determines the availability of water to plants. After allowing for differences in elevation, differences in matric potential between different parts of the soil drive the unsaturated flow of soil water (Chap. 5).
