Soil water balance and transport processes - Review of theory and field applications

The theory of soil water balance and transport processes is reviewed. The main subjects are : measurement of crop water consumption ; principles of soil water behaviour ; measuring techniques of soil water content and potential, such as dielectric methods, the gravimetric method, neutron scattering techniques, and the use of piezometers and tensiometers ; theory, principles and applications of time-domain reflectometry ; water transport at the soil-root interface ; and the soil water balance approach to crop water requirement studies.
Applications to soil water management in agriculture include : determination of the direction and quantity of soil water flow ; determination of the soil water characteristic curve or retentivity curve ; irrigation scheduling ; measurement of unsaturated hydraulic conductivity ; and measuring crop evapotranspiration in the field.