SOIL PHYSICS: TWENTY-FIVE YEARS ON1

Summary In comparison with the situation twenty-five years ago, the analysis of soil-water hysteresis has been transformed by the concepts of independent and non-independent domains, and the analysis of the diffusion-like movement of water in unsaturated soil has led to a theory of the development of water content profiles which was only vestigial at the time of the founding of the British Society of Soil Science. The theory of the control of ground water has greatly developed, mostly along established lines, as also have field methods of determining the hydraulic conductivity necessary for the application of this theory. In striking contrast, the debate about the assessment of soil texture pursues its course unchanged.