The study of soil physics is now recognised as an important aspect of agriculture. The maintenance of crumb structure in wheat soils, increasing the infiltration rate on land liable to erosion, the subsurface drainage of horticultural soils, the supply of adequate moisture to irrigated crops, and the prevention of seepage from rice fields are examples of the necessity for understanding the physics of soil. Methods of measurement of such properties are now available to give a reliable picture, and some of these are reported in the first part of this paper for several Victorian soils - there is indeed a lack of such information.
However there is a greater deficiency in the understanding of the fundamental reasons of why a soil has the physical properties that it displays. Subsoil permeability has been investigated and is reported on and discussed in the second part of the paper.