There is a natural tendency towards compaction. Roots can be found permeating the total pore volume, with some fine roots penetrating the granular peds. The root network is generally so profuse that the granules are bound into compound peds, enhancing still further the degree of aggregation. Single-grain structure has somewhat the same appearance, but on the smaller scale of individual sand grains. The granular structure has a predominance of macropores, many very large in size.
Bulk density is low.
Most roots occur in the large pores at the corners of blocks and within the planar channels between the smooth faces of the peds. Some fine roots may penetrate the peds by following fine pores. As I discussed for medium-textured soils, greater resistance to water movement and root penetration occurs here as compared to granular structure, but the conditions are still favorable for good plant growth. Obviously, root penetration direction, water and gaseous movement tends to be at right angles to the axis of the long horizontal pores. Impedance of all sorts is easily understood.