Length differences of vertical and horizontal cracks are negligible. Soil peds often have thin, discontinuous, clay films on surfaces and tend to break more easily along the vertical axis than in the very slowly permeable soils. Soils frequently have thick surface and transitional horizons from the surface to the most clayey horizon in the profile. Soils that have dense, fine-textured subsoils and claypan soils are very slowly permeable. Their structure is coarse, angular blocky or massive with very few visible pores.
Roots are few and generally follow ped faces and cracks.
These subsoils are very firm when moist and very hard when dry. Soil peds have thick, continuous, clay films on surfaces. Horizontal cracks are longer than vertical ones. Surface Runoff Surface runoff is the relative rate water is removed by flowing over the soil surface. This includes rainfall, as well as water from adjacent slopes.