In clay soil the movement of water is ________.

• A. More horizontal than vertical
• B. More vertical than horizontal
• C. Only Horizontal
• D. Only Vertical

Answer: (A)

In clay soil, water moves more horizontally than vertically because the pore structure is dominated by extremely small, plate-like pores that create strong capillary forces but very low permeability. The tiny pore throats resist downward flow, so vertical movement through the soil profile is sluggish, while water can readily spread along the finer horizontal paths available between clay particles. This combination causes moisture to spread out laterally near the surface faster than it drains straight down, making horizontal movement the dominant mode in clay soils.