Which soil structure is block-like, with flat or slightly rounded faces and angular blocky when faces intersect at relatively sharp angles?

• A. Prismatic
• B. Structureless
• C. Blocky
• D. Granular

Answer: (C)

Think about how soil particles group into aggregates, or peds, and what they look like. A blocky structure is made of roughly cube- or rectangular-shaped peds with flat faces (or faces that are only slightly rounded). When those faces meet, they form relatively sharp, angular edges and corners, giving a clearly blocky appearance. This is common in clay-rich soils where particles bind into distinct blocks.

Prismatic structure would be column-like, with elongated vertical peds and flat top and bottom faces. Granular structure consists of loose, rounded grains that don’t form distinct blocks. Structureless means no recognizable ped organization.