Which soil structure has poor infiltration and poor aeration?

• A. Granular
• B. Platy
• C. Massive
• D. Blocky

Answer: (C)

The main idea here is how soil structure controls the connected pore network that water and air move through. In a massive soil structure, you don’t see distinct peds or aggregates—the soil forms a single, dense block with very little interconnected porosity. That means water can’t find many pathways to infiltrate, so infiltration is slow, and air can’t move through easily, so aeration is poor as well.

This is different from granular structure, which consists of many small, rounded aggregates with lots of interconnected pores, giving rapid infiltration and good air movement. Platy structure stacks into thin plates that can impede vertical water flow and drainage, often hindering drainage and reducing aeration. Blocky structure has visible peds that create some channels for movement, offering better drainage and aeration than massive but still not as favorable as granular.

So, the structure described as massive best explains both poor infiltration and poor aeration because its dense, unaggregated form limits pore connectivity and airflow.