In which condition would a clod be described as 'friable'?

A clod is described as 'friable' when it crumbles or breaks apart under moderate pressure, indicating that it has a desirable texture for agronomic purposes. When soil is friable, it typically has good aeration and drainage, allowing roots to penetrate easily and promoting healthy plant growth. This type of soil is composed of small aggregate particles that can be broken down without significant effort, suggesting that it retains some structure while still being workable.

The other conditions do not align with the definition of friable. If a clod fails under very slight pressure, it suggests that the soil is excessively loose or disintegrated, lacking the cohesion that defines friability. Conversely, if a clod holds together under all pressures, it indicates a compact or dense condition, which is opposite to what friable soil characteristics are meant to convey. Finally, if the clod feels very hard to touch, it indicates a lack of softness and crumbliness, which are hallmarks of friable soil texture. Thus, friability represents a balanced state where soil is manageable and supportive for growth.