Why might a digging fork be preferable to a standard spade when working heavy clay?

Answer

It shatters the soil mass more naturally along existing cleavage planes.

A fork breaks the soil by inserting tines and using leverage, which tends to shatter the mass along natural planes rather than slicing through it like a blade.

Why might a digging fork be preferable to a standard spade when working heavy clay?
moisturesoildiggingclay