The correct option is Gully erosion.
Explanation
Soil erosion is the displacement of the upper layer of soil. Water erosion typically progresses through specific stages based on intensity and impact: splash, sheet, rill, and gully erosion.
Analysis of Erosion Types:
- Gully Erosion (Correct): This occurs when surface water runoff concentrates in specific paths, cutting deep channels into the soil. These channels enlarge over time, fragmenting the land into ravines. Because the channels are too deep to be smoothed over by normal tillage operations, the land becomes physically uncultivable and is rendered unusable for farming. The "badland topography" (e.g., Chambal ravines) is a result of severe gully erosion.
- Sheet Erosion: This involves the uniform removal of a thin layer of topsoil over a large area. It is often unnoticeable to the naked eye and does not result in the formation of channels.
- Rill Erosion: This is an intermediate stage where small, finger-like grooves form on the soil surface. Unlike gullies, rills are shallow and can be removed or leveled by standard agricultural ploughing.
- Wind Erosion: This refers to the detachment and transportation of soil particles by wind, prevalent in arid and semi-arid regions. It does not create the deep water-cut channels described in the question.
Key Takeaway: Gully erosion is an advanced form of water erosion characterized by the formation of deep, wide channels that permanently degrade land topography, making agricultural operations impossible.