Question

what are the factors responsible for crop depletion

Answer 1

This is the removal of the topmost soil by either water or wind. When the topmost soil is taken away, it exposes the layer beneath for further loss, as nutrients are taken away as the topmost soil is removed.

Answer 2

How the Factors Cause Depletion of Soil Resources
Soil erosion:
This is the removal of the topmost soil by either water or wind. When the topmost soil is taken away, it exposes the layer beneath for further loss, as nutrients are taken away as the topmost soil is removed.