Question 29
What happens when rain falls on soil without vegetational cover?

(a) Rainwater percolates in soil efficiently
(b) Rainwater causes loss of surface soil
(c) Rainwater leads to fertility of the soil
(d) Rainwater does not cause any change in soil

(b) Rainwater causes loss of surface soil

Infiltration depends on there being sufficient porosity in the surface soil for rainfall to infiltrate, and in the subsoil and parent material (if shallow) for rainwater to percolate. When the porosity of the surface soil is too low to accept rainfall or subsoil porosity is too low to allow rainwater percolation (i.e. permeability is too slow), then infiltration will be restricted and rainwater will be lost as runoff.