Give a geographical reason for each of the following:

(i) The colour of alluvium varies in different areas.

(ii) Khadar is more fertile than bhangar soil.

(iii) Black soil has a kind of self-ploughing characteristic.

(i) The colour of alluvium varies in different areas because its shades depend on the depth of deposition, the texture of the materials and the time taken for maturity.

(ii) Khadar is more fertile than bhangar soil as new layers are deposited year after year during monsoon floods.

(iii) Black soil has a kind of self-ploughing characteristic because during dry season, it shrinks and develops big cracks which help in air circulation. This characteristic causes a kind of self-ploughing.