Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: Equilibrium water content in soil at a certain matric potential is higher when the soil is under drying process (desorption) compared to when the soil is under wetting process (sorption).
Reason R: Contact angle between water and the soil solid phase is greater during imbibition of water than during drainage.
In light of the above statements, choose the most appropriate answer from the options given below:

Correct option is A

The hysteresis phenomenon in soil water retention explains why soils retain more water during desorption than during sorption at the same matric potential. This is partly due to changes in the contact angle, which is greater during wetting (imbibition), thereby affecting water adhesion. Hence, both A and R are correct, and R correctly explains A.