Answer:
Water, carbon dioxide, and oxygen are among the few simple molecules that can cross the cell membrane by diffusion (or a type of diffusion known as osmosis ). Diffusion is one principle method of movement of substances within cells, as well as the method for essential small molecules to cross the cell membrane.
Consequently plant roots will get more moisture with less effort. It also improves soil structure due to alternate drying and cooling and soil aeration which helps in multiplication of micro-organisms. This is the reason that farmers plough their field during summer.
Hope this helps!
~ Kana ^^