Imagine a root of a cotton plant growing in the upper horizon of an irrigated soil in california's imperial valley. as the root attempts to draw water molecules from this soil what forces (potentials) must it overcome? if this soil were compacted by a heavy vehicle, which of these forces would be most affected?

A root of a cotton plant must overcome various potential forces such as gravitational forces that pulls water downward, matric forces where there is an adhesion of water molecules from a soil and osmotic forces where attracting water in the presence of large amount of soluble salts in the mixture of soil.

If the soil were compacted by a heavy vehicle, the matric forces would be mostly affected for compaction will result to increase matric forces due to reduced size of pores of the soil making it more difficult to draw water from a solid surface.