Why it is important to characterize soil with such properties?

Yes. lack of biodiversity may result one species being dominant over the others, thus creating a bad difference on earth

example: the black plague of europe
cause: rats and rat fleas, mass execution of cats (which eats rats)
effects: rats and plague overpopulated thus resulting in loss of human lives.

Yes because there are friction when two things are rubed together

Nope but the rock has its own cycle.