what does the dirt mean from the movie " Gladiator" ?

Regarding with the meaning "the dirt" from "Gladiator",
I think the General Maximus picking up the dirt is a kind of sign or habit and
make a decision.
Before being the General, he's been a farmer in Spain.
So he is familiar with the black earth.

Probably he always picks up the it before he makes an action.
And also he is always missing his hometown hoping to go back.
After the battle ends, he will be back to his home.e never forget his lovely family,home and all about thing in Spain.
Especially he likes the black earth.