Rubbing dirt on hands scene in Gladiator

In her book Gladiator and Contemporary Society, University of New Mexico Professor of Classics Monica S. Cyrino writes:

When Marcus Aurelius asks Maximus after the battle in Germania: "Tell
me about your home," Maximus delivers a sentimental speech about the
simple beauty and tranquillity of his farm, with its fecund soil
"black like my wife's hair." His wistful reverie evokes the modern
individual's yearning for the simplicity of the land. Russell Crowe
wrote this speech himself, drawing on his feelings of homesickness for
his own ranch: "That's the way I feel about missing my home too."

Marcus Aurelius tells Maximus that his home is "worth fighting for"
and thereby suggests that the protection of the small family farm is
one of the purposes of Roman military conquest. The old emperor, beset
by doubts about the legacy of his rule, has come to realize that the
countryside, not the city, is the true Rome. Maximus' speech
anticipates and fortifies his depiction as an old-fashioned man of the
land in the rest of the film, one who has been brutally displaced.
Maximus "has a farmer's vanity-free self-confidence." He picks up a
handful of dirt and smells it before each fight, drawing strength from
his connection to the soil. Franzoni explained why: "We wanted a
character trait that humanized the hero before battle ... Some thought
he did it when his life was in danger. But really, the impulse was,
he does it when he's about to kick ass." Maximus cannot lose as long
as he keeps in contact with the earth. (p.141)

David Franzoni was the screenwriter.