It would be a case for introducing the very French notion of "terroir", often used about wine of course, but not only (la France et ses terroirs, un homme du terroir, etc.). Maybe: "prondément enraciné dans son terroir (natal)", or, if you don't use this word (which implies he/she was born there anyway, more or less...), "profondément enraciné dans sa région d'origine". I would avoid the word "sol", here ("le sol" = the ground, the floor), since it does not really encapsulate the idea of "soil", I feel. "Terroir" of course sounds a bit rustic. It would be odd if used in connection with someone who, say, comes from a large city such as LA or Paris!