You can't keep other candidates from 'poaching on your turf'. [=from trying to get voters who usually vote for you or your party to vote for them]
In chapter two, the author is on unfamiliar 'turf'. [=is dealing with an unfamiliar subject]
Synthetic 'turf' was installed in the playing field instead of grass.
(..) You better run for your lives. -Somebody call a cop! -He's psychotic! This is my territory. Understand? I never, ever want to see you on my turf again. Boo. Yeah! You the cat! Got my boy back! I did it! Give me some love! The plan worked! (..)2005 Madagascar