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.
(..) up for you guys after /. And what did you do, um, what did you do after the invasion? Before you went back to Pesh? After /, we had to choose. Fight to protect our turf or run. And you chose to fight, yeah? We wanted to kill Americans. Yeah. We tried to get into Tora Bora, but the (..)2012 Zero Dark Thirty