It's normal for suffixes to use either ON--yomi, but even for Japanese it's weird to use the ON-yomi AFTER the preposition の, because the の generally means whatever comes next is a separate, stand-alone word and not part of a jukugo. BUT NOT THIS TIME (BOOBOO)
Soldiers drunk-drive their car from the base to town and back, drinking GIN.
xxx's camp or base, usually but not always military
陣 (base) + 地 (area)
= 陣地 (territory)
This word used only during war (excuse me, during KINETIC OPERATIONS), and it means territory or positions held by a military force.