Scorched earth
A scorched-earth policy is a military strategy that aims to destroy anything that might be useful to the enemy while it is advancing through or withdrawing from a location. Any assets that could be used by the enemy may be targeted, for example food sources, water supplies, transportation, communications, industrial resources, and even the locale's people themselves.
Scorched earth
The concept of "scorched earth" is sometimes applied figuratively to the business world, where a firm facing a takeover attempt will make itself a lesser prize by selling off its assets.