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
On 24 February 1917, the German army made a strategic scorched-earth withdrawal from the Somme battlefield to the prepared fortifications of the Hindenburg Line, thereby shortening the front line they had to occupy. Since a scorched-earth campaign requires that there be a war of movement, World War I provided little opportunity in general for this policy as it was a stalemated war fought mostly in the same concentrated area for its entire duration.