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 Scythians used scorched-earth methods against King Darius the Great of Persia, during his European Scythian campaign. The Scythians, who were nomadic herders, evaded the Persians and retreated into the depths of the Steppes, destroying food supplies and poisoning wells. Many of Darius' troops died from starvation and dehydration.