Officers from Devizes were called out to deal with the incident at around 10am after a member of the public spotted the shell.
Officers secured and cordoned off the area and called in the Explosive Ordnance Disposal Team (EOD) to carry out a controlled explosion.
Police said: “Our colleagues from the Explosive Ordnance Disposal Team safely detonated the bomb leaving nothing more than the hole in the farmer's field.”
To watch the explosion, go to https://www.facebook.com/Devizes-Police-646771368682921/videos/1031636113996663