Police say farmers should remain vigilant to music events taking place on their land, and the Country Land and Business Association (CLA) regional director, Robin Edwards, said: "We urge farmers and landowners to help the police by reporting any suspicious activity, as early intervention and good local intelligence can prevent these illegal events and organisers can be dealt with appropriately.
"Raves cause a great deal of disruption to communities and often result in damage being caused to property and land. Thames Valley Police's proactive approach to reducing raves is very welcome as landowners can fall victim, bearing the considerable clean-up costs incurred."
Organisers have to apply for a Public Entertainment Licence through the local council to hold music events, and applications are also scrutinised by the police and firefighters.
Superintendent Jim O'Ryan added: "We will take a robust line with illegal rave activity. Anyone considering holding or attending this type of event should reconsider their intentions carefully.
"We urge owners of land or buildings to take steps to prevent raves taking place there."
To report a rave, call 101 or Crimestoppers anonymously on 0800 555 111.