Police suspect that Sam Samella is growing marijuana in a re…

Police suspect that Sam Samella is growing marijuana in a remote field on his farm. Samella has a barbed-wire fence posted around the entire 50-acre farm, pit bulls patrolling the fence perimeter, and “No Trespassing—And I Mean It” signs every five feet. Nonetheless, the police cut through the fence and enter the field, where they find the marijuana. Has there been a search under the Fourth Amendment?