Crows in Vegetable Garden

Got a call from a "Plant a Row for the Hungry" garden group. They have standard southern garden stuff...tomatoes, corn, watermelons etc and are having a bad time with crows. It is right beside a large church/school so that potentially complicates matters. I am not a bird expert. Any suggestions? Garden is maybe 1.5 acres.

motion activated sprinklers, not the watering kind, the knock down kind. heavy stream of water.

Did they try a scare crow . I got some crows been messing in my garden been letting them be but there really pushing it .they even look at my corn it's on im building a big demon looking scare crow .Seems like you could cage trap them with corn. Suckers might get smart quick very smart bird .

In the million or so years that I have been trapping, I managed to catch exactly one crow in a cage. ( And the rest of the crows in the area applauded loudly that his genes weren't being passed on ) Does anyone actually catch a reasonable amount a crows in an kind of device?