Maybe some pilot training.
I doubt that. My son is a helicopter pilot in the Army and they wouldn't train low over someone's rice field due to the air they force down would damage the rice.
A helicopter mashes air down. This is why rescue helicopters over water hover away from a small boat and drop a swimmer who swims over. If they hovered over the boat the downforce of the air under the helicopter would literally since the boat. It is that strong.
Of the helicopter was constantly moving then that would minimize the downforce effect. Could it have been spraying the crop for insects?
