The student pilot was instructed to move the fuel selector from the right tank to the left tank. When the airplane was on the downwind leg for landing, the instructor told the pilot to reduce power and perform a simulated forced landing. Because the airplane was far from the runway and 200 feet above the ground, the instructor told the pilot to go around. The student advanced the throttle, but the engine did not respond. The instructor took control of the airplane, turned 40 degrees to the right, lowered the landing gear, and made an off-airport landing on a rough dirt field. The left wing struck a large bush and was substantially damaged, and the airplane spun around 90 degrees to the left and slid sideways for about 65 feet. After evacuating the airplane, the instructor returned to turn off the electronics and noticed that the fuel selector was in the OFF position.