Young Dolph was tossing handfuls of a green, leafy substance out the window of his Lamborghini before getting pulled over, according to cops ... in a scene straight out of "Super Troopers."

Law enforcement sources tell TMZ ... Young Dolph was cruising around Fairburn, GA Thursday morning when a patrol car noticed the paper license plate on the rapper's yellow Lambo SUV was expired.

We're told officers lit him up, but Dolph continued driving for several blocks and that's when police noticed him tossing something green and leafy out the driver's side window.

In video from the traffic stop ... you see Young Dolph on his knees and in handcuffs as he's being detained by cops.

Our sources say police searched the Lambo but did not find any drugs, guns or contraband ... so Dolph was ticketed for littering and driving with an expired tag. He was not arrested.

We're told cops couldn't determine if Young Dolph was dumping marijuana out of his whip because the green substance was too scattered about the busy road by the time police pulled him over.