BOULDER, Colo. (AP) — Stinky fish fertilizer and two dozen law-enforcement officers kept pot smokers away from a grassy quad at the University of Colorado on Friday, but a few hundred protesters defied the crackdown and rallied on another field, where some lit up at 4:20 p.m.

It was a far cry from last year’s April 20 pot celebration, when more than 10,000 people gathered on the university’s Norlin Quadrangle for the annual ritual of enjoying a smoke and demonstrating for legalizing marijuana.

That made the university the scene of one of the largest campus celebrations of cannabis in the nation — a reputation that prompted university administrators to take extraordinary steps to stamp out this year’s rally.

They banned unauthorized visitors from campus, and spread smelly fertilizer on the Norlin Quad and declared it off-limits. They even booked Haitian-born hip-hop star Wyclef Jean for a free concert timed to coincide with the traditional 4:20 p.m. pot gathering.

Still, they were only partially successful. A few dozen protesters veered off a sidewalk bordering the university on Friday afternoon and marched through campus, holding signs and chanting, “Roll it. Smoke it. Legalize it.”