The intense smell of pot that usually blankets a popular quad at the University of Colorado-Boulder on April 20 was replaced by the smell of fish-based fertilizer Friday morning.

Administrators at the university had been planning this attempt to subdue one of the nation's largest annual campus celebrations of 4/20, beginning with a court case in which a judge ruled that the school could close its grounds to unauthorized visitors Friday. Officers will be checking every pedestrian and vehicle entering the school for IDs and anyone without a Buff One Card will be cordially told the campus is closed, CU spokesman Ryan Huff told The Denver Post.

Officers will also patrol campus, performing spot checks, although the police stressed they would not be profiling, and large highway signs have been placed to warn visitors that the campus is closed for the day.

We hope it's very peaceful, Huff told The Denver Post.

With over 30,000 students, CU was named the top party school in the nation in 2011 by Playboy magazine. According to a Reefer Madness list compiled by The Princeton Review, the college is also among the top schools for marijuana use.

After last year's gathering of over 10,000 people on the Norlin Quadrangle for a marijuana rally, campus officials decided to do everything possible to avoid a similar situation. A free concert will be held by Haitian-born hip-hop star Wyclef Jean coincidentally at 4:20 p.m.

Everything that we're doing today is to make it unpleasant to stand or sit or be on Norlin Quad, Huff told The Denver Post.

Anyone caught smoking on campus will be ticketed as usual, including anyone with a medical marijuana card that requires private use.

This is not about the war on drugs. It isn't even about marijuana use per se, university spokesman Bronson Hilliard told The Associated Press. Ten thousand to 12,000 (people) doing anything in the academic heart of the campus would be a problem.

Marijuana use has boomed in Colorado since voters approved medical marijuana in 2000. All marijuana is illegal under federal law, though Colorado will vote on legalizing it for recreational use for anyone over 21 this November.

A rally is also planned near the capitol in Denver Friday and Saturday. According to The AP, police have suggested they will take a hands-off approach to the gathering, which is expected to draw tens of thousands of people.