Both the school football team and the marching band need practice, and they must share the same high school football field. A Funky Winkerbean newspaper comic strip by Tom Batiuk published on September 12, 1977, featured this three-panel joke:
 
Marching band leader (to high school football coach): WHAT DO YOU MEAN THE FOOTBALL TEAM NEEDS THE FIELD?
Marching band leader (to high school football coach): THE BAND IS PRACTICING NOW.
Marching band leader (to high school football coach): FOOTBALL FIELDS ARE FOR BAND PRACTICE!
 
Funky Winkerbean: Football Fields Are for Band Practice!! was the title of a 1986 book.
   
     
Wikipedia: Funky Winkerbean
Funky Winkerbean is a long-running comic strip by Tom Batiuk. Distributed by North America Syndicate, a division of King Features Syndicate, it appears in more than 400 newspapers worldwide.
 
While Batiuk was a 23-year-old middle school art teacher in Elyria, Ohio, he began drawing cartoons while supervising study hall. In 1970, his characters first appeared as a weekly panel, Rapping Around, on the teenage page of the Elyria Chronicle Telegram. In 1972, Batiuk reworked some of the characters into a daily strip, which he sold to Publishers-Hall Syndicate.
 
12 September 1977, The Jersey Journal (Jersey City, NJ), “Funky Winkerbean” comic strip by Tom Batiuk, pg. 22, col. 4:
Marching band leader (to high school football coach): WHAT DO YOU MEAN THE FOOTBALL TEAM NEEDS THE FIELD?
Marching band leader (to high school football coach): THE BAND IS PRACTICING NOW.
Marching band leader (to high school football coach): FOOTBALL FIELDS ARE FOR BAND PRACTICE!
 
OCLC WorldCat record
Funky Winkerbean : football fields are for band practice!!
Author: Tom Batiuk
Publisher: Wichita, KS : NLP Marketing, 1986.
Edition/Format:   Print book : English
     
13 July 1990, The Arizona Republic (Phoenix, AZ), “Through the tears, band played on for leader” by Bob Petrie, Northwest Community sec., pg. 6, col. 4:
Others talked of the jokes McCord (John McCord, chairman of Ironwood High School’s fine arts and music department—ed.) liked to tell—over and over—of his thirst for Diet Cokes and his fondness for the long-suffering high school band director in the comic strip “Funky Winkerbean.”
 
One of the strips panels on display among the memorabilia and awards McCord’s band teams have accumulated through the years depicted the band director asserting himself, saying, “Football fields are for band practice.”
 
Twitter
Cortana
@EmpressCortana
Replying to @allenmmurray
@allenmmurray Psh, football season? It’s Marching season. Football fields are for band practice.
8:17 PM - 3 Sep 2011
 
Twitter
Deniece Wood
@DenieceCWA
One of the most important lessons I learned in high school-FOOTBALL FIELDS ARE FOR BAND PRACTICE! Haha!
6:19 PM - 6 Oct 2014 from Boone, NC