Willie Nelson and John Mellencamp joined New York mayor Michael Bloomberg and a host of local farmers today (June 11) amid the Union Square Green Market to announce a Sept. 9 date for the annual Farm Aid benefit at Randall's Island. As usual, the artists will be joined by fellow Farm Aid board members Neil Young and Dave Matthews at the event.

"This will be the first Farm Aid that provides 100% homegrown food at the concert," Mellencamp said proudly. Acknowledging the organic market just a few hundred feet away, Nelson said, "This is a great example of what can be done in the big cities."

Farm Aid, which is now in its 22nd year, will dovetail with a new biofuel initiative in New York. Beginning next summer, 30% of the city's heating oil purchases will be required to contain 5% biofuel, with a goal of reducing greenhouse gas emissions by 30% by 2030.

Nelson was one of the first biofuel champions in the music world and recalled being puzzled when his wife first told him she was interested in purchasing a biofuel-compatible Volkswagen Jetta. "I thought she might have finally found my Maui stash," he joked, to uproarious applause. "[Biodisel] is the future. There's a huge demand out there -- now we need to increase the supply."

Bloomberg, who joked that he'd written a song called "Mamas, Don't Let Your Babies Grow Up To Be Mayors" with Mellencamp and Nelson on the latter's tour bus, said the September concert is expected to infuse $13 million into the city's econmony.

Backstage after the press conference, Mellencamp told Billboard.biz that although Farm Aid still has major hurdles to clear in its efforts to aid family farmers, he is touched by what has been accomplished so far.

"The most amazing thing I've ever seen was when [family farms] were hit really bad [in the early '90s]," he recalled. "We were able to provide mental health services for farmers who were on the verge of suicide; a phone call, or a couple of counseling sessions. I've had people tell me that without Farm Aid, they would have killed themselves."