The 20th annual Farm Aid concert will be staged in Hershey, PA's Hershey Stadium on September 22 and will include performances by charter members Neil Young, John Mellencamp, Willie Nelson and Dave Matthews, joined byTim Reynolds, Jack Johnson, ALO, Pegi Young & The Survivors and Lukas Nelson & Promise of the Real. The series has generated more than $40 million in assistance to family and small farms during its two decade run.  Dave Matthews talks about the importance of the cause in a promotional video.