When David Bowie went through his R.-and-B. phase, they called it plastic soul. Now Neil Young is playing with the guys from Booker T. and the MGs, singing melodies ripped from the Otis Redding playbook, adding his own ragged guitar solos and flower-child lyrics: call it all-natural gra-soul-a. It's nearly always a little too sweet, with Young's voice reaching high to deliver heartfelt avowals of love tinged with sadness at the state of the world. A tightly professional backup of organ, mid-tempo drums and precise rhythm guitar keeps him from getting too wild and loose. But most songs go on for too long, and the rare tracks where he lets a little anger creep in, like Let's Roll, his homage to the Sept. 11 passengers of Flight 93, come as a welcome change. Too much sugar damages any dish, whether it's rock or soul.