Best known for platinum records in the early 2000s that put a techno sheen on blues and soul, the 49-year-old is taking on the drought-stricken state’s $46.4 billion agriculture industry with a petition calling for restrictions on how much water farmers may use. Even with his pop-chart reign long over, Moby commands more than 1 million Twitter followers and has inserted himself in the middle of one of California’s most heated policy debates in decades.