From the Sacramento Bee:

For years, legalization advocates have argued that marijuana is America's leading cash crop, outranking corn, wheat, soy and a host of other heartland staples produced on an industrial scale.

Bringing pot production above ground, the argument goes, could produce a $30 billion tax bonanza for cash-strapped governments and a huge savings for law enforcement and prisons.

For more, see: California’s growing marijuana business impacting agriculture)

But new research dumps cold water on many of these claims, concluding that far from being America's biggest cash crop, marijuana probably isn't even in the top five. Rather, marijuana might make the top 15, "ranking somewhere between almonds and hay and perhaps closest to potatoes and grapes," the researchers say.

These findings are part of a new book, "Marijuana Legalization: What Everyone Needs to Know," by a team of researchers and public policy experts from Carnegie Mellon University, Pepperdine University, UCLA and the RAND Corp.

In particular, the authors take aim at a widely cited 2006 report by Jon Gettman, a former director of the National Organization for the Reform of Marijuana Laws, that valued America's annual marijuana production at a whopping $35.8 billion.

For more, see: New book discounts theory of marijuana as top US cash crop