As the Senate debates the farm bill this week, a once-every-five-years lobbying extravaganza that sets policy on farm subsidies, food assistance, nutrition, and myriad other agricultural programs, here's a quick look at some of the big money interests that are involved, as well as pressure points for transparency, or the lack of it.

The money. Agribusiness has already sunk $39.2 million in direct contributions to federal candidate and party coffers this election cycle, nearly three-fourths of that to Republican interests, according to the Center for Responsive Politics. In 2008, the last presidential election cycle, which also happened to ...