The farm bill has hit a major stumbling block in the Senate as the two parties feud over what amendments to take up. Ag Chair Stabenow is downplaying the fight - but concedes it’s impeding the bill for now. Getting a farm bill done this month in the Senate just got a lot tougher. GOP Leader Mitch McConnell wants his side to be able to offer its amendments to limit agency rulemaking that impacts agriculture and some unrelated amendments. Majority Leader Harry Reid says no and has shut down an open amendment process after the GOP withheld unanimous consent to move forward. Stabenow…