ST. LOUIS — The next farm bill is likely to be more about the present and less about the past, according to a U.S. Department of Agriculture economist.

Changing public attitudes are leading legislators to a change in how farmers are paid, according to Seth Meyer of the USDA’s Office of the Chief Economist. Meyer spoke at a meeting here sponsored by Rabo AgriFinance.

“This erosion of public support for decoupled payments is leading us to a farm bill that maybe has more coupled properties,” he said. “By coupled, I mean tied closer to production. With direct payments, you get those based on what you used to plant. Coupled payments are based more on what you are planting.”

Meyer, who recently joined USDA after a stint with the United Nations in Rome, pointed to a number of factors figuring into the negotiations in Congress over details of a farm bill. One is a desire by many politicians to make deep cuts in the program.

“Do you make those cuts in the farm bill now and pass them on? What’s the risk of making your cuts now? This is another context,” he said. “You’ve got these decoupled payments. Direct payments attract a lot of attention and become obvious targets for budget cuts in some people’s eyes.”

International trade agreements also come into play. Meyer pointed to a growth in the federal crop insurance program and a case filed by the World Trade Organization concerning cotton.

The proverbial 800-pound gorilla, however, remains the Supplemental Nutrition Assistance Program, formerly referred to as food stamps. SNAP comprises by far the biggest portion of farm bill expenditures.

The program has long been seen as necessary by farm-state legislators in order to gain approval by urban lawmakers for agricultural benefits including direct payments and crop insurance.

The $764 billion allotted for SNAP makes up 80 percent of the total farm bill expenditures of $973 billion over the past decade. By contrast, crop insurance expenditures were $84 billion, commodity payments were $59 billion and conservation was $62 billion.

Both the House and Senate have proposed cuts to SNAP, which accounted for about $75 billion of the 2012 budget. But the two sides are far apart on the numbers.

The House has proposed annual cuts of $40 billion, but the Senate bill includes only $4 billion in cuts. In addition, House Republicans are seeking to separate SNAP from the remainder of the farm bill.

“This is one of the sources of potential problems with getting this passed,” Meyer said. “The natural reaction is to say let’s meet in the middle and cut it by $22 billion. The problem is this is a rules-based program with a work requirement. That makes it very difficult to come to something in between. This is a gap that may be difficult to close.

“The House and Senate don’t have too many differences on where those expenditures are going to come from on the commodities side. But they have big differences about what to do about cutting food stamps in the Senate and in the House. A major reason for the stalling of a new farm bill has been the differences in proposed cuts to the program.”

Some groups have pushed for an extension of the farm bill.

“If there is one, producers will probably lose some amount of direct payments, and if you take a cut, maybe that’s the base you start from for further cuts,” Meyer said. “The crop insurance program is where the expenditures are. There’s some discussion about payment limitations on size. But what they’re talking about is actually enhancing this program in the new farm bill, not scaling it back.”