Through a series of tax credits and bonds for farmers, Finance Committee Chairman Max Baucus, D-Mont., said Tuesday that he will be able to add up to $10 billion to the five-year farm bill now in development in the Agriculture Committee.

But Agriculture Committee Chairman Tom Harkin, D-Iowa, said he has seen little in the Baucus proposal that would provide real money to expand the farm bill’s bottom line, which is constrained by budget limits this year. Lawmakers can spend up to $20 billion above the bill’s approximately $280 billion baseline, but only if the added spending is offset.

The House passed its farm bill (HR 2419) on July 27. Baucus and Harkin both plan committee action on their version this month. Majority Leader Harry Reid, D-Nev., said this week that a farm bill or extension of existing law must be enacted by early October.

Baucus’ bill would include a new category of tax credit bonds for rural development projects, and would allow farmers to opt out of conservation payments in return for a tax credit. Among other things, the bill would authorize tax incentives to encourage farmers to grow crops that are used to make alternative energy.

Converting payment programs to tax credits would free up funds that in the past had to come from the farm bill’s baseline for other programs, according to a Baucus aide.

Baucus’ proposal also will include a permanent farm aid trust fund that will help farmers who lose livestock and crops to natural disasters. Some estimates peg the cost of the program at $5 or $6 billion over five years.