DES MOINES — Leaders of the split-control Legislature on Wednesday were negotiating the framework of an initial budget deal that could resolve tax policy and school funding issues that are major sticking points holding up progress on this year’s session work. Sen. Joe Bolkcom, D-Iowa City, chairman of the Senate Ways and Means Committee, said the tax-policy compromise (Senate Study Bill 3171) called for adopting a measure passed by the Iowa House to fully couple federal income tax changes to the state tax code retroactive to the 2015 tax year and adopt a scaled-back version of state sales tax breaks on consumable supplies used in the manufacturing process. The coupling piece would provide up to $95 million in tax relief while the manufacturing sales tax changes would total “in the neighborhood of $25 million,” Bolkcom said.