MADISON, Wis. — School boards and local governments across Wisconsin are rushing to reach agreements with unions before a new law takes effect and erases their ability to collectively bargain over nearly all issues other than minimal salary increases.

The law doesn’t go into effect until the day after Secretary of State Doug La Follette publishes it and it doesn’t supersede contracts already in place, fueling unions’ desire to reach new deals quickly. La Follette said that he will delay publication until the latest day possible, March 25, to give local governments as much time as possible to reach agreements.

Republican Gov. Scott Walker had asked La Follette to publish the law Monday, but the Democratic secretary of state said he didn’t see any emergency that warranted him doing so. La Follette opposed the bill and said he sat in his office watching parts of a weekend protest that brought as many as 100,000 people out in opposition to the law.

“This is the biggest change in Wisconsin labor management history in 50 years,” La Follette said, describing his reasoning for holding off on its enactment.

The law ends collective bargaining for public workers over everything except salary increases no greater than inflation.

It also forces state workers to make benefit concessions that amount to an 8 percent pay cut on average.

Walker also is proposing a nearly $1 billion cut in aid to schools in his two-year budget plan that would take effect in July.

The Wisconsin Association of School Boards is telling districts to be cautious about approving contracts that will make it more difficult for them to handle the cuts in aid Walker is seeking. Since Walker unveiled the bill on Feb. 11, between 50 and 100 of the state’s 424 districts have approved deals with unions, said Bob Butler, an attorney with the association.

The vast majority of them included benefit concessions consistent with what Walker proposed under the new law, Butler said.