WEST PALM BEACH, Fla. (AP) _ Sugar growers, the water district and the state of Florida have agreed to share the cost of a $120 million plan to clean up the Everglades and Lake Okeechobee.

Under the plan, approved Thursday by the South Florida Water Management District, about 74,000 acres of farmland are to be bought and converted into marshes to filter phosphorus-laden agricultural runoff blamed for much of the pollution plaguing the Lake Okeechobee-Everglades system.

Water flowing south from farm fields would be cleaned by running it through the marshes, where plants would absorb excess phosphorus blamed for upsetting the Everglades ecosystem.

''It's very historic that everybody came to the table and agreed to pay for this,'' said Ann Overton, a spokeswoman for the water district. ''It's a big step forward.''

Environmentalists involved in a 27-month effort to reach the accord criticized the sugar industry's $40 million share as too low.

And the question of whether the federal government will now drop a pollution lawsuit against the state and the water district remained unanswered.

The lawsuit, filed by Miami U.S. Attorney Dexter Lehtinen, contends water managers and the state allowed federal parks in the region to be degraded in violation of pollution laws and signed agreements.

In Washington, Justice Department spokeswoman Amy Casner said the government had no immediate comment on whether the plan was enough of a step forward for the federal government to drop the lawsuit.

On Tuesday, Gov. Bob Martinez worked out and approved the compromise, despite estimates that the cleanup could end up costing as much as $500 million.

''I think the majority of the industry decided that this may be as good as the deal was going to get. They'd better take it,'' said Andy Rackley, vice president of the Florida Sugar Cane League.

Under the plan, the Everglades cleanup area would be quadrupled, with the cost split into equal $40 million shares for the state government, the water district and sugar growers.

''I don't think that that necessarily represents a fair contribution from agriculture. It may be, but there are too many unknowns for us to be capping any contributor,'' said Doran Jason, a member of the water district's board.

Environmentalists agreed.

''You are making a statement that it is appropriate to allow an industry that is causing a number of environmental problems to pay something like 10 percent of the amount it will take to solve the problems,'' said Charles Lee, executive vice president of the Florida Audubon Society.