For the first time in more than a decade, the Florida Legislature is considering reforms to a landmark law that grants roughly $745 million a year in tax breaks on farmland.

Sen. Steve Geller, a Hallandale Beach Democrat, and Rep. Juan Zapata, a Miami Republican, are pushing bills aimed at stopping developers from abusing the 1959 ''greenbelt'' law.

The law was intended to help farmers stay in business by reducing their property taxes. But many developers keep cows or crops on their land in order to win the same tax benefits.

''It bothers me when developers are calling Hertz rent-a-cow,'' said Geller, the Senate's Democratic leader. ``There comes a time when the land is no longer agricultural, and the landowners are just trying to avoid paying taxes.''

Other taxpayers have to pick up the slack, or less money is available for schools, public safety and other government services.

A Miami Herald investigation last year found that the Broward and Miami-Dade landowners claiming the biggest agricultural tax breaks are developers and land speculators. The Herald report found cows grazing on developer-owned properties strewn with rocks, trash, melaleuca and even construction equipment.

CURRENT LAW

Colleen Boggs, chairwoman of the Miami-Dade Agricultural Practices committee and a tropical fruit nursery owner, said the current law already allows property appraisers to strip agricultural tax breaks from sham farms. She said struggling farmers should be allowed to seek development permits that increase their land's value.

''A farmer needs options,'' she said. ``He shouldn't be punished for preparing for a time before it actually happens. . . . I'm afraid of a new law.''

Farmland preservation advocates say farmers can't have it both ways, getting the tax break while they're in business and while they're getting out of it.

Most states that grant tax breaks on farmland insist that landowners tend a certain number of acres, turn a profit, promise not to build, or pay back taxes when they do. Neither bill in Tallahassee includes these requirements.

Under the House bill, property owners would lose agricultural tax breaks after requesting ''government approvals or authorizations . . . that demonstrate an intent to change the land use in the immediate future.'' That means a landowner who applies for a subdivision plat, water or sewer services, or land-use change.

The Senate bill would allow landowners to continue receiving agricultural tax breaks during the early stages of development, until the building permits are issued.

''From a conservation perspective, we prefer the House bill, because it limits the amount of time a developer can take advantage of a farmland program,'' said Ben Kurtzman, legislative specialist for the Washington-based American Farmland Trust.

''I don't think the Senate bill does much of anything, and it may make it worse,'' said Janet Bowman, legal director for 1000 Friends of Florida, a growth management group in Tallahassee. ``Usually the building permit is the last thing a landowner applies for.''

NEGOTIATIONS

Geller said he is negotiating with agricultural leaders over the bill's wording. He also is trying to pacify some senators on the agricultural committee, who balked at the notion of reforms during an October meeting.

Zapata, who serves on the House agricultural committee, is braced for a fight during the annual legislative session, which begins Tuesday.

''The industry knows there are abuses and they're willing to ignore them, which is irresponsible,'' he said. ``I'd like to hear how they justify that.''