TAMPA — The City Council is poised this week to take the first step toward giving Tampa one of Florida's most restrictive fertilizer sales laws.
As proposed, no fertilizer containing nitrogen or phosphorus could be sold or used on residential lawns during the summertime rainy season.
Currently, only Pinellas County and its myriad municipalities have such a ban. (In Hillsborough County, there's a ban on using fertilizer if heavy rain is in the forecast, but there is no ban on sales.)
From the perspective of the Tampa Bay Estuary Program, the proposed city ordinance would help keep Tampa Bay clear of nitrogen-fed algae blooms.
"It's good for the environment," and it doesn't mean homeowners can't have nice, well-cared-for lawns, said Holly Greening, the estuary program's executive director.
But from the viewpoint of the lawn care industry, a ban on nitrogen-based fertilizers would be an unproven and even counterproductive law.
"Well-intended, but misguided," said Allen Fugler, executive vice president of the Florida Pest Management Association. Such bans, he says, are not based on science, are not enforceable and can't be demonstrated to have any impact on water quality.
In the middle will be the Tampa City Council, which must decide whether to enact a ban — and soon. The council is scheduled to take a first vote on Thursday and a final vote on June 23.
Under a law passed this spring by the Legislature, the state will be responsible for regulating sales of fertilizer, except for cities and counties that have passed their own laws by July 1.
At stake for the city, proponents say, is money, and lots of it.
The U.S. Environmental Protection Agency and the Florida Department of Environmental Protection monitor the amount of nutrients such as nitrogen that flow into Tampa Bay.
Those levels currently meet state and federal standards, officials say, but they are expected to rise once the economy picks up, growth resumes and more people move into the area.
Then, officials say, local governments could face big fines for violating those limits.
"The city of Tampa is going to face an enormous problem just around the corner on the (maximum) loads of phosphorus and nitrogen that you can put in the bay," said City Council Chairman Charlie Miranda, the council's expert on water policy and a supporter of the proposed ban. "There is no benefit to us standing still."
Proponents of the law say it's more cost-effective to keep nitrogen out of the bay, the Hillsborough River or other lakes and streams than it is to remove it once it's there.
Removing a pound of nitrogen from the environment costs about $3,500, according to the estuary program.
The city of Tampa, along with a couple of state agencies, has one project under way to do this. The River Tower project will spend about $2.5 million to remove 696 pounds of nitrogen by diverting Sulphur Springs runoff to a new stormwater treatment pond.
Advocates of a summertime sales ban estimate that it would prevent 8 tons of nitrogen from getting into Tampa's waterways even if only half the city complied with the law.
That, they estimate, would save the city $56 million in removal costs.
Pinellas County officials say their ban is based on years of research, including:
•A 2009 study of the accumulation of muck in the Safety Harbor area of Tampa Bay. The University of South Florida College of Marine Science found evidence that Safety Harbor's sediment increasingly comes from nitrogen fertilizer, not the bay's own algae.
USF researchers reported finding "multiple lines of evidence" that Safety Harbor is at or near the point where nutrients are so rich that aquatic plants grow excessively, oxygen is sucked out of the water and fish choke.
The data suggest "this trend will continue if terrestrial sources of nutrients are not moderated," they wrote.
• A 2004 report prepared for Pinellas County and the Southwest Florida Water Management District by two environmental consulting firms, Leggette, Brashears & Graham and SDI Environmental.
This study concluded that 79 percent of the nitrogen in Lake Tarpon came from fertilizer, as opposed to animal waste or septic tanks.
Proponents say homeowners can use fertilizers containing iron or magnesium during the summer to keep their lawns green.
Opponents of a ban point to research from the University of Florida's Institute of Food and Agricultural Sciences (IFAS).
A 2009 review of scientific studies by these UF researchers found, among other things, that Pinellas County's study of Lake Tarpon did not determine whether the nitrogen there came from fertilizer that was improperly applied.
Looking at studies from around the country, the Gainesville researchers said that while algae blooms are a growing problem, unfertilized turf will be less dense, and thus more likely to allow runoff and nutrients to be washed away.
As an alternative, they recommended "best management" practices that include applying fertilizer according to manufacturers' instructions, keeping it off pavement and keeping grass clippings (another source of nitrogen) on lawns and out of streets and gutters.
These conclusions, however, do not come without a controversy of their own.
In October 2009, the St. Petersburg Times reported that IFAS had received at least $505,000 from the turf industry for research projects. The industry had requested that IFAS write the 2009 report, which was updated early this year, and provided half the funding for research that went into it.
In response, a UF researcher who had testified against summertime sales bans and had received $178,000 from the industry called questions about his impartiality "fighting words."
The turf industry says the IFAS research is peer-reviewed, making it credible and reliable.
Pass a ban, industry representatives predict, and some homeowners will end up with unhealthy yards that do not capture runoff, thus making the problem worse.
Others will simply ignore the ban.
"Prohibitions didn't work for liquor," said Mary Hartney, president of the Florida Fertilizer & Agrichemical Association. "I don't think they'll work for fertilizer, and I think you'll miss your opportunity to educate the public on how to do it right."