IFAS ‘science’ protects lawns, not springs

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By Bob Palmer, Florida Springs Institute

For five years, researchers from UF’s Institute of Food and Agricultural Sciences have presented highly flawed recommendations to city and county commissions all over the state. Many commissions concluded that IFAS’s advice constituted “sound science” and voted accordingly, ignoring contradictory evidence from concerned citizens deemed less “scientific” than IFAS. However, it’s now apparent that IFAS’s positions are closer to junk science than sound science. And sadly, the upshot of heeding IFAS’s advice has been further degradation of already impaired springs, rivers, and estuaries.

The issue is lawn fertilizers, the stuff we spread in our pursuit of perfect greenness. Nitrogen fertilizers may help grass grow, but they also bleed into the environment, threatening our waterways with unwanted pollution and algal gunk.

Around 2005, the state provided IFAS with $4.2 million to determine the effectiveness of its lawn fertilizer recommendations – how much to apply and how and when to apply it. IFAS dean John Hayes expressed his hope that “our findings will play a substantial role in helping residents, industry, and policymakers protect water quality.” Unfortunately, it hasn’t worked out that way.

By 2012, IFAS representatives were popping up at county commission meetings describing lessons from the $4.2 million expenditure. A key issue, then and now, was the “summer ban” – whether local governments should outlaw summer application of lawn fertilizer because heavy summer rains might wash it into the aquifer or nearby water bodies.

IFAS representatives insisted that summer bans were counter-productive because grass is healthiest in the summer, when its robust roots will absorb any fertilizer before rains wash it away. That position was expressed clearly by IFAS fertilizer advocate Laurie Trenholm before the Brevard County Commission: “If we apply fertilizer to healthy turf at the recommended IFAS rate, we are going to see 99 point something percent of the nitrogen taken up by the turf …”

While some commissions, like Seminole County in February 2017, enacted a summer ban, others including Orange County in June bought the IFAS argument and rejected the summer ban.

IFAS’s recommendations are based not on the overall environmental impact of lawn fertilization but narrowly on measurements of nitrogen leaching through manicured IFAS research plots. It’s true that in some cases, little fertilizer was detected in water leaching through these plots.

However, those were selected cases. At a 2013 IFAS symposium highlighting results from the $4.2 million study, I saw many graphs and charts where nitrogen leaching greatly exceeded 1 percent.

But a far bigger problem with this research is that IFAS asked the wrong questions, leading to “results” which have no bearing whatsoever on environmental protection. The key question is “where does all this lawn fertilizer actually end up,” not “how much nitrogen leaches through soil under ideal conditions.” And fertilizer nitrogen can end up in a number of places besides leaching: in the grass itself, in soil, in run-off, into the air as nitrogen gas; or unchanged into the air via “volatilization”.

Chemical conversion of fertilizer to nitrogen gas is environmentally benign. Fertilizer which runs off or volatilizes into airborne urea is not benign.

IFAS never studied these other possible fertilizer destinations. Citing only its leaching data, IFAS routinely testified that 99-plus percent of the nitrogen was “taken up by turf.” The statement is patently false because IFAS never tracked how much nitrogen stayed in the soil, ran off into a nearby stream, or volatilized into the atmosphere and later came back down in rainfall.

Are these other paths for nitrogen inconsequential? I posed that question recently to Nick Place, IFAS extension dean, who replied that 1 to 60 percent of nitrogen applied to turf grass may volatilize and end up in the atmosphere. Place cited turf grass uptake rates of 25 to 74 percent and concluded that “…our faculty state that 100 percent uptake does not occur in any plant system … we are unaware that any IFAS researcher has stated 100 percent nitrogen uptake occurs in turf grass.

If that was stated, it was an inaccurate statement.” 

Maybe not 100 percent, but in fact, IFAS researchers have made the “99-plus percent” statement repeatedly to elected officials. IFAS’s arguments against a summer fertilizer ban are based on extrapolations far beyond what their limited science can support.

Elected officials need to know two things: Fertilizer applied to turf grass doesn’t remain there forever – it will end up in the environment eventually, wreaking ecological harm on impaired waters. And summer bans are more scientifically valid than IFAS’s recommendations and are a common sense approach to limiting the damage that lawn fertilization inevitably inflicts.


Bob Palmer lives in Gainesville and is a board member of the Florida Springs Institute.