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Adopting seasonal fertilizer blackout periods 


Adopting seasonal fertilizer blackout periods 

Illustration by Christopher Ryan

To curb eutrophication and fish kills in Florida water bodies, every county and municipality may adopt a lawn and landscape fertilizer ordinance. Most ordinances are structured after a state model, specifying setback distances from water bodies, fertilizer rate limits, and training, licensing and enforcement.

One controversial section of the state model refers to prohibited application periods, with many adopted ordinances banning the application of nitrogen or phosphorus during summer (“fertilizer blackout period”). Turfgrass scientists argue that summer growing periods exhibit the least leaching, but environmental groups fear heavy rains will wash away applied fertilizer before it is taken up. These differing stances have led to protests and allegations of corruption.

To contextualize this issue, Florida decision-makers (those involved in policy creation) and residents were surveyed to determine lawn care maintenance practices, sentiments surrounding turfgrass, trust in landscape science, awareness of local policy, and personal variables, such as education and political affiliation.

The decision-makers were more likely to use automated irrigation systems and hand-pull weeds, and less likely to fertilize their lawns. No differences were found between populations in their neutral sentiments surrounding turfgrass, though the decision-makers were more likely to trust landscape science. Only 31.5% of Florida resident respondents could identify their local blackout policy, compared with 80.5% of decision-maker respondents.

Encouraging civic science programs regarding fertilizer may be an effective way to reduce controversy and alter the relationships among scientists, citizens and decision-makers.

Christopher D. Ryan; Kevin E. Kenworthy, Ph.D.; Alexa J. Lamm, Ph.D.; Laurie E. Trenholm, Ph.D; and John Erickson, Ph.D., University of Florida, Gainesville; and J. Bryan Unruh, Ph.D., University of Florida, Jay

Editor’s note: Earlier versions of these summaries were published in the 2016 ASA-CSSA-SSSA Meeting Abstracts, ASA, CSSA and SSSA, Madison, Wis.

Teresa Carson is GCM’s science editor.