In 2022, state funding made it possible for the UF/IFAS Nutrient Management Program (NMP) to begin scrutinizing long-established fertilization rates for 14 crops to determine whether updates are needed. The goal was to pinpoint the appropriate amount of fertilizer to achieve optimum yield for each crop without posing harm to the environment. To that end, more than 60 scientists commenced 19 research projects across the state.

But it takes years of crop growth trials with calibrated adjustments for different variables to validate results and identify appropriate nutrient rates, said Michael Dukes, interim director of the program.

“We’ve been consumed with ramping things up, establishing relationships with growers, buying equipment and conducting the research,” Dukes said. “Now, we’re at a point where we’re seeing results.”

NMP scientists are honing application rates for nitrogen, phosphorus and potassium. Past recommendations for those key macronutrients needed updating to represent current production systems as well as to account for Florida’s varied environmental conditions, including diverse soil types ranging from sand to muck, or its hardiness zones, which range from 8b to 11b.

Growers have long known changes were needed to accommodate these realities, and the work of the NMP is welcome, said Bob Hochmuth, an NMP project leader and the assistant director of the UF/IFAS North Florida Research and Education Center–Suwannee Valley, where 15 of the scientists work.

The new rates are based on research that considers a farm’s location, as well as modern farming methods regarding row spacing, irrigation practices and seed varieties. They are derived from research that incorporates the use of technology to increase efficiency and decrease fertilizer leaching, including controlled-release fertilizers and precision application machinery that places nutrients directly at plant root systems rather than widely broadcasting it. They also consider that growers may be increasing the number of plants grown on their land to boost crop yield.

“It’s important that the new nutrient rates reflect changing cultural practices on farms,” Hochmuth said.

The UF/IFAS Plant Nutrient Oversight Committee (PNOC) reviews all nutrient rate research results for consistency and scientific integrity. The members are composed of administration and researchers with a background in crop nutrient management. They evaluate nutrient recommendation proposals for changes and vote to approve, deny or return them for revisions.

To promote transparency and ensure stakeholders understand and support the new rates, UF/IFAS is conducting outreach to growers, state agencies and advocacy groups. Stakeholders are learning about the research through a seminar series and by attending field days at locations where trials are underway. Advisory committees for specific crops allow growers to share input.

UF/IFAS also conducts research on private farms with private machinery, ensuring real-world conditions. In addition to engaging growers and making it possible to share new practices, this approach supplements research conducted under highly controlled conditions at UF/IFAS research and education centers.

“Whether it’s the farmers or the non-farm community, we’re trying to make sure that everybody is aware of what we’re doing,” Hochmuth said.

Although the state legislature has funded the NMP through fiscal year 2024-2025, ever-changing environmental conditions and production systems mean the scientists’ work will never truly end, Dukes said. Their research helps ensure Florida crops worth millions of dollars continue to thrive and support a key component of Florida’s economy.

“There is a huge economic benefit to society for us to do this research, so growers can continue to feed the world using fertilizer rate guidance they can trust while we are mindful about limiting nutrient loss to the environment,” he said.