Water quality and quantity are issues that cross all political and economic boundaries in Florida. When blue-green algae and red tides occur, they make front-page news and keep these challenges top-of-mind for all Floridians.

Agriculture and the water quality debate have been closely intertwined over the years. As a large user of water for irrigation and the need to fertilize crops to make them productive, growers often get singled out in the debate. But growers have been proactive in the process and have worked to be a part of the solution to water issues.

This article was first printed in the November 2023 edition of Florida Grower magazine, written by Frank Giles, editor-in-chief. It is reprinted here with the permission of AgNet Media.

Building Better BMPs

During the 2022 Florida legislative session, SB 1000 was passed and signed into law. The bill allocated $8.8 million in funding to the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) to update fertilizer recommendations for key crops in the state. The revised recommendations will be the foundation for new best management practices (BMPs) updates from the Florida Department of Agriculture and Consumer Services (FDACS).

Work is well underway, according to Thomas Obreza, director of the UF/IFAS Nutrient Management Program. He is leading the project to update nutrient recommendations and says it is important to clearly define BMPs and UF/IFAS recommendations.

“UF/IFAS nutrient management recommendations are proposed by faculty after they conduct scientific trials at our research and education centers and on Florida growers’ fields,” Obreza says. “The UF/IFAS Plant Nutrient Oversight Committee reviews the researchers’ results and takes public comments before approving new recommendations. Once accepted, UF/IFAS maintains the recommendations and shares them with producers.

“The term ‘BMP’ can be used a couple of ways, one being generic and the other tied to the FDACS program administered by the Office of Agricultural Water Policy designed to allow for normal agricultural production while also protecting water resources. It is up to FDACS to determine what practices they accept as BMPs. In some cases, FDACS BMP manuals (e.g., sod) point directly to the UF/IFAS recommendation as the BMP. In other cases, the tie between the UF/IFAS recommendation and the BMP is less well-defined.”

By rule, UF/IFAS develops recommendations, while FDACS develops and adopts BMPs. SB 1000 calls for “recommendations on BMPs for supplying fertilizer to the crop to achieve maximum crop yield and quality goals of the grower while doing so in a manner that minimizes nutrient inefficiencies to the environment.”

Obreza says current UF/IFAS nutrient research is in line with that language in the law.

There are several crops now being studied for nutrient recommendation updates. Obreza says the two crops initially getting the most attention for possible updated recommendations are tomato and potato because they have been studied the longest to date. Research is turning up some interesting results.

“The most interesting thing we are seeing is how vegetable crops are responding to soil phosphorus as measured by the standard UF/IFAS soil test,” Obreza says. “We are learning how the current ‘critical value’ of soil test for phosphorus lines up with crop response. We will adjust the calibration if our data shows the need. It has also been interesting to see positive responses of row crops like corn to enhanced efficiency nitrogen fertilizer. And we are also not surprised to see that water management is key in nutrient management.”

The water management aspect is critically important. Although the legislative language specifies fertilizer rate study, UF/IFAS is researching nutrient management using the “4Rs Plus One” concept. The 4Rs stand for right rate, right source, right timing, and right placement.

“The ‘Plus One’ is right water, which is very important in Florida,” Obreza says. “Irrigation and nutrient management go together, so we’ve dedicated research in this area, too.

“We also want to acknowledge the tremendous support we are getting from grower-cooperators who are hosting a lot of our research on their farms and the Florida Legislature for providing the funding that allows us to do the work.”

You can read the rest of the Florida Grower article HERE.

The article was posted on the UF/IFAS Nutrient Management Program Blog by Mike Loizzo.

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