By: Kelly Aue

LIVE OAK, Fla. — In the Suwannee Valley, farmers are diligently searching for solutions, or Best Management Practices (BMPs), to efficiently use fertilizers in crop production. At the UF/IFAS North Florida Research and Education Center – Suwannee Valley (UF/IFAS NFREC-SV), a team led by Bob Hochmuth, UF/IFAS Extension regional specialized agent for vegetable crops and assistant center director, has been researching the use of controlled release fertilizers as an advanced BMP.

“While controlled release fertilizers have been around for years, the technology has improved through research discoveries over the past three years,” Hochmuth said. “The research has shown very encouraging results in growing the corn, carrot and watermelon crops important to this region. Controlled release fertilizers have obtained the same yield and quality compared to conventional fertilizers. In many cases, less nitrogen was applied.”

Controlled release fertilizers are typically applied once at the beginning of the season.

“In simplistic terms, the fertilizer granule is coated with a polymer-type material that protects the fertilizer and releases it over time depending on the type and thickness of the coating,” Hochmuth said. “The rate of release of the nutrients in the soil is usually dependent on temperature. The higher the temperature, the greater the release.”

This technology can now match the right rate release with the right crop and greatly reduces the risk of excess available nitrogen in the soil being leached below the active root zone of the crop.

In comparison, conventional fertilizers may require several applications with higher labor and fuel costs. While controlled release fertilizers are more expensive, with fewer trips across the field, it can reduce the overall cost. “If reduced rates can be proven to consistently perform equal to conventional fertilizer programs, this technology may become more commonly adopted by farmers resulting in reduced nitrogen losses,” Hochmuth said.

Finding new advanced BMPs for farmers is critical to the success of the Basin Management Action Plans (BMAPs). BMAPs set the path to improving water quality and quantity in the Suwannee Valley region and reducing nitrogen is one of the keys to meet its goals.

“Nitrogen is the nutrient of greatest concern because it is highly soluble and can move downward in the deep sandy soils in the region,” Hochmuth said. As one of the more limited nutrients in crop production in the region, the current BMPs suggest applying smaller amounts of nutrients several times over the course of the growing season. This makes the most efficient use of nitrogen and reduces the risk of heavy nitrogen loss during heavy rainfall.

Using more advanced BMPs, like controlled released fertilizers, new irrigation technology and soil moisture sensor technology, farmers can eliminate nitrogen leaching during irrigation events, produce high-quality yields, and increase crop nutrient efficiencies.

Continued research by UF/IFAS faculty will help discover new ways to utilize these advanced technologies and help reduce nitrogen losses in the field that could impact our region’s groundwater and surface water quality.

(Photo above: A corn field trial at UF/IFAS NFREC-SV tests different controlled release fertilizers. Credit: UF/IFAS)

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The mission of the University of Florida Institute of Food and Agricultural Sciences is to develop knowledge relevant to agricultural, human and natural resources and to make that knowledge available to sustain and enhance the quality of human life. With more than a dozen research facilities, 67 county Extension offices, and award-winning students and faculty in the UF College of Agricultural and Life Sciences, UF/IFAS works to bring science-based solutions to the state’s agricultural and natural resources industries, and all Florida residents. Visit the UF/IFAS website at ifas.ufl.edu and follow us on social media at @UF_IFAS.

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