Nutrition Findings for Florida Citrus

Florida’s Citrus Nutrition Box Program that began in the fall of 2019 has shown that regional differences occur around the state with secondary macronutrients and micronutrients. It also showed that manganese and zinc are a concern for almost all areas. Jamie Burrow presented those findings, and numerous others, as part of Citrus Nutrition Day in October at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education Center (CREC). Burrow is a UF/IFAS Extension program manager at the CREC in Lake Alfred.

A few other key messages from the presentation, which focused on HLB-affected trees, include:

• A soil pH between 5.8 and 6.5 is best for HLB-affected trees. That level is ideal for all nutrients and allows well-balanced nutrient uptake.

• The program found a need to apply higher rates of manganese than were previously recommended for healthy trees.

• Statewide, calcium levels decreased over the year to below optimum; they typically increase over the year in healthy trees. Thirty-five percent of trees in the project were low in calcium.

• Most nutrients stayed in the optimum range throughout the year.

• HLB-affected trees used nutrients quicker than healthy trees; their smaller root systems need a constant supply to meet nutritional needs.

The Nutrition Box Program’s objective is to help growers implement research findings though a collaborative project with UF/IFAS. Through the program, participating growers collect quarterly leaf samples and annual soil samples, which they send to a lab. UF/IFAS experts review the results and send recommendations to the participating growers. From October 2019 to February 2021, 258 leaf samples and 81 soil samples were collected from 19 counties as part of the program.

Burrow’s full presentation contained much detailed information regarding specific nutrients in different Florida citrus-growing regions.

Other Citrus Industry articles about Nutrition Day addressed fertilization methods, nutrition and yield and how HLB changed UF/IFAS recommendations.