Progress report for the first quarter of the 2019/2020 project yearThe purpose of the project is to develop new guidelines for restoring root health and improving overall tree nutrition for Florida oranges and grapefruit. The objectives of the project are to:1. Determine optimal nutrient concentrations in roots and leaves for multiple grapefruit and orange varieties.2. Compare and contrast fertigation, soil, and foliar fertilization to identify best application method for uptake of nutrients into both underground and aboveground components.3. Investigate the relationship between root and leaf nutrient contents to tree health, yield, and fruit quality as well as bacteria titer.4. Generate updated and new guidelines for optimal nutrient contents for roots and leaves for HLB-affected trees. Progress to date:The project is being conducted at three sites: Citrus Research and Education Center (CREC), Southern Gardens Citrus near Clewiston, FL and Indian River Research and Education Center (IRREC). Data collection continued in the first quarter of 2019/2020 particularly on soil, root and leaf nutrient concentrations, HLB disease ratings, tree physiological characteristics, and root growth and longevity. Data collection continues, and analyses will be done as more data is collected. First harvest of grapefruit was completed in Fort Pierce in January 2020 to determine fruit yield and juice quality. Root measurements, soil characterization, and canopy size determinations are completed every 6 months. Data analysis and comparison of early trends is under way. Early results show no significant differences in soil and tissue nutrient contents at the CREC and Clewiston sites for baseline samples collected in May 2019 but differences were observed in November 2019, where treatments providing 2x macronutrients and 2 to 4x micronutrients showed greater tissue and soil concentrations than standard practices but canopy size and yield did not differ across treatments in the first year. We will continue to monitor the trends over the coming months and report any observations accordingly. In terms of outreach, some of the project co-PIs, Dr. Rossi, Dr. Johnson, Dr. Ferrarezi and Dr. Kadyampakeni facilitated seminars at the Florida Citrus Show on January 22-23, 2020 in Fort Pierce, FL. Plans for Next QuarterThe team will continue with fertilizer treatments and data collection including yield and juice quality (at Lake Alfred and Clewiston sites), HLB rating assessments and root growth measurements and reporting on the progress of the project. Students working on the project will submit abstracts for presentation at the Florida State Horticultural Society Meeting in Sarasota, FL and the American Society of Horticultural Science in Orlando, FL.