Florida citrus growers hit hard by citrus greening can benefit from University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) expertise in an updated book — the third edition of the Nutrition of Florida Citrus Trees.
Greening, known scientifically as huanglongbing (HLB), has caused significant damage to Florida’s citrus industry. UF/IFAS scientists and Extension faculty have updated the guide to help farmers better cope with HLB.
Although the book still contains some data from the 2008 edition, that information remains sound for healthy trees, said Davie Kadyampakeni, assistant professor of soil and water sciences at the UF/IFAS Citrus Research and Education Center and co-editor of the latest nutrition guide.
The guide includes new information on the best ways to use soil organic matter, a product of residues from organisms that have decomposed and are incorporated in the soil. Using soil organic matter efficiently gets proper nutrients to greening-affected trees and improves their water use.
“Much of the information provided in this document on nutrients, application methods, leaf and soil sampling and irrigation scheduling also helps greening-affected trees,” he said.
Research conducted since greening was detected in 2005 has necessitated changes in many production practices, including nutrient application rates, irrigation scheduling, soil pH management and the use of citrus under protective screens (CUPS), Kadyampakeni said.
He cited the following as key updates:
- Chapter 2 highlights the importance of soil pH and soil organic matter management to improve tree performance in the era of HLB. Soil pH measures acids or bases in the soil that can affect the presence and availability of nutrients.
- Chapter 6 describes the importance of what Kadyampakeni calls “spoon-feeding” HLB-affected trees. Growers can do this by using controlled-release or liquid fertilizers, so nutrients go move easily from the soil into the tree. Greening-affected trees have limited capacity — a compromised root structure — to take up nutrients.
- Chapter 8 describes new findings drawn from several years of experiments on improving tree performance through balanced soil nutrition. In the same chapter, the authors describe improved soil pH moderation practices and root-health management for increasing productivity of HLB-affected trees.
- Chapter 9 shows the importance of managing water differently for HLB-affected trees. Such trees have limited capacity to absorb water. Recommendations include frequent irrigation to increase water in the root zone in the soil beneath trees.
- Chapter 11 includes information on the CUPS strategy to grow trees in screen-enclosed structures. The screening system keeps the Asian citrus psyllid off citrus trees. The psyllid is the insect that transmits the pathogen that causes citrus greening.
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