Root-Shoot Nutrient Dynamics of Huanglongbing-Affected Grapefruit Trees

Area of Science:

• Horticultural science
• Plant nutrition
• Agricultural science

Background:

• Huanglongbing (HLB) significantly reduces fine root mass, impairing nutrient uptake in citrus trees.
• Understanding nutrient translocation is crucial for optimizing fertilizer strategies in HLB-affected orchards.

Purpose of the Study:

• To investigate the impact of different fertilizer application methods on nutrient translocation in HLB-affected grapefruit trees.
• To identify specific tree components where nutrients accumulate under varying fertilization regimes.

Main Methods:

• Field study involving HLB-affected grapefruit trees grafted on 'sour orange' rootstock.
• Application of three fertilizer types: soluble granular, controlled release fertilizer (CRF), and liquid.
• Destructive analysis of tree components (roots, trunk, branches, leaves) for nutrient and biomass content after three years.

Main Results:

• Fertilizer application methods influenced nutrient allocation in leaves, twigs, and feeder roots, though no consistent pattern emerged.
• Leaves, twigs, and feeder roots exhibited higher nutrient concentrations compared to other tree parts.
• Significant differences in nutrient content were observed across tree components based on fertilization strategy.

Conclusions:

• Fertilization methods demonstrably affect nutrient distribution within HLB-affected citrus trees.
• Further research is warranted to explore optimal fertilizer application methods and rates for managing HLB.
• Targeting nutrient application to specific tree components may enhance nutrient use efficiency in diseased citrus.