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Citrus Nutrition Management Practices

Jamie D. Burrow, Tripti Vashisth, Mongi Zekri, Stephen H. Futch, and Arnold Schumann

Mineral Nutrients

  • Plant mineral nutrients play an essential role in the plant's life cycle; there are 14 mineral nutrients that are recognized as essential for normal plant growth and development.

  • Essential nutrients are not simply plant food necessary for optimum plant growth and yield, they also influence plant resistance or susceptibility to pathogens and pests.

  • Nutrients aid in the formation of mechanical barriers, primarily through the development of thicker cell walls and the synthesis of natural defense compounds (phytoalexins, antioxidants, and flavonoids) to provide protection against pathogens.

Benefits of Plant Nutrition Management

  • Balanced and complete nutrition can help trees in performing proper functions.

  • Mineral nutrition is an environmental factor that can be controlled in agricultural systems.

  • Proactive and timely nutrition management can enhance a plant's efficiency to absorb nutrients. Consistently available macro and micro nutrients improve metabolism and other processes in the plant.

Nutrition Balance and Disease Resistance

  • Plants with an optimal nutritional status have the highest tolerance to pests and diseases. Any nutritional deficiency hinders plant metabolism and results in a weakened plant, which may lowers disease resistance. Disease susceptibility increases as nutrient concentrations deviate from the optimum.

  • The goal is to maximize yield and the potential for disease and pest control through mineral nutrition and fertilizer applications.

Nitrogen (N)

Deficiency Symptom: entire leaf yellowing of old leaves

Function: vegetative growth, flowering, fruit yield

Application Method: foliar and soil

 

Figure 1. Nitrogen (N)
Figure 1.  Nitrogen (N)

 

Phosphorus (P)

Deficiency Symptom: fruit has thick rind and hollow core; leaf symptoms are rare in Florida

Function: photosynthesis and plant energy

Application Method: foliar and soil

 

Figure 2. Phosphorus (P)
Figure 2.  Phosphorus (P)

 

Potassium (K)

Deficiency Symptom: yellowing of the tips and margins which becomes broader

Function: yield, fruit size, juice quality

Application Method: foliar and soil

 

Figure 3. Potassium (K)
Figure 3.  Potassium (K)

 

Calcium (Ca)

Deficiency Symptom: yellowing of leaf margins; small, thickened leaves

Function: important component of cell wall (overall tree growth)

Application Method: foliar and soil

 

Figure 5. Calcium (Ca)
Figure 5.  Calcium (Ca)

 

Magnesium (Mg)

Deficiency Symptom: inverted 'V' pattern at base of leaf

Function: main element in chlorophyll; aids in photosynthesis

Application Method: foliar and soil

 

Figure 6. Magnesium (Mg)
Figure 6.  Magnesium (Mg)

 

Sulfur (S)

Deficiency Symptom: pale green to yellow in color on new growth

Function: protein synthesis, amino acid, chlorophyll production

Application Method: foliar and soil

 

Figure 7. Sulfur (S)
Figure 7.  Sulfur (S)

 

Iron (Fe)

Deficiency Symptom: green veins on a light green leaf; symptoms appear first on new foliage

Function: essential for synthesis of chlorophyll and energy production

Application Method: soil

 

Figure 8. Iron (Fe)
Figure 8.  Iron (Fe)

 

Copper (Cu)

Deficiency Symptom: 'S' curved branching, inter-nodal stem gumming, twig dieback

Function: proper enzyme activity and metabolism; plays essential role in chlorophyll formation

Application Method: foliar and soil

 

Figure 9. Copper (Cu)
Figure 9.  Copper (Cu)

 

Zinc (Zn)

Deficiency Symptom: leaf is yellow with green veins

Function: plant metabolism, growth-promoting substances in plants (auxins)

Application Method: foliar and soil (soil applications are not recommended on calcareous soils)

 

Figure 10. Zinc (Zn)
Figure 10.  Zinc (Zn)

 

Manganese (Mn)

Deficiency Symptom: dark green bands along midrib and main veins surrounded by light green interveinal areas

Function: energy metabolism

Application Method: foliar and soil (soil applications are not recommended on calcareous soils)

 

Figure 11. Manganese (Mn)
Figure 11.  Manganese (Mn)

 

Boron (B)

Deficiency Symptom: corky veins

Function: movement of sugar in phloem; translocation of sugar

Application Method: foliar and soil

 

Figure 12. Boron (B)
Figure 12.  Boron (B)

 

Molybdenum (Mo)

Deficiency Symptom: large interveinal yellow spots

Function: plant protein formation

Application Method: soil or foliar

 

Figure 13. Molybdenum (Mo)
Figure 13.  Molybdenum (Mo)

 

 

The role of Chlorine (Cl) and nickel (Ni) in citrus trees is not well defined.

Liebig's Law of the Minimum

  • The leaky barrel illustrates Liebig's law of the minimum.

  • Just as the capacity of a barrel with unequal length staves is limited by the shortest stave, so too is a plant's health, growth, and yield limited by the nutrient in shortest supply.

 

Figure 4. 
Figure 4. 
Credit: UF/IFAS Communications

 

The Right Nutrient Program Stewardship for Best Management Practices (BMP)

 

Figure 14. The RIGHT Nutrient Program Stewardship for Best Management Practices (BMP)
Figure 14.  The RIGHT Nutrient Program Stewardship for Best Management Practices (BMP)

 

Resources

Nutrition of Florida Citrus Tree, Second Edition. Edited by Thomas A. Obreza and Kelly T. Morgan

A Guide to Citrus Nutritional Deficiencies and Toxicities. Steve Futch and D.P.H. Tucker

The Critical Importance of Citrus Tree Nutrition. Mongi Zekri

Photo Credits: Mongi Zekri, Tripti Vashisth, UF/IFAS Communications, and R.C.J. Koo

Tables

Table 1. 

Relative essential mineral element composition of a 6-year-old 'Hamlin' orange tree (excluding Cl and Ni). (Derived from Mattos et al. 2003).

Element

No. of Atoms Relative to Mo

% of Total Tree Dry Weight

Mo

1

0.00003

Cu

100

0.002

Mn

200

0.003

Zn

300

0.006

Fe

600

0.010

B

800

0.002

S

11,111

0.096

P

13,000

0.116

Mg

18,000

0.120

K

66,000

0.728

Ca

98,000

1.096

N

237,000

0.932

Source: Nutrition of Florida Citrus Trees, Second Edition. Edited by Thomas A. Obreza and Kelly T. Morgan

Footnotes

1. This document is HS1292, one of a series of the Horticultural Sciences Department, UF/IFAS Extension. Original publication date May 2017. Visit the EDIS website at https://edis.ifas.ufl.edu.
2. Jamie D. Burrow, Extension program manager, UF/IFAS Citrus Research and Education Center; Tripti Vashisth, assistant professor, Horticultural Sciences Department, UF/IFAS CREC; Mongi Zekri, Extension agent, UF/IFAS Extension Hendry County; Stephen H. Futch, Extension agent emeritus, UF/IFAS CREC; Arnold Schumann, professor, Department of Soil and Water Sciences, UF/IFAS CREC; UF/IFAS Extension, Gainesville, FL 32611.