Effects and Application of Nickel to Pecan

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Effects and Application of Nickel to Pecan

• Lenny Wells
• UGA Extension Horticulture Pecans

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Mouse-ear (since 1917)
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Mouse-ear

• Found in certain virgin sandy soils
• Increasingly common in second generation orchards
  

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History of Zinc Application to Orchards

• 3 to 5 foliar sprays of zinc
• each year for 30 70 years
• 4-16 lbs Zn per acre per year

100 to 500 lbs Zn per acre per lifetime of
orchard Zn concentrated in soil at base of
trees
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Typical Ni deficiency symptoms
Urea toxicity zone
--Autumn or spring foliar Ni sprays corrected
mouse-ear.
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Disrupted hormonal physiology and growth
processes
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Ni Deficiency Symptoms
-brittle wood -reduced vigor and
flowering -Failure to survive dormant season
(cold injury?) -dead or dark colored roots,
reduced number of feeder roots -death of shoots
and limbs -tree death
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Causes of Ni Deficiency

• Ni deficiency occurs when
• 1) Soil Ni is low
• 2) Low soil Ni, plus
• high soil Ca and Mg
• 3) High soil Zn, or Cu, or Fe
• 4) Rootknot or ring nematodes,
• plus any of the above
• 5) Dry soils at bud break
• 6) Anything that prevents feeder root
  development

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Ni Nutrition of Perennial Crops?
Sufficient
Critical range lt0.01 to 5 ppm
Excessive gt50 ppm
3-5 -15 ppm
Plant Yield
Deficient
Injury
Nutrient Concentration in Tissue
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Nickel PlusLiquid spray formulation 6 Nickel
as Ni lignosulfonate10 Nitrogen as Urea3.2
Sulfur

Can be tank-mixed with other nutrients and
pesticides
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Nickel Plus
Application To ensure adequate Ni levels in
leaf Apply 1 pt/A in spring (April) while
canopy is developing (parachute stage) 2nd
application 1 pt/A 30-60 days after 1st
appl. When mouse ear present or newly
transplanted trees Additional application of
1.5-2 pts/A in late Sept.-early October
before leaf fall to prevent mouse ear in the
spring flush. Leaves will not absorb Ni until
after parachute stage in spring. By then Ni
deficiency may have already damaged tissue.
Closely monitor Ni concentrations in tissue
by leaf sampling (15 ppm)

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Zinc Management

• Do not use Zinc application as a general practice
• Do not apply Zn unless leaf samples indicate less
  than 50 ppm or visual symptoms present
• 2 lbs Zn sulfate/100 gal
• 3 lbs Potass. Nitrate

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Boron

• May help improve shell elasticity
• Role of B will be more important on sandy soils
  (esp. during drought stress)
• Current leaf recommendations 15-50ppm
• Evidence that physiological processes disrupted
  at less than 50 ppm-(50-100ppm)
• Keep pH below 7.5

• Usually will not show visual symptoms of
  deficiency
• High K in soil may suppress B uptake
• Involved in productions and movement of sugars
• Affects trees ability to remove N from the soil
• Longer leaf retention in fall (Blackmon 1941)
• May help improve return bloom nut quality