Zinc Foliar Uptake EfficiencyZinc Foliar Uptake EfficiencyR. Scott Johnson

UC Extension Pomologistg

Reported Zn Uptake EfficienciesReported Zn Uptake Efficiencies

   6 %   Pi hi2.1 to 6.5%   Pistachios3.5%    Walnuts3 56.0%    Beans0 2%    Pecans0.2%    Pecans<1.0%  Citrus0.2 to 14.5%   Peaches

F t Aff ti Zi F li U t kFactors Affecting Zinc Foliar Uptake

Pl  S iPlant SpeciesZn FormulationZn Concentration in SolutionLength of Time for Uptakeg pZn Status of the PlantLeaf AgeLeaf AgeAdditives – Surfactants, Urea etc.

Zi M t i lZinc Materials

Basic Chemicals Zn sulfate

Chelates & Complexes EDTA

Zn oxide Zn carbonate

EDTA Lignosulfonate Amino acidZn carbonate

Zn chloride Zn oxysulfate

Amino acid Sugar Citric acid Zn oxysulfate

Zn nitrate Citric acid Fulvic acid, humic acid

Leaf Area of Individual Leaves

12.02) C t l

3.0

6.0

9.0

Leaf

Are

a (c

m ControlSulfateNitrateCarbohyOxide

0.0-10 0 10 20

Node from Time of Treatment

L

Comparing Zinc Formulations

Ranking Formulation Anion SizeSolubility(g/100 H2O) Phytotoxicity

Most Effective Zinc Chloride 35 432 High (58*)Most Effective Zinc Chloride 35 432 High (58*)

Almost As GoodZinc Nitrate 62 324 High (54)Zinc Nitrate Mix 62 & 96 324 High (59)

Next Best

Zinc Sulfate 96 50 Moderate (12)Zinc Carbohydrate 96 & ? High Moderate

&Zinc Polyamine 96 & 75-204 High ModerateZinc Glycine 96 & 75 Moderate (15)

Zinc EDTA 292 High LowLess Effective

Zinc EDTA 292 High LowZinc Leonardite 1000+ High LowZinc Oxysulfate 16 & 96 1.3 None

Least EffectiveZinc Phosphite 79 ? Low (17)Zinc Oxide

Suspension16 Insoluble None

F t Aff ti Zi F li U t kFactors Affecting Zinc Foliar Uptake

Pl  S iPlant SpeciesZn FormulationZn Concentration in SolutionLength of Time for Uptakeg pZn Status of the PlantLeaf AgeLeaf AgeAdditives – Surfactants, Urea etc.

Peach Seedlings - 68ZnSO4 Rate68Zn Taken Up by Plant as % of Applied

Peach Seedlings - 68ZnSO4 Rate68Zn Taken Up by Plant as % of Applieda e Up by a t as % o pp eda e Up by a t as % o pp ed

3

2

3

b b

a

%Uptake

%Uptake

1

2 b bb

0

1

d

c

UTC 100 200 400 1000 5000

Treatment - ppm ZincTreatment - ppm Zinc

Peach Seedlings - 68ZnSO4 Rate68Zn in Untreated Plant Organs

Peach Seedlings - 68ZnSO4 Rate68Zn in Untreated Plant OrgansU t eated a t O ga sU t eated a t O ga s

4 a

68Zn68Zn 3

4

b

From Fertilizer

(mg)

From Fertilizer

(mg)2 c

0

1e

ded

Treatment - ppm ZincTreatment - ppm Zinc

UTC 100 200 400 1000 5000

F t Aff ti Zi F li U t kFactors Affecting Zinc Foliar Uptake

Pl  S iPlant SpeciesZn FormulationZn Concentration in SolutionLength of Time for Uptakeg pZn Status of the PlantLeaf AgeLeaf AgeAdditives – Surfactants, Urea etc.

Recovery of Labelled 68Zn Sulfate Applied toRecovery of Labelled 68Zn Sulfate Applied toy ppLeaves of One-Year-Old Peach Trees in the Fall

y ppLeaves of One-Year-Old Peach Trees in the Fall

44

55DormantDormant One month after BloomOne month after Bloom

33

44% of

Label Z

% of

Label Z

11

22Zn

AppliedZn

Applied

00RootsRoots TrunkTrunk ShootsShoots NewNew

GrowthGrowthRootsRoots TrunkTrunk ShootsShoots

GrowthGrowth

F t Aff ti Zi F li U t kFactors Affecting Zinc Foliar Uptake

Pl  S iPlant SpeciesZn FormulationZn Concentration in SolutionLength of Time for Uptakeg pZn Status of the PlantLeaf AgeLeaf AgeAdditives – Surfactants, Urea etc.

18

Zinc Status Experiment

14

16

18HiControl

Hi+Sulfate

10

12

ea (c

m2)

LoControl

L +S lf t

4

6

8

Leaf

Are Lo+Sulfate

0

2

4

10 0 10 20 30-10 0 10 20 30Node From Time of Foliar Treatment

Zinc Status Experiment

High Zinc 6 0% Uptake of Foliar 68ZnHigh Zinc – 6.0% Uptake of Foliar 68Zn

Low Zinc – 7.2% Uptake of Foliar 68Zn

F t Aff ti Zi F li U t kFactors Affecting Zinc Foliar Uptake

Pl  S iPlant SpeciesZn FormulationZn Concentration in SolutionLength of Time for Uptakeg pZn Status of the PlantLeaf AgeLeaf AgeAdditives – Surfactants, Urea etc.

Zinc Uptake and Leaf Age(From work of Patrick Brown)(From work of Patrick Brown)

PistachioYoung Leaves – 6.5% Zn UptakeM t L 2 1% Z U t kMature Leaves – 2.1% Zn Uptake

WalnutNo Difference

F t Aff ti Zi F li U t kFactors Affecting Zinc Foliar Uptake

Pl  S iPlant SpeciesZn FormulationZn Concentration in SolutionLength of Time for Uptakeg pZn Status of the PlantLeaf AgeLeaf AgeAdditives – Surfactants, Urea etc.

Surfactants Added to 68Zn Sulfate

68Z

3

ab

aab

b bab

68Zn Uptake

(% of applied)2

b b

1

c

ControlNone

L77( 20)L77(.05)

SilSKinetic

Super 7

0c

Control L77(.20) SilSuper Super 7

F t Aff ti Zi F li U t kFactors Affecting Zinc Foliar Uptake

Pl  S iPlant SpeciesZn FormulationZn Concentration in SolutionLength of Time for Uptakeg pZn Status of the PlantLeaf AgeLeaf AgeAdditives – Surfactants, Urea etc.

Zinc FertilizationZinc Fertilization

A l  if  t       Apply if symptoms appear or leaf Zn < 10 to 12 ppm  or Sept shoot Zn < 20 ppmSept shoot Zn < 20 ppm

If needed in mature trees – If needed in mature trees –spray 4 to 8 lbs/acre of zinc sulfate (36% Zn) in early fall (3 ) y– can be applied with urea

http://ucanr.org/sites/fruitreport/p g p