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Banding Fertilizers in Pecan Orchards

Michael SmithDepartment of Horticulture &

L.A.Oklahoma State University

Okla

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yNecrotic leaves near shuck split

on Pawnee

July leaf P 0.114% and leaf K 0.62%

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Nut count, kernel %, kernel grade and return bloom improved with

higher leaf P and K concentrations.

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yCultivar: Pawnee Age: 9 years Soil: Dennis silty clay loam Irrigation: subsurface dripTreatments:

Control – N only; P – N + P; K – N + K; PK – N + P + K

2009All trees: March 52 lb/acre N

May 88 lb/acre NP: March 131 lb/acre P2O5

K: March 69 lb/acre K2OPK: March P rate + K rate2010All trees: March 104 lb/acre NP: March 262 lb/acre P2O5

K: March 138 lb/acre K2OPK: March P rate + K rate

2011All trees: March 104 lb/acre NP: March 262 lb/a P2O5

K: March 138 lb/acre K2OPK: March P rate + K rate

2012All trees: March 52 lb/acre N

May 75 lb/acre NP: March 131 lb/acre P2O5

K: March 69 lb/acre K2OPK: March P rate + K rate

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July leaf P

None P K P + K0.000.020.040.060.080.100.120.14

Leaf

P (%

DW

) 2009

None P K P + K0.000.020.040.060.080.100.120.14

Lea

f P (%

DW

) 2010

None P K P + K0

0.020.040.060.08

0.10.120.14

Leaf

P (%

DW

)

2011

None P K P + K0.000.020.040.060.080.100.120.14

Leaf

P (%

DW

)

2012

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yDrought started in 2010 and has continued to intensify.

Non-irrigated 2 miles south

Surface water irrigation source

Trees on survival irrigation ration

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July leaf K

None P K P + K0.00.20.40.60.81.01.2

Lea

f K (%

DW

)

2009

None P K P + K0.00.20.40.60.81.01.2

Leaf

K (%

DW

) 2010

None P K P + K0.0

0.2

0.4

0.6

0.8

1.0

1.2

Leaf

K (%

DW

)

2011

None P K P + K0.0

0.2

0.4

0.6

0.8

1.0

1.2

Leaf

K (%

DW

)

2012

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Leaf symptoms

Element applied

Trees with any necrotic leaf symptoms

29 Aug. 2009(%)

Tree necrosis rating4 Oct. 2010

Tree necrosis rating

31 Aug. 2012

None 66 3.7a 4.0aP 33 1.5b 1.7bK 100 3.3a 4.3aP + K 17 1.3b 1.5b

Rating1

Rating3

Rating 5

Symptoms appear closely linked to P shortage, even in July.

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y2011 1-year-old branches with fruit

0

10

20

30

40

50

60

Control K P K + P

1-ye

ar-o

ld b

ranc

hes

with

frui

t (%

)

Fruiting Vegetative2010 branch type

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y2012 1-yr-old branches with fruit

Control K P K + P0

102030405060708090

100

2011 vegetative shoots only

1-ye

ar-o

ld b

ranc

hes w

ith fr

uit

(%)

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yN & P on ‘Chickasaw’ near

Baconton, GATreatments: March 0 or 50 lb/a N Late July 0 or 100 lb/a N Late July 0 or 150 lb/a P2O5

N source: (NH4)2SO4

P source: Triple super phosphateReps: 6 single trees

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yLate July N & P application on next year current season shoots fruiting

None P N N + P0

102030405060708090

Terminal shoots All shoots

P2O5 @ 150 lb/acre and N @ 100 lb/acre

Cur

rent

seas

on sh

oots

frui

ting

(%)

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yP & K in the rest of the field

Applied with spinner off

Note K band

18-46-0 banded in March

18-46-0 (DAP), 0-46-0 (TSP), or 0-0-60 banded increases availability of those nutrients. Broadcast applications are generally ineffective.

Healthy trees without deficiency symptoms as a result of banding

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yTommy Bryant applying 18-46-0 in an orchard near Albany, GA

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yPotassium banding on ‘Desirable’

in GeorgiaWood, Wells & Funderburke, 2010

• ≈25 years-old on Elliott rootstock• Faceville sandy loam soil• 30’ x 60’ spacing• Drip irrigated from 1 line on each side• 0-0-62 applied March in ≈ 6” wide band spanning several

emitters. Applied on each side of the tree within the herbicide treated area.

• Rates from 0 to 53 lb/tree K2O (0 to 1282 lb/acre K2O; 0 to 2068 lb/acre 0-0-62)

• Measurements were at the end of stage 2 fruit drop, i.e. June drop.

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yPotassium concentration in leaves, retain fruit and aborted

fruit of ‘Desirable’ the 1st year following application

0 5 10 15 20 25 30 35 40 501.0

1.1

1.2

1.3

1.4

1.5

1.6

Potassium applied as soil band (lb/tree K2O)

Pota

ssiu

m c

onc.

(% D

W)

Leaves

206 1000 2000

Retained fruit

Aborted fruit

0-0-62 applied in band (lb/acre)

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yFruit retention following K

banding in March 2006

0 5 10 15 20 25 30 35 40 5040

45

50

55

60

65

70

Potassium applied as a band (lbs/tree K2O)

Frui

t ret

aine

d (%

of t

otal

) 2006

2008

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yYield following March

2006 K banding

0 5 10 15 20 25 30 35 40 5050

60

70

80

90

100

Potassium applied as soil band (lb/tree K2O)

Yie

ld (l

b/tr

ee) 2006

2008

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yZinc banding of ‘Desirable’ in Georgia

Wood, 2007• 15’ x 30’ (97 trees/acre)• 4-years-old at beginning of study• Faceville fine sandy loam• Drip irrigated

– Buried line 4’ from trunk on each side of tree– Water delivery on surface 3’ apart– 1 gph operated 8 to 12 hours/day– Irrigation lines within herbicide strip

• ZnSO4 or ZnO banded 4” x 13’ over drip line• 0 to 9.3 lb Zn/tree (0 to 25 lb ZnSO4; 0 to 12 lb ZnO)

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yLeaf Zn following a single application

Wood considered 50 ppm as threshold

0102030405060708090

100110

Banded Zn (lb/tree)

Lea

f Zn

(ppm

DW

)

0

0.0727

5132

2751

3228

0.1455

0264

5502

646

0.2910

0529

1005

291

0.5820

1058

2010

582

1.164

0211

64021

16

2.3280

4232

8042

33

4.6560

84656

08466

9.3121

6931

2169

320

20

40

60

80

100

Banded Zn (lb/tree)

Lea

f Zn

(ppm

DW

)

0

0.0727

5132

2751322

8

0.1455

0264

5502

646

0.2910

0529

1005

291

0.5820

1058

2010582

1.1640

21164

02116

2.3280

4232

8042

33

4.6560

8465

6084

66

9.3121

6931

2169

320

20

40

60

80

100

Banded Zn (lb/tree)

Lea

f Zn

(ppm

DW

)

0

0.0727

5132

2751322

8

0.1455

0264

5502

646

0.2910

0529

1005

291

0.5820

1058

2010582

1.1640

21164

02116

2.3280

4232

8042

33

4.6560

8465

6084

66

9.3121

6931

2169

320

20

40

60

80

100

Banded Zn (lb/tree)

Lea

f Zn

(ppm

DW

)

1st year 2nd year

3rd year 4th year

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ySummary

• Applying phosphorous, potassium and zinc in bands within the wetted area of drip irrigated trees is effective.

• Phosphorus and potassium can be applied as a bulk blend.• DO NOT APPLY ZINC IN THE SAME AREA WHERE

PHOSPHORUS WAS APPLIED.• Similar results will probably be obtained when applied within

the wetted area of micro-sprinkler or sprinkler irrigated orchards.

• Banding about mid-way between the trunk and dripline should be beneficial on non-irrigated orchards, but the effectiveness will probably be reduced.