Wild Blueberry Best Management Practices for Fertilizers

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1

John M. Smagula

Professor of HorticultureProfessor of HorticultureDept. Plant, Soil, and Environmental

Sciences

Best Management Practices for Fertility Management

1. Basics of wild blueberry plant nutrition

2. Evaluating wild blueberry health

3 Nutrient management strategies

4. Fertilizer choices

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Basics of wild blueberry nutrition

Where are the nutrients in a–Where are the nutrients in a blueberry soil?

Lowbush Blueberry Soil ProfileLowbush Blueberry Soil Profile

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1 51.5 inches

Where are the nutrients?

Organic pad

Sandy Soil

N, P, K, Mg, BCa,

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Basics of wild blueberry nutrition

How does the plant get the–How does the plant get the nutrients?

RhizomeRoot

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RhizomeNN

N

NN

N

Roots

Best Management Practices for Fertility Management

1. Basics of wild blueberry plant nutrition

Evaluating wild blueberry health

3 Nutrient management strategies

4. Fertilizer choices

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Evaluating wild blueberry health

–How can we assess nutrient status?

Assessing Plant Health

S t• Symptoms:–Abnormal leaf color

–Poor stem growth

Poor fruit set low yield–Poor fruit set, low yield

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Plant Yield and Nutrient Content

Transition

Zone

Adequate ZoneY

ield

ZoneCritical

concentration

Deficient Zone

Concentration in tissue

Assessing Plant Health

• Symptoms:y p– Abnormal leaf color

– Poor stem growth

– Poor fruit set, low yield

il d• Test Soil and Leaves

Correct pH Low N and P

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What is soil pH?• Measure of acidity

H OH

7140

Neutral pH

HOH

HOH

7140

Low pH

7140

High pH

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What is soil pH?

• Measure of acidity• Measure of acidity

• Sample soil – determine soil pH

– Depth – 3 inches3 in.

How to sample blueberry soil?

• Soil sampling methods• Soil sampling methods– Random sample to represent entire field

– Send to the Maine Soil Testing Service for analysis

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What is soil pH?

• Measure of acidity• Measure of acidity

• Sample soil to determine soil pH

• How to lower soil pH?

Lowering Soil pH to 4.0using Sulfur

• Original pH Pounds Sulfur/acre• Original pH Pounds Sulfur/acre

5.00 1,000

5.10 1,100

5.20 1,200

5 30 1 3005.30 1,300

Cultural Management fact sheet - 254-Cultural Management pH

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Lowering Soil pH to 4.0using Sulfur

• Precautions to avoid injury to blueberries• Precautions to avoid injury to blueberries– Apply before blueberry shoots emerge

– Do not apply more than 1000 lbs/a of sulfur in any given year

– Do not apply when ground is saturated

Leaf Samples better than Soil Samples

• Some nutrients are “tied up” on soil• Some nutrients are tied up on soil particles and not available to plant

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N - 1.6%

P - 0.125%B - 24 ppm

Assessing Plant Health

• Proper leaf sampling methods• Proper leaf sampling methods– Sample all leaves on a stem

– Random sampling across the field

– Taking leaf samples at the correct stage of development.

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N - 1.6%P - 0.125%B - 24 ppm

Plant health reflected in leaf nutrient concentrations

Nutrients

Major - needed in large quantities1.N - nitrogen Ca -calcium Fe - ironP - phosphorus Mg -magnesiumK - potassium S - sulphur

Minor - important, but needed in small quantitiesB - boron

2.B boronCu - copperMn - manganese

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Nutrient Movement in the Plant

Some nutrients move more easily 1. ythroughout the plant.

Mobile vs Immobile Nutrients2.

youngest leaf

Old t l fOldest leaf

RhizomeNN

N

NN

N

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Mobile ElementNPKMg

Deficiency appears in lower leaves

Immobile Element

BCa

Deficiency appears in upper leaves

*movement affected by moisture availability

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N P

2 00 % 143 %

Mobile

1 94 %

2.03 %

2.00 % .143 %

.117 %

112 %

AVERAGE OF 7 CLONES

1.94 % .112 %

Boron

16 ppm

Immobile

26 ppm

20 ppm

pp

pp

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Sample all leaves on stem

Trevett's Standard =

Sample many clones in a fieldPhosphorus

.136 %

.135 %

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Sample many clones in a field

.136 %

.135 %.118 %

.119 %

.127 %.119 %

.120 %

.119 %

.119 %

AVE = .124 % P

Correct Leaf Sampling Time

• Take leaf tissue samples at the “tip dieback”• Take leaf tissue samples at the tip-dieback stage– What is the tip dieback stage and why is this

important?

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Seasonal Trend of Nutrients in LeavesNitrogen

3 5

1

1.5

2

2.5

3

3.5

Tip dieback

Maine Agricultural Experiment Station Bulletin 665. Trevett

16 23 6 14 27 4 11 24 31 7 15 .0

0.5

1

June July August September

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Accurate Leaf SamplingAccurate Leaf Sampling•• Sample only sweet low not sourtopSample only sweet low not sourtop

•• Samples at 90% tip diebackSamples at 90% tip diebackp pp p

•• Sample 30 or more clonesSample 30 or more clones

Wild Blueberry Plant Ti ssue Bag

INSTRU CTIONS

See Wild Blueberry Fact Sheet #222 for complete instructions

One Sample Per BagCut 3 stems from 30 clones throughout the field

* Do not include any soil particle on p lants

* Do not-mix in other vegetation

*

See Wild Blueberry Fact Sheet #222 for complete instructions

If samples have pesticide, dust res idue or soil on them, they must be rinsed

*Hold samples in dry, clean area free from con tamination

SEN D sample to : Analytical Lab Room 407Univers ity of M aine5722 Deering HallOrono, M E 0446905722

COST per sample: $18.00 w/leaves stripped from stems$21.00 w/leaves on stems(make check payable to Analytical(make check payable to AnalyticalLab)

Name:______________________________________

Farm Name:_________________________________

Address:_____________________________________

Town:_______________State:_____________Zip:____

Phone:__________

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Best Management Practices for Fertility Management

1. Basics of wild blueberry plant nutrition

2. Evaluating wild blueberry health

Nutrient management strategies

4. Fertilizer choices

Current Fertility Management Practices

Take leaf tissue samples at tip-dieback stage.Cut stems at ground level (sample all leaves)Follow recommendations for Urea (N), MAP ( ),(N + P), or DAP (2 x N + P)

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Effect of Fertilizer Timing on Yield

2000 Study

10

12 5

a

2

4

6

8

10

1

2

3

4

c

aba

bc

cc

400lbs DAP/acre applied on indicated dates. , Significance level = 0.01%.

ControlMay 17

May 31June 14

June 28July 12

.0 0

Does fertilizing based on leaf Does fertilizing based on leaf tissue analysis work?tissue analysis work?

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Leaf Nitrogen

2

2.4

ba

0.4

0.8

1.2

1.6

bstd

Mean separation by Duncan's Multiple range test, 1% level, DAP at 80 lbP/acre.

CONTROL DAP0

Leaf Phosphorus

0 15

0.175

a

0.025

0.05

0.075

0.1

0.125

0.15b

std

Mean separation by Duncan's Multiple range test, 1% level. DAP at 80 lbP/acre.

CONTROL DAP0

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Stem Characteristics

1.4

1.6a

0 2

0.4

0.6

0.8

1

1.2

b

Mean separation by Duncan's Multiple range test, .01% level. DAP at 80 lbP/acre.

CONTROL DAP0

0.2

Figure

Control ap +

DAP

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Stem Characteristics

200

250 a

50

100

150

200

b

Mean separation by Duncan's Multiple range test, 0.1% level. DAP at 80 lbP/acre.

CONTROL DAP0

Yield

10

12a

2

4

6

8

10

b

Mean separation by Duncan's Multiple range test, 0.03% level. DAP at 80 lbP/acre.

CONTROL DAP0

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Potential ProfitabilityFertilizer cost* Blueberry Yield

(lbs/acre)

Crop Value**

($)

Profit due to 

fertilization(lbs/acre) ($) fertilization

($)

0 1000 540

158 1,500 652 112

158 2,000 922 382

158 3,000 1462 922

158 4,000 2002 1,462

*Application of 400 lbs of DAP per acre, assuming $33.25/100 lbs DAP and $25/acre application cost.**Crop value based on the ten year average price of $0.54/lb minus the fertilizer and application costs.

Best Management Practices for Fertility Management

1. Basics of wild blueberry plant nutrition

2. Evaluating wild blueberry health

3. Nutrient management strategies

Fertilizer choices

3/21/2011

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DAPDAP

•• 100 lb bag of DAP (18100 lb bag of DAP (18 –– 4646-- 0)0)•• 100 lb bag of DAP (18 100 lb bag of DAP (18 4646-- 0)0)

–– 18 % N or 18 lb actual N18 % N or 18 lb actual N

–– 46 % P46 % P22OO55 (which is only 44% P) (which is only 44% P) S 46 lb f PS 46 lb f P OO 44 20 2 lb f t l P44 20 2 lb f t l P•• So 46 lbs of PSo 46 lbs of P22OO55 x .44 = 20.2 lbs of actual P x .44 = 20.2 lbs of actual P

•• For each 100 lbs of DAP you apply almost equal For each 100 lbs of DAP you apply almost equal amounts of N and P, about 20.amounts of N and P, about 20.

University of Maine 09/14/95Analytical Lab

LOWBUSH BLUEBERRY FOLIAR ANALYSIS REPORT

COASTAL BLUEBERRY SERVICES, INC Job #: 1703

PO BOX 522 Lab no.: 232

UNION ME 04862

FIELD NAME fi ldFIELD NAME: growers field

NUTRIENT LEVEL FOUND

Nitrogen % 1.55Calcium % 0.496Potassium % 0.475Magnesium % 0.251Phosphorus % 0.118Aluminum (ppm) 81.9Boron (ppm) 22.7Copper (ppm) 5.20Iron (ppm) 45.0ppManganese (ppm) 756Zinc (ppm) 10.6

RECOMMENDED NUTRIENT AMENDMENTS

Apply 70 lb/A nitrogen and 180 lb/A phosphate.

Suggested source: 400 lb diammonium phosphate (18-46-0) per acre.

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Fertilizer Choices

– How can we best supplement nutrients?

How many prune-year applications are needed?

Phosphorus Study

0.11

0.125

0.14

0.1551989 1989+1991

P standard

1991 data

0 20 40 60 800.08

0.095

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How many prune-year applications are needed?

Phosphorus Study

0.095

0.11

0.125

0.14

0.155 1989 1989+91 1989+91+93

P standard

1993

0 20 40 60 800.08

Thank You

• Jack Smagula• Jack Smagula

• Professor of Horticulture

• University of Maine in Orono

• (207) 581-2925

l @ i d• smagula@maine.edu