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Wild Blueberry Best Management Practices for Fertilizers
3/21/2011
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
3/21/2011
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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
3/21/2011
3
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
3/21/2011
6
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:__________
3/21/2011
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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
27
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
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