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Grow Better Blueberries with Haifa products

Nutrition of bluerries: general rules

When setting the application rates, consider expected yield and required balance of nutrients
♦ Provide complete fertilization, with macro- and micro-nutrients
♦ Consider cation ratios Ca/K, Ca/Mg, Ca/(K+Mg)
♦ Consider NH4/NO3 ratio. The majority of nitrogen should be supplied as nitrate
♦ Use soluble and chloride-free potassium
♦ Use diagnostic tools such as soil analysis, foliar, suction probes, chlorophyll meters, etc.
♦ Split applications according to the plant’s uptake dynamics

 

Berries hate salinity:

Berry type

EC (dS / m) at which the yield decreased by:

 

10%

25%

50%

Blackberry

1.5

2.0

2.5

Blueberry

1.0

1.5

2.0

Raspberry

1.5

2.0

2.5

Considerable yield reduction occurs at relatively low EC levels.

 

Nitrogen Deficiency:

  • Nitrogen leaching, resulting from intensive rains or excessive irrigation, is a common cause of deficiencies
  • Typical symptoms: small pale leaves, sometimes with tiny red spots
  • Blueberries are salt-sensitive, so excessive N fertilization may cause mortality of young plants
  • Ammonium is the preferred form of nitrogen for blueberries
  • Ammonium nitrate can be used in fertilizer mixes: 

       ​- Where the nitrate portion of the mix constitutes a minor part of the total nitrogen in the mix and the soil pH is below 5.3.
       - For very light (20 pounds per acre or less) applications of nitrogen where a small amount of nitrogen is needed.

  • Urea and controlled release fertilizers are also suitable sources of nitrogen for blueberries
  • In the soil, urea is a rapidly converted to ammonium, which is readily absorbed by the plant
  • In soils where the pH is on the high end of the range for blueberries (above 5.0), use a more acid-forming fertilizer such as ammonium sulfate

 

Timing of nitrogen applications for blueberries in Alabama

Phosphorus in Blueberries:

 

  • Phosphorus is very important for the root establishment and for energy transfer in the plant
  • Many blueberry fields are low in P:

         ​ - In acidic soils P availability is low

          - In sandy soils P is prone to leaching
 

  • Pre-plant application of P is advisable
  • High levels of phosphorus in the soil can tie up iron, making it unavailable to the blueberry plant
     

Recommended application rates

Application rate

Soil test P (0-45 cm / 0-12”)

Lb/acre

Kg/ha

NaHCO3

Bray I

NaOAc

100

112

0-4

0-10

0-1

80

90

4-8

10-20

1-2

60

67

9-11

20-30

2-3

30

34

12-14

30-40

3-4

10

11

15-17

40-50

4-5

0

 

18-25

50-100

5-10

0

 

Over 25

Over 100

Over 10

 

Potassium in blueberry:

  • Potassium is essential for photosynthesis and water regulation. 
  • On bearing plants, the annual potassium requirements can be supplied by 1-2 applications

 

Potassium recommended rates:

Application rate

Soil test K
(0-45 cm / 0-12”)*

* Soil extract
in sodium acetate

Lb/acre

Kg/ha

80

90

0-50 ppm

50

56

50-75 ppm

30

34

75-100 ppm

0

0

Over 100

  • For established plants, determine K application rates according to soil analysis
  • In general:

           - To correct shortage apply 113-224 kg/ha (100-200 lbs/acre) K2O

           - To maintain adequate level apply 56-113 kg/ha (50-100 lbs/acre) K2O

 

 

Secondary elements:

  • Blueberries have low calcium requirement
  • Excessive calcium may cause iron deficiency
  • Liming

           - Only when soil pH is below 3.6

           - Lime application rate: 560 kg/ha (500 lbs/acre)

           - Do not exceed this rate 

 

 

On highbush blueberries, classic magnesium deficiency is a green "Christmas Tree"
in the center of a chlorotic leaf. 

It usually occurs on the older leaves

 

 

 

On young rabbit-eye plants

magnesium deficiency is commonly shown as

pink edges and interveinal yellowing of leaves
 

 

 

Ca-Mg balance:

  • Calcium - magnesium levels should be kept in balance
  • The normal range is 1:8 to 1:10 (Mg:Ca)
  • High calcium levels can induce magnesium deficiency
  • To correct magnesium deficiency, apply 16.8 kg/ha (15 Lbs/acre) magnesium

 

Calcium and fruit quality

  • Pre-harvest calcium sprays. 

           - Increase firmness of the berries

           - Extend shelf-life

           - Reduce Botrytis rot

Blueberry showing Ca deficiency (left); inside view, note corky area (right).

 

Iron in blueberry:

 Iron deficiencies is likely to occur when soil pH is too high

♦ The best treatment is lowering soil pH

♦ Foliar sprays of Iron chelate may alleviate some leaf symptoms but usually do not improve overall plant vigor 
 

 

 

 

Nutrigation™  program for blueberries:

Recommended fertilizers (kg/ha)

Nutrients required (kg/ha)

Timing

Multi-K

MAP

A-S

K2O

P2O5

N

60

12

32

30

7

15

Leaf emergence

90

16

42

40

10

20

Flowering

110

21

53

50

13

25

Fruit set

110

20

53

50

12

25

Fruit growth

60

13

30

30

8

15

Fruit maturation

430

82

210

200

50

100

Total

 

Texas fertigation schedule for blueberries:

Grams/plant/week

Plant diameter
(feet)

K

P

N

0.5

0.5

1

1

0.75

0.75

1.5

2

1

1

2

3

1.2

1.2

2.5

4 and up

 

 

Nitrogen fertigation for blueberries:

1.Reduce annual N rate by 1/3, compared to soil application

2.Start application 2-3 weeks after bud break, continue into July

 

 

Leaf analysis

Suggested critical levels of nutrients in highbush and rabbiteye blueberry leaves

Excess

Normal:

rabbiteye

Normal:

highbush

Deficiency

Nutrient

2.5%<

1.2-1.7%

1.8-2.1%

< 1.7%

N

0.8%<

0.08-0.17%

0.12-0.4%

< 0.1%

P

0.95%<

0.28-0.6%

0.35-0.65%

< 0.3%

K

1%<

0.24-0.7%

0.4-0.4%

< 0.13%

Ca

0.45%<

0.14-0.2%

0.12-0.25%

< 0.08%

Mg

NA

NA

0.12-0.2%

< 0.1%

S

 

Excess

Normal:

rabbiteye

Normal:

highbush

Deficiency

Nutrient

450 ppm<

25-100 ppm

50-350 ppm

< 23 ppm

Mn

400 ppm<

25-70 ppm

60-200 ppm

< 60 ppm

Fe

80 ppm<

10-25 ppm

8-30 ppm

< 8 ppm

Zn

100 ppm<

2-10 ppm

5-20 ppm

< 5 ppm

Cu

200 ppm<

12-35 ppm

30-70 ppm

< 20 ppm

B

 

Need more information about growing blueberries? You can always return to the blueberry fertilizer .