1. Rebecca L. Darnell, University of Florida
Nitrogen in blueberry: A review
Rebecca L. Darnell, University of Florida

2. Blueberry industry in FL
Southern highbush blueberry
Based on V. corymbosum
Hybrids with wild species native to the southeastern U.S.
V. elliottii / V. darrowii / V. virgatum

3. Nitrogen and Iron are two important nutrients in blueberry production
Allocation of N - Storage vs current
N uptake and assimilation
Highbush vs sparkleberry

4. Seasonal N concentration in young blueberry canes and roots
Decrease in cane and root N
leading up to bloom in 2nd season
Roots
Continued decrease
in cane N through
harvest
Nitrogen (µg/mg DW)
1-May Jun Jul Oct Feb Apr May Jul Oct Jan
Leaf senescence
Budbreak
Harvest
Leaf senescence
Modified from Banados et al., 2012

5. Nitrogen content in blueberry during fruiting
Nitrogen (mg/plant part)
Dormancy Bloom Early Mid Fruit
devel devel harvest

6. Storage nitrogen content in blueberry during fruiting
Nitrogen (mg/plant part)
Dormancy Bloom Early Mid Fruit
devel devel harvest

7. Nitrogen content in blueberry during fruiting
Storage N
Nitrogen (mg/plant part)
Dormancy Bloom Early Mid Fruit
devel devel harvest

8. Soil adaptation Blueberry soils Mineral soils Acidic (pH 4.5-5.5)
High om - amended
NH4
pH>6.0
Low om
Accumulate NO3 over NH4

9. NH4
NO3

10. Dry weight (g)
New
Plant shoot Leaf Stem Root
NH * * * NO

11. NH4 vs NO3 uptake rates in blueberry
15N uptake (µg/g DW/h)
15NH4
15NO3
Time (h)

12. NH4 vs NO3 accumulation in blueberry
Nitrogen (mg/plant)
15NO3
Time (h)

13. NO3 assimilation limited in blueberry
15N content (mg/plant)
Total 15N
Assimilated 15N
Time (h)

14. N uptake and assimilation
Amino acids/proteins
NO2-
NH4+
*NR
NO3-
NO2-
2H+ NO3-
NH4+
*NR = nitrate reductase

15. NRA (nmol/g FW/h) Species Root Leaf HB blueberry 50-200 0
Strawberry
Apple
Peach
Calamondin

16. Are there Vaccinium species native to higher pH (nitrate predominant N form), low om soils?

17. arboreum “Sparkleberry” Native to the southeastern US
Vaccinium
arboreum
“Sparkleberry”
Native to the southeastern US
Tree-like growth habit
Deep root system – drought tolerant
Tolerates low organic matter soil, pH up to 6.7
N primarily in NO3 form

18. N uptake in sparkleberry vs blueberry
N uptake (mmol/plant/day)
sparkleberry
blueberry
NH NO3

19. Nitrate assimilation in sparkleberry vs blueberry
NR activity (nmol/g FW/h)
blueberry
NH NO3

20. NO3 uptake and assimilation in
sparkleberry is greater than in blueberry
Can we use sparkleberry to increase
adaptation of blueberry to more mineral
soils?

21. 1) Using sparkleberry in breeding 2) Using sparkleberry as a rootstock
Two approaches:
1) Using sparkleberry in breeding
2) Using sparkleberry as a rootstock
Other potential advantages:
Drought tolerance
Mechanical harvesting
Courtesy: J. Spiers

22. Blueberry Trees?

23. Don Merhaut Eric Ostmark Gerardo Nunez Carol Hamilton
Acknowledgements
Don Merhaut Eric Ostmark
Gerardo Nunez Carol Hamilton
Bruno Casamali David Norden
Robert Stacey
Valerie Jones
Paul Miller
Jeff Williamson
Jim Olmstead
Paul Lyrene
Steve Sargent
Funding: USDA SCRI Grant