1. Open Hydroponics – An Approach for Greening
Pete Spyke
Arapaho Citrus Management, Inc.

2. What is OHS? Elements: Drip irrigation Close spacing Fertigation
Canopy Mgmt
Intensive mgt.
High yields
Early $$

3. One approach to Greening
New grove goals:
Reach breakeven ASAP;
Improve overall income
Improve greening mgt.
Outrun tree losses!
Mature grove goals:
None – infection spreading too fast

4. WATER
Calculated for daily applications based on root growth, ET, and canopy development.
Apply in pulses.
Minimize effort for uptake.
Good root aeration.
Salinity Management.

5. CROPPING Occurs naturally in 2 years, or Enhanced with girdling.
Heavy Cropping aids in Tree Vigor Control

6. NUTRIENT MANAGEMENT Fertigate to provide non-limiting conditions
Amount of nutrients directly related to tree growth.
Proportions according to annual growth cycles (phenology).
Salinity Management
No Florida Recommendations!

7. Close spacing/Tree precocity
Conventional grove: 15 x 25 ft.
(116 trees/acre)
Modern grove: 10 x 20 ft
(218 trees/acre)
High density grove: 8 x 15 ft
(363 trees/acre)

8. Lemon/RL planted 5 x 16 ft. Trees were planted on shallow ridges and produced ~ months, 36 months and 800 in 2005.

12. Will the system work…….in Florida?
Sandy soil
Florida rainfall vs. root concentration
How is this system different from what we are already doing?
General economics.
Fruit quality.
Excessive flushing?

13. Rock Bottom OHS/APS Comparisons
10 acre grove in Ft. Pierce
Cooperators – Dr. Bill Castle & Japie Kruger

14. Rock Bottom OHS/APS Comparisons
Ray Ruby, Rio Red, Flame Grapefruit, and Minneola – Gpft 11/06, Minneolas 2/07
Minneola Rootstocks:
Sun Chu Sha
Swingle
Gou Tou
Grapefruit rootstocks:
Smooth Flat Seville
Flying Dragon Trifoliate
Cleopatra Mandarin
X639
US 897

15. Rock Bottom OHS/APS Comparisons
Tree spacing 6 and 8 feet in 20’ rows (363 and 272 trees/acre)
Drip vs. Microjet
Winder/Chobee soils
Saline canal water
Greening all around

16. January 2007 – 2 months after Planting

17. Drip - Ray Ruby/SFS @ 9 Months

18. Microjet – Ray Ruby/SFS @ 9 Months
Granular Slow Release Fertilizer, plus run system every day with liquid fertilizer

20. Question: Will Roots Cluster Under Emitters?
Keep roots bathed in nutrient solution
Rapid uptake of injected materials
Moisture stress management

23. Questions: Can we control tree size? Rootstocks Pruning Fruit
Tree Manipulation
Flowering Control

26. Questions: What is the best spacing?
Canopies touching in 24 months = 1st crop as high as possible
Ray 8’
Minneola/Gou 6’
Spacing will be scion/rootstock/soil dependent.

27. Questions: Profitable? Higher cost/acre for establishment
Much lower cost/tree than “conventional” = earlier operating profit
Lower irrigation, fertilization, weed control, routine labor costs
Higher pruning costs
High production in early years
80% Less Water and Fertilizer Year 1 & 2 – CHEAP!

31. Experiments Under Way Rock Bottom – Dr. Bill Castle and Pete
SWFREC – Dr. Kelly Morgan
CREC, Gapway Groves – Dr. Arnold Schumann
USDA Picos Road – Dr. Ed Stover
Conserv – Drs. Castle, Parsons, Morgan
More planned – GeoSpider?
-- Looking good so far --

32. Why? Whatever the solution to Greening, it will involve new groves
Valid approach even with current knowledge base
Early profit will be primary motivator to re-establish the industry

33. It’s Possible! Needs More Work!
ArapahoCitrus.com