In Focus: Jerry Southwell

Jerry Southwell_Yara

1. How would you characterize a successful bloom in citrus?

Southwell: A successful bloom results from optimal flower induction weather conditions coupled with a long-term balanced nutritional program to maximize bloom, fruit set, and the fruit-carrying capacity of the tree. Early uniform pollination of flowers yields larger fruit with less variability in size resulting in increased pound solids potential. If the tree is staged for the bloom and early fruit set is accomplished, the potential for premature fruit drop is diminished.

2. How important is proper nutrition in establishing and holding a bloom set in citrus?

Southwell: A healthy tree is the result of proper nutrition derived from the right rate at the right time from the right source. Trees during bloom take up a given amount of nutrients from a potential static supply. It’s static due to the fact that the bloom takes place during the time of the year with the driest and coolest soil conditions, which limit availability and uptake of soil nutrients. Supplemental nutrient addition and irrigation will be needed.

3. In what ways do proper levels of calcium benefit citrus trees and yields?

Southwell: Calcium is often overlooked due to adequate levels reported in most soil test results or leaf tissue. If we examine the calcium content of each flower produced in a normal year (50 to 100,000 flowers), the tree/soil has to provide roughly two to four ounces of calcium per tree just for the blooms. Once the flower has been fertilized and begins the fruit-forming process, it will need nearly 0.2 ounces more calcium per box for the fruit to hold past five weeks. If we assume that 200 pieces of fruit fill a box and if we have five boxes of fruit per tree, that’s another 1 ounce per tree. The total amount of calcium needed in the first five weeks is 24 to 39 pounds. Much of this total will drop back to the ground as aborted flower/fruitlet, but is not available for immediate uptake.

When we have an inadequate supply of available calcium and a bouquet bloom, the sheer number of additional demands upon tree calcium supply drops the fruit calcium content below critical levels and results in a lighter crop than with an average bloom.

Calcium deficiency is partially defined as “death of growing points.” Simply, calcium is needed for cell division or mitosis. In the early spring with bloom and flush representing your photosynthetic capacity and pound solids for your profitability, calcium is greatly needed for development of leaves and fruit.

4. What role does a calcium-based product play in the era of HLB?

Southwell: Calcium and potassium are involved in programmed cell death of pathogens and infected tissue in many plant species. Research is being conducted to determine if this process exists in citrus. We do know that calcium deficient trees are more susceptible to HLB. In some species, calcium can open plugged phloem tubes. These functions have potential in mitigation of diseases such as canker and HLB, but remain unproven in citrus.

Topics:

Leave a Reply

Citrus Stories
citrus psyllid closeup
Insect & Disease Update
February 18, 2017
The War on Citrus Psyllids Still Raging
Despite control challenges, keeping the pest in check remains the best approach to managing HLB. Read More
IMPAC.org screenshot
Citrus
February 17, 2017
How Precision Agriculture Is Helping Farmers Win Over Consumers
New Florida-based organization is seeking to break down barriers between farmers and shoppers by providing a platform to not only show what is grown, but how it's grown. Read More
Brussels Sprout on a fork
Citrus
February 16, 2017
Food Trends Driving Growth Opportunities for Florida Farmers
More niche markets emerging for growers to give consumers what they want and need. Read More
John Merritt
Citrus
February 15, 2017
Florida Citrus Community Loses Longtime Leader to Leukemia
John Merritt, known as an innovative grower and staunch industry advocate, was 60. Read More
Grower Jonathan Brown of Bethel Farms inspects his citrus grove.
Citrus
February 9, 2017
Florida Citrus Forecast Comes Full Circle With Latest Update
Amid up-and-down pattern, USDA puts all-orange production numbers back on target with initial estimate. Read More
Load of pot poorly camouflaged as Key limes
Citrus
February 8, 2017
Nearly Two Tons of Pot Plucked From Load of Key Limes
Shaped to resemble the tangy citrus fruit, law enforcement officials extract 34,764 packages allegedly filled with an ingredient not intended for pies. Read More
Citrus
February 5, 2017
New Product Helps Bees Brush Off Mites
A British company developed Bee Gym, distributed by Vita Ltd. Read More
The Latest
Citrus
February 22, 2017
New Insecticide Available to Combat Suck…
Minecto Pro from Syngenta has received EPA approval for use in specialty and vegetable crops to control lepidopteran and other pests. Read More
Citrus
February 22, 2017
Skilled Labor Needed to Keep Agriculture…
Even with the challenge of feeding a growing global population at hand, has focus been lost on recruiting where jobs on the farm are need most? Read More
Citrus
February 17, 2017
How Precision Agriculture Is Helping Far…
New Florida-based organization is seeking to break down barriers between farmers and shoppers by providing a platform to not only show what is grown, but how it's grown. Read More
Citrus
February 16, 2017
Food Trends Driving Growth Opportunities…
More niche markets emerging for growers to give consumers what they want and need. Read More
Citrus
February 15, 2017
Florida Citrus Community Loses Longtime …
John Merritt, known as an innovative grower and staunch industry advocate, was 60. Read More
Citrus
February 9, 2017
Florida Citrus Forecast Comes Full Circl…
Amid up-and-down pattern, USDA puts all-orange production numbers back on target with initial estimate. Read More
Citrus
February 8, 2017
Nearly Two Tons of Pot Plucked From Load…
Shaped to resemble the tangy citrus fruit, law enforcement officials extract 34,764 packages allegedly filled with an ingredient not intended for pies. Read More
Citrus
February 5, 2017
New Product Helps Bees Brush Off Mites
A British company developed Bee Gym, distributed by Vita Ltd. Read More
Citrus
February 3, 2017
Wonderful Citrus Stakes a Major Claim in…
Acquisition of the largest citrus marketer in Florida makes California company the crop’s top grower, shipper, and packer in the U.S. Read More
Citrus
February 2, 2017
Florida Seeking to Fete More Eco-Innovat…
Nominations open for the Commissioner’s Agricultural-Environmental Award. Read More
Citrus
February 2, 2017
University of Florida Celebrating a Cent…
Cheers all around for UF/IFAS' CREC, the largest facility in the world devoted to a single commodity. Read More
Citrus
January 30, 2017
List of Best College Farms Released
Website evaluated farms on sustainability factors, community programming, and courses available at the university or college farm, not just in the classroom. Read More
Citrus
January 30, 2017
Game Far From Over for Florida Citrus
Attendees of the 2017 Florida Citrus Show convene to commiserate over current challenges, vet future wins via new varieties. Read More
Citrus
January 25, 2017
Ban Lifted on USDA News Releases
Acting USDA deputy administrator says the practice is typical with new administration changes. Read More
Citrus
January 25, 2017
USDA-ARS to Halt Publishing News Release…
News media confirm report. Read More
Citrus
January 24, 2017
Trump Withdraws U.S. From Trans-Pacific …
Fresh produce export market to hit a wall with signing of executive order. Read More
Citrus
January 20, 2017
Farming Will Always Have a Place in Flor…
Growers are resilient and agriculture will survive in our state and elsewhere. It has to, if we want food on our plates. Read More
Citrus
January 19, 2017
Trump Taps Sonny Perdue for Secretary of…
Ag leaders applaud pick to head up USDA. Read More