How Florida Growers are Fine-Tuning Citrus Fertility

Citrus growers have always scrutinized their plant nutrition programs, but with HLB now in the mix, that scrutiny is on hyperdrive. And the programs are sort of like fingerprints — each different based on individual circumstances. Over the years, growers have honed in approaches that appear to be helping infected trees stay as productive as possible.

Water barrel graphic depicting Liebig's law of the minimum
The barrel depicting Liebig’s law of the minimum has become a common sight in citrus fertilizer presentations.
Graphic courtesy of UF/IFAS

Sharing Insights

In the spirit of open dialogue to help the industry fight the scourge of HLB, many growers are sharing what is working or not in their fertility programs. Once such grower is Marty McKenna who farms with his brother, Pat. He recently spoke at Florida Citrus Mutual’s Citrus Industry Annual Conference on McKenna Bros.’ fertilizer program and its successes.

He began by crediting Maury Boyd for bringing attention to Liebig’s law of the minimum, which states: the rate of growth of a plant, the size to which it grows, and its overall health depend on the amount of the scarcest of its essential nutrients that is available to it.

Both McKenna and Boyd are past winners of Florida GrowerSM magazine’s Citrus Achievement Award.

“Our situation is we are 100% infected with HLB,” McKenna told conference attendees. “We quickly realized we are not going to stay in business if we spent more than we were taking in. So, we had these two issues as we tried to get in the right direction to stay in business.”

McKenna said his brother Pat drove down to visit Ed English’s grove to observe his program of applying micronutrients to the root system, which was appearing to have success.

2016 Florida Grower Citrus Achievement Award winner Marty McKenna
Marty McKenna
Photo by Frank Giles

“As he was driving back, Pat called me and said, ‘Marty, I just saw the prettiest Valencia orange grove I have seen in 10 years,’” he said.
After the visit, the brothers began trying figure out a way to duplicate the program on their groves.

“It is not a one size fits all, but the beauty of minor elements applied on the ground in the presence of greening is anybody can try it,” McKenna says. “I think it is important that you can utilize the equipment you already have in groves with this approach.”

The McKennas have been using fertigation for more than 30 years. This guided their program to deliver minor elements to the roots via fertigation. After a lot of trial and error and tracking, they developed a 5-0-7 mix.

“It is basically an all nitrate fertilizer program,” McKenna said. “We alternate this due to the [Liebig’s law of the minimum] with a 5-4-7 mix, which has the boron, molybdenum, and phosphate. So, we are alternating these applications weekly [weather permitting].”

The program is more expensive than more conventional approaches. McKenna said they were backing off a little on nitrogen and would likely be below 200 pounds per acre, or perhaps even less than 150 pounds per acre given the right conditions. The brothers also are dialing back the intensity of their psyllid control applications to free up dollars for the fertilizer program.
McKenna continues to further supplement trees with a foliar nutrition program.

Hybrid Approach

Understanding the importance of root health and providing a steady source of nutrition, Rob Atchley, General Manager of Groves for Duda Citrus Division, and his team have developed a hybrid fertilizer program that focuses on the benefits of controlled-release fertilizers.

Rob Atchley
Rob Atchley

From 2013 to 2015, Duda put in a number of large plantings. The homogenous prill slow release materials they used were safe enough to put in tree holes at planting and provided a steady source of early nutrition and cut down on leeching.

“By putting it down in the hole, the fertilizer stays right there with the tree, and we’ve had very good luck with,” Atchley says. “Beyond that on the young trees, we use a lot of foliar nutrition, which goes out about every three to four weeks.”

The controlled-release fertilizer and foliar program carried the young trees to about year two. Atchley then moved on to what he calls a hybrid fertilizer approach, which combines conventional fertilizers with controlled-release fertilizers, along with foliar applications. “We apply dry fertilizer at the normal times most growers do (January, April, and October),” he says. “We vary my percentage of controlled-release fertilizer to match the weather patterns for certain times of the year. We also rely heavily on soil and leaf sampling to direct our applications. When you are spending that much on sampling, you don’t really want to use a cookie-cutter approach to fertilization.”

Atchley says the combination of their hybrid fertilizer program and continued strong commitment to psyllid control is paying off in Duda’s groves.

Topics: , ,

Leave a Reply

Citrus Stories
Winter melon damage from Hurricane Irma in Elkton, FL
Citrus
September 15, 2017
Help Extended to Hurricane-Weary Farmers Dealing With Disaster
USDA chief grants extra time and special procedures to document and file claims. Read More
raindrops in standing water
Citrus
September 13, 2017
New Guidance on FSMA Ag Water Compliance, Water Testing, and Farm Inspections Announced
FDA issued a rule to extend compliance dates for agricultural water and announced a start date for farm inspections. Read More
Packinghouse damage from Irma at SWFREC in Immokalee
Citrus
September 13, 2017
Florida Farmers Digging out From Impacts of Irma
Damage reports starting to flood in from the field following monster storm, and it's not pretty. Read More
Biocontrols Conference
September 11, 2017
The Grower’s Take: Citrus, HLB, and Biological Control
Uncle Matt’s Organic orange juice brand has enjoyed steady growth since its 2002 inception. The brand’s success is due to Read More
Citrus
September 7, 2017
Summer News Stories that Have Growers Talking
Farming has been in the media spotlight this year. I asked each of this month’s columnists and contributors for their Read More
Citrus
September 7, 2017
Whose Sustainable Standard Wins?
Retailers’ race to win the most sustainable produce prize leaves growers trying to keep up with fast-developing demands. Read More
Citrus
September 7, 2017
Improving Water Management: Can Silicon Valley Help?
Though very much-needed, technological solutions must be cost-effective and industry appropriate. Read More
Florida oranges
Citrus
August 31, 2017
Extra Early Florida Citrus Forecast Calling For Sunshine
Marked increase in production predicted for the next crop of oranges. Read More
Citrus
August 30, 2017
How Harvey May Impact Specialty Crop Growers
The devastating human toll from Hurricane/Tropical Storm Harvey has rightly dominated news coverage. Growers and those who work with them, however, should also think about how this historic storm will also affect them.  Read More
Insect & Disease Update
August 28, 2017
California Extends Citrus Quarantine
A 94-square mile area of San Bernardino, Riverside counties now a part of state huanglongbing quarantine. Read More
Strawberry fieldworker in Florida
Citrus
August 28, 2017
Specialty Crop Concern Feeds Need to Negotiate NAFTA Now
Although trade talk objectives may not deliver the short-term relief for Florida fruit and vegetable growers, they appear on the right track. Read More
Cannabis plant closeup
Citrus
August 28, 2017
3 More Florida Growers Given Green Light to Cultivate Medicinal Cannabis
Once exclusive enterprise continues to expand for more seeking to engage alternative crop endeavor. Read More
multiple hands holding a plate full of veggies
Citrus
August 27, 2017
USDA Releases Software to Help Small Operations with Food Safety Plans
While the free tool was primarily designed for use by small firms, any size manufacturer can opt to use it. Read More
Workers picking in a Florida strawberry field
Citrus
August 25, 2017
Transcending Farm Labor Crisis No Easy Task [Opinion]
Technology could be on cusp of fixing labor problems for growers of crops that are traditionally hand harvested. Read More
two-spotted spider mite
Citrus
August 25, 2017
California EPA Seeking to Review Chlorpyrifos
Department of Pesticide Regulation, Office of Environmental Health pursuing health protections. Read More
The Latest
Citrus
September 21, 2017
Hurricane Relief Fund Launched for Flori…
Money raised will benefit Redlands Christian Migrant Association’s efforts to aid families in need. Read More
Citrus
September 19, 2017
Precision in Specialty Crops Gains Momen…
Here are some of the key drivers that may transform your farm in the years ahead. Read More
Citrus
September 19, 2017
Hopes High for Hops Fresh From Florida
When it comes to alternative crop solutions, something good is brewing in the Sunshine State. Do you have what it takes to tap in? Read More
Citrus
September 15, 2017
Help Extended to Hurricane-Weary Farmers…
USDA chief grants extra time and special procedures to document and file claims. Read More
Citrus
September 13, 2017
New Guidance on FSMA Ag Water Compliance…
FDA issued a rule to extend compliance dates for agricultural water and announced a start date for farm inspections. Read More
Citrus
September 13, 2017
Florida Farmers Digging out From Impacts…
Damage reports starting to flood in from the field following monster storm, and it's not pretty. Read More
Biocontrols Conference
September 11, 2017
The Grower’s Take: Citrus, HLB, and Biol…
Uncle Matt’s Organic orange juice brand has enjoyed steady growth since its 2002 inception. The brand’s success is due to Read More
Citrus
September 7, 2017
Summer News Stories that Have Growers Ta…
Farming has been in the media spotlight this year. I asked each of this month’s columnists and contributors for their Read More
Citrus
September 7, 2017
Whose Sustainable Standard Wins?
Retailers’ race to win the most sustainable produce prize leaves growers trying to keep up with fast-developing demands. Read More
Citrus
September 7, 2017
Improving Water Management: Can Silicon …
Though very much-needed, technological solutions must be cost-effective and industry appropriate. Read More
Citrus
August 31, 2017
Extra Early Florida Citrus Forecast Call…
Marked increase in production predicted for the next crop of oranges. Read More
Citrus
August 30, 2017
How Harvey May Impact Specialty Crop Gro…
The devastating human toll from Hurricane/Tropical Storm Harvey has rightly dominated news coverage. Growers and those who work with them, however, should also think about how this historic storm will also affect them.  Read More
Citrus
August 28, 2017
Specialty Crop Concern Feeds Need to Neg…
Although trade talk objectives may not deliver the short-term relief for Florida fruit and vegetable growers, they appear on the right track. Read More
Citrus
August 28, 2017
3 More Florida Growers Given Green Light…
Once exclusive enterprise continues to expand for more seeking to engage alternative crop endeavor. Read More
Citrus
August 27, 2017
USDA Releases Software to Help Small Ope…
While the free tool was primarily designed for use by small firms, any size manufacturer can opt to use it. Read More
Citrus
August 25, 2017
Transcending Farm Labor Crisis No Easy T…
Technology could be on cusp of fixing labor problems for growers of crops that are traditionally hand harvested. Read More
Citrus
August 25, 2017
California EPA Seeking to Review Chlorpy…
Department of Pesticide Regulation, Office of Environmental Health pursuing health protections. Read More
Citrus
August 23, 2017
Varroa Mite Researchers Talk High Infest…
In 2016, The New York State Beekeeper Tech Team (which is attached to Cornell University’s Dyce Lab Beekeeping Resources) found that Read More