Consolidated citrus BMPs still provide for regional flexibility

01/10/2013 04:14:00 PM
Renee Stern

Regional differences in nutrient and water quality management guidelines for Florida's citrus growers will be reduced under a new statewide approach.

This winter's consolidation into a single document of what had been four different regional best management practices manuals will be a boon for growers with groves scattered around the state, says Bill Bartnick, environmental administrator at the Florida Department of Agriculture in Tallahassee.

The change also offers an entry point into the program for growers not previously covered by the older manuals. Enrolling in the BMP program provides growers with a "presumption of compliance" with the state's water quality requirements, Bartnick says. Those growers don't need to monitor water quality and nutrient discharge limits.

Most growers already in the program will see few changes under the new manual; the biggest differences for them are new nutrition recommendations in the University of Florida's publication SL 253, "Nutrition of Florida Citrus Trees."

These growers in the state's Flatwoods areas—covered previously by the Peace River, Indian River and Gulf manuals—otherwise will be grandfathered into the new guidelines, Bartnick says. Between 1,000 and 2,000 citrus operations in the Flatwoods already are enrolled.

Previous BMP guidelines for these areas already were comprehensive, given drainage issues and a high water table.

"They have to worry about too much water as well as no water," says Tom Obreza, interim associate dean for Extension at the University of Florida in Gainesville. "There's more to think about in poorly drained soil in terms of soil and water issues."

Two-year grace period

Growers in the state's well-drained Central Ridge, which will be most affected by the changes, will have a two-year grace period to re-enroll, Bartnick says. With about 100,000 acres in the Ridge currently in the program, getting those growers up to speed on the changes will take some time.

Previously they fell under more streamlined guidelines focused on managing nitrogen and curtailing its leaching into groundwater. The new statewide manual runs 74 pages and covers not just nutrient management but irrigation and drainage management, integrated pest management, and sediment and erosion control.

Some parts of the new, broader checklist—canal care, for instance—won't apply to Ridge growers, Obreza says. Their main concerns are groundwater and nitrogen management, while Flatwoods growers must focus more on surface water and phosphorus management.

"I applaud the state for doing this," says Ray Royce, executive director of the Highlands County Citrus Growers Association. "We don't want to be a negative impactor on water quality. No one has a greater stake in preserving water quality and quantity (than growers)."

The BMP program helps assure the public that Florida's citrus industry uses the most economical and environmentally friendly practices, he says.

More attention to detail

The changes will require more attention to detail and to documenting inputs and practices, Royce says. That extra work will pay off, however, given the increasing demand for growers to keep detailed records on other concerns.

Records also should explain when on-farm conditions such as shallow root profiles or disease symptoms call for diverging from nutrition recommendations, he says.

Some Ridge growers, while agreeing with the changes overall, view the details with some caution. Ned Hancock, a grower in Avon Park, worries about maximum levels for total nitrogen applications.

Growers have adopted new approaches to combat citrus greening, but the nutrition recommendations in the guidelines appear to tie growers to "an antiquated way of looking at nitrogen," Hancock says. "It's a whole new ball game with greening."

A more nuanced approach that differentiates application methods and timing would take into account the adoption of more efficient uses of fertilizers and plant growth products, he says.

But Obreza—a soil and water science Extension specialist who helped edit the newest recommendations—says the BMP nutrition guidelines allow flexibility.

"It's not prescriptive," he says. "They can put nitrogen on any way they want." Application methods matter less than using only as much nitrogen as the tree can use.

Since greening took hold, the industry has outpaced researchers when it comes to adopting new nutrient management techniques such as foliar applications, Obreza says.

Research on foliar nutrient applications so far isn't sufficient to form recommendations, he says. Anecdotal evidence and theories eventually will give way to solid research data.

Nitrogen guidelines

With the manual's nitrogen guidelines tied to the university's recommendations, maximum nitrogen levels will be updated as researchers gain more understanding from testing, he says.

That's separate from periodic revisions to the BMP manual itself, a more involved undertaking roughly every five years.

The new consolidated citrus manual includes those needed updates as well.

One new feature is guidelines on grove rehabilitation and replanting for growers dealing with disease issues. "These are things to think about if you're pushing up trees and moving dirt around," Bartnick says.

The old manuals also didn't touch on protecting water resources such as wetlands, wellheads and streams with riparian buffers, he says. Many groves contain or are adjacent to depressional lakes, which now need to be surrounded by a 50-foot buffer.

"If you're replanting, this is the time to add a buffer," he says.

"This is the best compromise for everyone," says John Smoak III, general manager of Smoak Groves, Lake Placid. Regulators, growers and the environmental community worked together to develop the most workable solution for all sides.

The guidelines not only help protect groundwater but also improve his company's bottom line. "We were able to research how to be more efficient in the use of nutrients," he says. "It made us better farmers."

He's turned to more frequent applications of smaller amounts of nitrogen and other nutrients, and holds off until after heavy rains.

The new BMP manual contains "all common-sense stuff," says Mark Colbert, general manager at A. Duda & Sons Inc., headquartered in Oviedo.

"We don't like to spray or fertilize more than we need and see it leach out," Colbert says. Applications that miss their target also can affect water quality whether they land on standing water or bare ground.

Reading and following the outlined practices is similar to taking a college course in grove management, he says. Even so, "It's not 100 percent complete for everybody. It never will be."

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