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UF Project Helps Florida Vegetable Growers Compete With Mexico

Waldemar Klassen, (305) 246-7001, ext. 257
Aref Abdul-Baki, (301) 504-5057
Herb Bryan, (305) 246-7001, ext. 280
Yuncong Li, (305) 246-7001, ext. 282

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HOMESTEAD, Fla.—Florida vegetable growers hurt by competition from Mexico can benefit from a system being developed by the University of Florida’s Institute of Food and Agricultural Sciences in collaboration with the U.S. Department of Agriculture to reduce production costs while protecting the environment.

“It’s a do or die situation,” said Waldemar Klassen, an entomologist based at UF’s Tropical Research and Education Center in Homestead. “Our growers are going broke.

“Since 1990, Florida has lost one-third of its U.S. vegetable sales to Mexico,” Klassen said. “Mexican growers undercut our prices. We want to turn the tables.”

Klassen and other researchers are developing a crop production system to reduce Florida growers’ costs. Initial efforts have focused on Dade County’s tomato industry, but Klassen said the system could be used statewide for tomato, bell pepper, cucumber, eggplant and squash.

Aref Abdul-Baki, a research plant physiologist with the USDA, said the system emphasizes environmental protection and economic sustainability.

“Because Florida’s ecosystem is so fragile, we’re using biological methods to enhance crop production, and reducing reliance on synthetic chemicals,” Abdul-Baki said.

He said the project’s main goal was helping Florida growers survive without methyl bromide, a popular soil fumigant used to control nematodes and other pests. By international agreement, methyl bromide will be banned in the United States by 2005. Mexico will use methyl bromide until 2015.

“Trap crops” such as Sunn hemp, velvet bean and cowpea can replace soil fumigants, Abdul-Baki said. Grown during summer months before vegetables are planted, trap crops interfere with the growth of nematodes and reduce their populations so that the main crops escape damage.

“Trap crops block the development of the pests but pose no environmental threat,” he said. “And they’re less expensive than chemical pesticides.”

In a recent demonstration, UF researchers planted tomatoes in soil treated with velvet bean, cowpea or methyl bromide, Abdul-Baki said. Growth, flowering and fruit set were almost identical for all three groups of tomato plants.

Trap crops could replace expensive plastic mulches in South Florida, as they have in temperate areas, said Herb Bryan, a vegetable crops specialist at the Homestead center. By mowing or flattening trap crops, growers can produce organic mulch to protect soil from heat and weeds.

“We’re not ready to abandon plastic mulch yet, but organic mulch has some definite advantages,” Bryan said. “It decomposes over time, retains moisture and binds pesticide residues. Most importantly, it releases nutrients that feed crops and beneficial soil microbes.”

Additional nutrients can be supplied by compost, rather than chemical fertilizer, he said. Bryan developed a process that uses yard waste and food waste to produce compost with safe levels of heavy metals, a concern associated with sewage sludge composting.

Bryan said growers can increase yields using double rows of plants on crop beds. Short-stature tomato plants grown in double rows produced 40 percent more fruit without using additional resources.

Florida’s ongoing drought has made irrigation critical for vegetable production. Yuncong Li, a plant nutrition specialist at the Homestead center, said many growers actually reduce yields by over-irrigating.

Using devices called tensiometers to measure soil moisture, Li found that tomato yields doubled when he irrigated 20 to 50 percent less than local growers. He said excessive irrigation wastes money and water, washes away fertilizer and weakens plant roots.

“Many growers have the attitude, ‘when in doubt, irrigate,'” Li said. “Tensiometers eliminate the doubt.”

But with crops at stake, many growers are skeptical about reducing irrigation, he said.

“Seeing is believing,” Li said. “Last year for a demonstration we split a field with a local tomato grower. He used his irrigation techniques, we used tensiometers. A month later, when he saw our results, he cut back on irrigation.”

More elaborate demonstrations are scheduled this year. Li said UF researchers need to test the system under more challenging conditions, such as high densities of weeds and soilborne pests.

“Our research will continue for two or three years,” he said. “Even though we’re fine-tuning the system, growers can benefit now.”

Li said the UF researchers are seeking grants from the USDA and other agencies to hire additional personnel needed to perfect the production system before methyl bromide is withdrawn.