US: Scientists look for alternatives to water for crop freeze protection

Sinkholes that developed in part because of heavy groundwater pumping by farmers protecting their crops in January have helped spawn a research project by University of Florida scientists.

Jack E. Rechcigl, director of the Gulf Coast Research and Education Center in Balm, said his team will be looking at several alternatives for farmers to protect their crops from freeze damage. A safe alternative is needed in light of the damaging effects that sinkholes caused to public and private property this year, Rechcigl said.

For the about the last 40 years farmers have relied on using millions of gallons of water from deep wells to coat strawberry fields with a layer of ice when the temperatures drop below freezing. As long as the deep well water is continuously applied the blossoms and immature berries will be protected. In January, 12 straight nights of freezing temperature forced farmers to spray more than 1 billion gallons of water on their crops.

One of the alternatives the research center task force is looking at as a frost protection measure is hoop tunnels, a non-permanent structure covered with plastic that could be erected in the fields to protect the strawberries during a freeze event.

Assistant professor Bielinski Santos, a horticultural scientist at the research center, said it is possible that the estimated 8,000 acres of strawberry fields in eastern Hillsborough County could be protected from freeze damage.

"Hoop tunnels have proven to be very effective," Santos said. "That is the way strawberries are grown all around the world."

Other options are considered, he said.

"We are also looking at foam, roll covers, low volume sprinklers and intermittent irrigation. We want to provide the grower proven methods from which they can pick and choose. One of the components in my program is to provide the grower with the most economic method."

Foam would be applied to the field by tractors or mechanical sprayers. Roll covers are large insolated blankets that would be applied above the crop.

Santos said the research center is receiving support from the Southwest Florida Water Management District on testing low volume sprinklers as a freeze protection measure.

"More testing is needed in the field," Santos said. "We are looking for a cost effective methods that will provide protection without breaking the bank."