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Rice Industry And Consumers Reap Benefits Of Adding Silicon In Soils

Sylvia Beauchamp

Lawrence Datnoff (561) 996-3062

BELLE GLADE—Instead of using expensive pesticides to control crop diseases, South Florida rice growers can save thousands of dollars in production costs and boost yields simply by adding some silicon to the soil.

The change means, among other things, better quality rice for consumers worldwide.

Tests by researchers at the University of Florida’s Institute of Food and Agricultural Sciences show that increasing soil levels of silicon for rice controls several diseases and increases yields at the same time.

“Silicon is far more effective than chemical fungicides alone,” said Lawrence Datnoff, plant pathologist at UF’s Everglades Research and Education Center in Belle Glade. “When it comes to controlling diseases, no single registered fungicide has such a broad spectrum of activity.”

He said the naturally-occurring soil element controls several major rice diseases such as sheath blight, grain discoloration and rice blast — diseases that usually require more than one fungicide to control.

“Rice growers could save themselves more than a half-million dollars annually in fungicide costs by increasing silicon levels in the soil,” Datnoff said. “We’ve also measured yield increases ranging from 30 to 60 percent. Silicon also allows growers to produce rice in a more environmentally sound system, and the natural material provides consumers with a higher quality product.”

In Florida, where rice is grown mostly as a rotational crop with sugarcane in the Everglades agricultural area, increasing silicon levels in the organic soil can help growers better manage the rate and number of applications of fungicides. The Florida research has major implications for other rice production areas with similar soils such as Africa, Asia, South America and the southeastern United States. A staple food in many areas around the world, rice is grown in 42 countries. The United States ranks tenth in world rice production.

“In today’s competitive market, it is important to optimize inputs to boost yields. A silicon-enhancement system can help rice growers do that,” Datnoff said. “This practice could also benefit other parts of the world where rice is produced on low-silicon soils or where practices lead to silicon depletion in soils.”

Silicon also can help control certain insects and may help plants better utilize other nutrients such as phosphorous, allowing growers to better manage insecticides and fertilizers, Datnoff said.

“If growers worldwide use this material on the appropriate soils, they can reduce their use of fungicides and affect environmental quality. It’s good environmental stewardship to look for alternatives, considering people’s concerns with the use of fungicides and other pesticides and their effects on land and water quality,” Datnoff said.

Much of the organic soil found in Florida’s rice producing area south of Lake Okeechobee contains very small amounts of mineral matter and silicon. To develop cultural and biological methods for increasing disease resistance under Florida soil conditions, silicon studies in rice production were initiated at the Everglades research center and in growers’ fields in 1979. Now, Datnoff said, cooperative research at international agencies and universities in countries such as Brazil and Colombia is beginning to show similar results.

As part of the studies in Florida, Klaus Sengelmann, vice president and general manager of Sem-Chi Rice Products near Belle Glade, is using silicon on more than 16,000 acres of rice in South Florida. He said that without the addition of silicon in integrated pest management practices, rice plants are more susceptible to fungal infections and yields can be 30 percent lower.

“The quality of the rice grain improves considerably, the milling of the grain improves and the grain is more white in color,” Sengelmann said. “There is a definite market advantage for growers to apply silicon, which provides a healthier plant and better grain appearance.”

Rice is planted in Florida in March, with the first harvest in July and the second cutting, or ratoon, ending in November. With more than 20,000 acres in Florida in rice production, Sengelmann said the acreage could double or triple as new federal farm bills could provide a more competitive market, more incentives for growers to produce and better prices for consumers.

“In such a demanding marketplace, Florida needs the best product possible to compete with other southern states alone,” Sengelmann said. “Further research on the organic soils in the Everglades could also apply to similar soils worldwide. We’re still looking at the lasting effects of silicon applications, which may also provide an advantage for crops planted in soils after rice. Those crops should show better yields because of the residual effects silicon may have in the soil.”