Approximately 25,000 acres (10,000 hectares) of rice are grown each summer in the Florida Everglades Agricultural Area, which covers an area of about 1,100 square miles (2,800 square kilometers) south of Lake Okeechobee.
Farming here requires a delicate touch. The area has lost about 6 feet (1.8 meters) of soil in the last century through a process called subsidence.
One way to slow this subsidence and preserve nutrient-rich soil is to flood the area during Florida’s rainy season and use the fields to grow rice. The fields are flooded using water from adjacent canals. When the water dries up or seeps out, the rice is harvested.
The Conversation asked Associate Professor Jehangir Bhadha, a soil sustainability expert at the University of Florida, how the university got involved in rice farming and what environmental benefits it provides.
What is the history of growing rice in the Everglades?
Rice was briefly grown in the Everglades Farmland in the 1950s, but the area was limited to about 2,000 acres (800 ha).
Later, a rice virus called hoja blanca, or white leaf, was discovered in Florida and stunted or even killed the plants. This virus was first reported in Colombia and Venezuela in the late 1950s.
Rice returned to Florida in 1977 after growers in the Everglades Agricultural Area demonstrated that it could be grown in sugar cane fields during the summer fallow period from May to August, when the weather in South Florida is too hot and humid to grow vegetables. By this point, hoja blanca disease had been controlled and new resistant rice varieties had been developed.
During the late spring and summer months, more than 50,000 acres (20,000 hectares) of fallow sugarcane land in the Everglades Agricultural Area can be used for rice production. By 2023, about half of these acres were planted to rice. The remaining land either remains fallow or is flooded but does not yield rice—a practice commonly referred to as “fallow flooding”.
On average, 2 tons (1,800 kilograms) of rice are produced from each acre planted.
What makes rice cultivation different in this region?
Rice cultivation in the Everglades Farmland does not need any initial nitrogen, phosphorus or potassium fertilization because regional soils are highly organic and nutrient-rich.
The area consists of approximately 450,000 acres (180,000 hectares) of organic soils known as Histosols. These soils contain up to 80% organic matter, making them unique to the area and a vital resource for its vibrant agricultural economy. Histosols are sometimes called bog or peat soils.
Histosols in South Florida were formed over several thousand years by the accumulation of organic matter faster than the rate of decomposition in flooded reed meadows that developed in the region south of Lake Okeechobee.
But since the soils here were drained for crop production in the early 1900s, organic matter has been decomposing faster than it is being replaced. This is primarily due to microbial-mediated oxidation, which occurs when organic matter is slowly broken down and consumed by microbes, resulting in the gradual loss of soil and lowering of surface elevation.
The soil depth in this area varies from a few inches to 5 feet. The Histosols are underlain by hard limestone bedrock that is not suitable for farming. In many places the limestone bedrock is exposed at the surface or fragments are mixed into the soil.
How does growing rice there contribute to soil health?
By flooding these fields for long periods of time, growers suppress both microbial activity that causes oxidation and pest hatching. They also increase the water-holding capacity of the soil, allowing it to retain more moisture during drier times of the year.
Improved soil health benefits the sugarcane crop and maximizes soil life.
Rice grown underwater also attracts water birds such as the great white heron, snowy egret and glossy ibis.
What does your team do right now?
More rice and more varieties have been planted in the past 15 years. In 2008, only two dominant varieties were planted on about 12,000 acres (4,800 hectares), while by 2023, more than 10 varieties were planted on 23,000 acres (9,300 hectares).
To ensure a steady supply of new varieties, researchers at the University of Florida Institute of Food and Agricultural Sciences and others, along with Florida Rice Growers Inc., conduct annual rice variety trials to rate new or existing varieties in South Florida. The trials aim to identify high-yielding, disease-resistant rice varieties adapted to the region’s subtropical climate and high organic soils.
Each summer, the University of Florida IFAS Extension and its research staff host a rice field day to showcase their current research.
The next rice field day is August 8, 2024 at Belle Glade. Open to the public with advance registration.
This article is republished from The Conversation, a nonprofit, independent news organization that brings you facts and analysis to help you understand our complex world.
Written by: Jehangir Bhadha University of Florida.
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Jehangir Bhadha receives funding from NSF, USDA, FDACS, and Florida Rice Growers Inc.