New research from the American Society of Agronomy reports that the Everglades are sinking. According to scientists who have been studying the unique landscape for over 65 years, soil subsidence, which refers to the sinking or settling of the earth’s surface, as been affecting the Everglades at a rate of approximately 1 inch annually.
The Everglades play an important role in Florida’s tourism industry, but even more important is the role these swampy wetlands play in the sequestration of carbon. The Everglades are composed of a biomaterial called peat, which refers to waterlogged, decomposing plant and animal materials. Compared to other types of soil, peat stores a huge amount of carbon. Through this type of carbon sequestration, peatlands like the Everglades help to reduce the effects of global warming.
So, as you can deduce, when soil subsidence occurs due to agricultural draining as in the case of the Everglades, all that carbon has to go somewhere. And where does it end up? Yes, the atmosphere.
"It's not easy to picture a soil that disappears," says Andes Rodriguez, a researcher at the University of Florida. "The most challenging process I have to explain -- and the most striking -- is how carbon in the soil goes from the soil to the atmosphere." This process, in turn, releases greenhouse gases that warm the planet, Rodriguez elaborates.
The Everglades include an area called in the Everglades Agricultural Area, where 700,000 acres of sugar cane, winter vegetables, and other crops are grown. Rodriguez and other researchers fear that the draining of the Everglades to create agricultural spaces is playing a significant role in the soil subsidence we’re seeing. And the farmers have begun to notice too – some report that the soil is so shallow that they are having difficulties managing water and crops.
So, what can we do to improve soil conservation and explore different water management strategies? "To improve soil conservation, I recommend farmers avoid using short flood cycles," suggests Rodriguez. "I also suggest they use a crop rotation with rice during the summer." These practices decrease the amount of oxygen reaching the soil, which minimizes decomposition. Additionally, he says that farmers can introduce increased plant material (from sugarcane residue, for example) back into the soil to raise levels of carbon in the soil. "I am aware that the practices I recommend present challenges from the agronomic point of view,” comments Rodriguez, “but I am confident they can be sorted."