MISSISSIPPI STATE -- Erosion is more than an unsightly nuisance because if left unattended, it can wash away vast amounts of soil.

Larry Oldham, extension soil specialist at Mississippi State University, said erosion is simply soil being moved by water or wind. Some degree of erosion occurs nearly everywhere.

"Anytime you scratch up the surface of the soil, you're going to have the potential for erosion if you don't put some type of cover over it," Oldham said.

In Mississippi, wind erosion is sometimes a problem in parts of the Delta. But water erosion can occur wherever vegetation, structures or ground covers do not reduce water's energy.

"The water's energy is the force of the raindrops when they hit the surface and the force of the water as it moves across the surface," Oldham said. "The more energy in the water, the more soil will detach and be carried."

Dr. David Nagel, MSU extension horticulturist, said erosion is prevented by not letting raindrops strike bare ground. Structure, vegetation and ground covers break rain's energy.

Common areas where erosion is a problem are construction sites, new roadsides and unprotected soil hit by flowing water.

"Any place you don't have a good grass cover, you have the potential to lose soil," Nagel said.

Water pouring off roofs or charging through ditches can cut a large hole in the soil. Prevent erosion by placing cement, stones or something hard which the water will strike before flowing on.

"Once the energy of the water has been reduced, it can flow over a lawn all the time and never move soil," Nagel said.

Nagel said new roadsides or bare slopes can lose up to three inches of topsoil in one major rainstorm. To prevent the soil from washing away, state and federal laws mandate the use of silt fences along the vulnerable areas.

Any soil that washes away is caught by these fences and can be replaced. Afterwards, grass is established by seeding the area and covering it with straw or cloth, or using hydromulch, which is seed mixed with wood pulp and water and sprayed over the area.

In either case, the rain drops are prevented from directly striking the bare ground and loosening soil so it can wash away.

At new construction sites, the topsoil is commonly scraped off and set aside. Any soil erosion that occurs during construction is of subsoil, which can be replaced, but causes other problems when it washes away.

After construction is complete, the topsoil is spread out again and the area is immediately covered either with sod, or seed and straw.

Soil erosion also usually is not a problem in gardens. Although a garden requires that bare ground be exposed and the soil loosened, plants are soon established and protect the soil from erosion.