A lightweight concrete composition is mixed from cement, sand, water, and organic material, and placed on an area of soil, proximal a body of water, to protect the soil from erosion and the like due to water action. Preferably, the organic material comes from the area in which the soil is being stabilized, and may include soil, leafy matter, and ground up wood, forming a particulate organic material. Preferably, the final density of the resulting lightweight concrete composition is greater than the density of the water in the body of water, and less than the density of the soil being stabilized. A representative density range is between 62.43 pounds per cubic foot and 100.00 pounds per cubic foot.