In descending order, by date published.
The fragipan is a naturally occurring restrictive soil horizon that virtually stops water movement and root growth through the soil. It is commonly located 18-32 inches below the surface of most of Kentucky's fragipan soils. The dense nature of this layer is due to the cementation and binding of the soil particles with a silicate rich amorphous aluminosilicate in association with iron. The binding agents seal the pores and pack soil particles close together. The fragipan is found in 2.7 million acres in Kentucky, and about 50 million acres in the United States.