The summer moisture deficit is about 4 inches. These are the competing Sacul soils and the Betis , Bowie , Briley , Ruston , and Woodtell soils. The Betis and Briley soils are in similar positions, have thick sandy epipedons, and loamy particle size control sections. The Bowie and Ruston soils are in similar positions and are fine-loamy. The Woodtell soils are on lower side slopes and have a base saturation that is greater then 35 percent at a depth of 50 inches below the top of the argillic horizon.
Permeability is moderate and runoff is medium to rapid.
Most areas are in woodland. Forest vegetation includes loblolly and shortleaf pines, hickory, southern red oak, sweetgum, and other hardwood trees. The series is of small extent. The Mahan soils were formerly included with the Kirvin series. The series name was taken from that of a small community in Claiborne Parish, Louisiana.