LOCATION RIVERTON OK+MOEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Mollic Paleudalfs
TYPICAL PEDON: Riverton gravelly loam--rangeland.
(Colors are for moist soil unless otherwise stated.)
A1--0 to 7 inches; dark brown (10YR 3/3) gravelly loam, moderate medium granular structure; slightly hard, friable; about 20 percent gravel, 2 mm to 25 mm in diameter; medium acid; gradual smooth boundary. (7 to 12 inches thick)
B1--7 to 18 inches; reddish brown (5YR 4/4) gravelly clay loam, moderate fine subangular blocky structure; slightly hard, friable; about 30 percent gravel, 2 mm to 25 mm in diameter; medium acid; gradual smooth boundary. (8 to 12 inches thick)
B21t--18 to 34 inches; reddish brown (5YR 4/4) gravelly clay loam, moderate fine subangular blocky structure; hard, firm; patchy clay films on faces of peds and surfaces of pebbles; about 40 percent gravel, 2 mm to 80 mm in diameter; strongly acid; gradual wavy boundary. (7 to 16 inches thick)
B22t--34 to 44 inches; dark red (2.5YR 3/6) very gravelly clay loam, moderate fine blocky structure; hard, firm; patchy clay films on faces of peds and surfaces of pebbles, about 50 percent gravel, 2 mm to 80 mm in diameter; strongly acid; gradual smooth boundary. (8 to 20 inches thick)
B31--44 to 64 inches; yellowish red (5YR 4/6) very gravelly clay loam, weak fine blocky structure; hard, firm; about 75 percent gravel, 2 mm to 80 mm in diameter; strongly acid; gradual smooth boundary. (12 to 36 inches thick)
B32--64 to 70 inches; yellowish brown (10YR 5/6) very gravelly clay, many medium prominent red (2.5YR 5/6) and distinct gray (10YR 5/1) mottles; weak fine blocky structure; very hard, firm; about 80 percent gravel, 2 mm to 80 mm in diameter; strongly acid.
TYPE LOCATION: Mayes County, Oklahoma; about 3 miles southwest of Pensacola. 1,320 feet north and 1,220 feet west of the southeast corner of sec. 4. T. 22 N., R. 20 E.
RANGE IN CHARACTERISTICS: Solum thickness is more than 60 inches. Fragments 2 mm to 80 mm in diameter comprise 6 to 30 percent in the A and B1 horizons and 35 to 90 percent of the B2t and B3 horizons. The gravel consists predominately of rounded chert, limestone, or sandstone. Where the A and upper B horizons have moist values and chromas of 3.5 or less the combined thickness is less than 10 inches, or they have less than 50 percent base saturation in some part of the Bt horizon.
The A1 horizon is very dark grayish brown (10YR 3/2), dark brown (10YR 3/3; 7.5YR 3/2), dark yellowish brown (10YR 3/4), or dark reddish brown (5YR 3/2, 3/3, 3/4). It is loam or gravelly loam. Reaction ranges from slightly acid through strongly acid.
The B1 horizon is dark brown or brown (10YR 3/3, 4/3; 7.5YR 4/4) through dark yellowish brown (10YR 4/4), dark reddish brown (5YR 3/3; 2.5YR 3/4) through yellowish red (5YR 4/6) or red (2.5YR 4/6). It is gravelly loam or gravelly clay loam. Reaction ranges from medium through very strongly acid.
The B21t horizon is dark yellowish brown (10YR 3/4, 4/4), brown or dark brown (7.5YR 4/4), dark reddish brown (5YR 3/4; 2.5YR 3/4), through yellowish red (5YR 4/6) or red (2.5YR 4/6). It is gravelly clay loam or very gravelly clay loam. Reaction ranges from medium acid through very strongly acid.
The B22t horizon is brown or dark brown (7.5YR 4/4), dark reddish brown (5YR 3/4; 2.5YR 3/4), through yellowish red (5YR 5/6) or red (2.5YR 5/6). It is very gravelly clay loam or very gravelly silty clay loam and is strongly acid or very strongly acid.
The B3 horizon is yellowish brown (10YR 5/4, 5/6), brown or dark brown (7.5YR 4/4) through strong brown (7.5YR 5/6), reddish brown (5YR 4/4; 2.5YR 4/4) through yellowish red (5YR 5/6) or red (2.5YR 5/6). It is very gravelly clay loam or very gravelly clay and is strongly or very strongly acid.
COMPETING SERIES: These are the Craig, Eldon, Eldorado, Macon, Olpe, and Sallisaw series. Craig and Olpe soils contain more than 35 percent clay in the control section. In addition, Olpe soils have a mollic epipedon. Eldon soils have contrasting textures in the control section and have mean annual soil temperature of less than 59 degrees F. Eldorado soils have a mollic epipedon between 10 and 24 inches thick and the base saturation of more than 50 percent throughout the Bt horizon. Macon and Sallisaw soils lack 35 percent fragments in the control section and have moist values of 4 or more in the A horizon.
GEOGRAPHIC SETTING: Riverton soils are on very gently sloping to gently sloping uplands. They formed in gravelly sediments. Slopes range from 1 to 5 percent. The average annual precipitation ranges from 37 to 47 inches, the annual Thornthwaite P-E indices range from 64 to 80, and the average annual temperature ranges from 59 degrees to about 62 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Craig and Sallisaw series and the Bates and Dennis series. Bates and Dennis soils lack 35 percent fragments in the control section. In addition, Bates soils are underlain by sandstone between depths of 20 and 40 inches and Dennis soils have wetness mottles and contain more than 35 percent clay in the control section.
DRAINAGE AND PERMEABILITY: Well drained; slow to moderate runoff; moderate permeability.
USE AND VEGETATION: Soils are cropped to grain sorghum, soybeans, wheat, and corn; or used for pasture or range. Native vegetation was mainly tall grass.
DISTRIBUTION AND EXTENT: Northeastern Oklahoma, eastern Kansas and southwestern Missouri. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Salina, Kansas
SERIES ESTABLISHED: Cherokee County, Kansas; 1912.
REMARKS: Riverton soils were formerly classified in the Reddish Prairie great soil group.