LOCATION PURDIN MOEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Oxyaquic Hapludalfs
TYPICAL PEDON: Purdin loam - on a 13 percent convex slope in pasture. The pedon is from an eroded unit. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 7 inches; very dark grayish brown (10YR 3/2) loam, grayish brown (10YR 5/2) dry; moderate very fine granular structure; friable; many fine roots; some mixing of brown (10YR 4/3) peds from underlying horizon; slightly acid; 1 percent gravel; abrupt wavy boundary. (6 to 9 inches thick)
Bt1--7 to 13 inches; dark yellowish brown (10YR 4/4) clay loam; moderate very fine subangular blocky structure; firm; common fine roots; common faint clay films on faces of peds; 1 percent gravel; slightly acid; clear smooth boundary.
Bt2--13 to 18 inches; dark yellowish brown (10YR 4/4) clay loam; moderate fine and very fine subangular blocky structure; firm; common fine roots; many distinct clay films on faces of peds; common medium faint yellowish brown (10YR 5/4) Fe masses in ped interiors; 1 percent gravel; strongly acid; clear smooth boundary.
Bt3--18 to 25 inches; yellowish brown (10YR 5/4) clay loam; moderate fine subangular blocky structure; firm; few fine roots; common prominent clay films on faces of peds; common medium distinct light brownish gray (10YR 6/2) Fe depletions on faces of peds and common medium distinct yellowish brown (10YR 5/6) Fe masses in ped interiors; few fine black concretions (oxides); 2 percent gravel; very strongly acid; gradual smooth boundary.
Bt4--25 to 37 inches; yellowish brown (10YR 5/6) clay loam; moderate medium prismatic structure parting to moderate fine subangular blocky; firm; few fine roots; few faint clay films on vertical faces of peds; many medium and coarse prominent light brownish gray (10YR 6/2) Fe depletions on faces of peds and common medium faint dark yellowish brown (10YR 4/6), and few medium distinct yellowish brown (10YR 5/4) Fe masses in ped interiors; common fine black concretions (oxides); 2 percent gravel; moderately acid; gradual smooth boundary. (Combined thickness of the Bt horizon is 20 to 36 inches.)
Bk1--37 to 50 inches; yellowish brown (10YR 5/6) clay loam; moderate medium prismatic structure parting to weak fine subangular blocky; very firm; few fine roots; many medium and coarse prominent light brownish gray (10YR 6/2) Fe depletions and few medium distinct yellowish brown (10YR 5/4) and few medium faint dark yellowish brown (10YR 4/6) Fe masses in ped interiors; common soft black stains (oxides); 2 percent gravel; few soft masses of calcium carbonate; strong effervescence; moderately alkaline; gradual smooth boundary. (0 to 15 inches thick)
Bk2--50 to 77 inches; variegated yellowish brown (10YR 5/6), dark yellowish brown (10YR 4/6), and light brownish gray (10YR 6/2) clay loam; weak medium prismatic structure; very firm; few black stains (oxides); 2 percent gravel; common soft masses of calcium carbonate; strong effervescence; moderately alkaline.
TYPE LOCATION: Linn County, Missouri; about 4 miles southwest of Browning; 1,520 feet south and 2,575 feet west of the northeast corner, Sec. 15, T. 60 N., R. 21 W.
RANGE IN CHARACTERISTICS: Soft masses of calcium carbonate typically are at depths of 24 to 40 inches.
The Ap or A horizon has hue of 10YR, value of 2 or 3, and chroma of 1 or 2. It commonly is loam or clay loam and in some places silt loam. It is very strongly acid to neutral. Uneroded pedons are assumed to have an E or BE horizon 3 to 5 inches thick.
The Bt horizon has hue of 10YR or 7.5YR, value of 4 to 6, and chroma of 3 to 6. Fe depletions with chroma of 2 are in the lower part. It is clay loam or clay. Reaction is very strongly acid to slightly acid in the upper part and strongly acid to neutral in the lower part.
The Bk horizon has hue of 2.5Y or 10YR, value of 4 to 6, chroma of 1 to 6. It is clay or clay loam in the upper part and clay loam or loam in the lower part. Reaction is slightly alkaline or moderately alkaline.
COMPETING SERIES: This is the Winnegan series. Closely similar soils are in the Gara series. Winnegan soils have value of 4 or more in the Ap horizon or have an A horizon with value of 2 or 3 that is less than 5 inches or less thick. Gara soils are fine-loamy and do not have a saturated layer in the upper 40 inches of the profile.
GEOGRAPHIC SETTING: Purdin soils are on dissected side slopes and on low convex interfluves. These soils formed in glacial till. Slope ranges from 5 to 35 percent. Mean annual temperature ranges from 49 to 54 degrees F, and mean annual precipitation ranges from 32 to 40 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the competing Winnegan and the Armstrong, Lamoni and Pershing soils. Winnegan soils are on similar landscapes. Armstrong and Lamoni soils formed in paleosols and have 2 chroma Fe depletions within 10 inches of the top of the argillic horizon. Pershing soils formed in loess and have 2 chroma Fe depletions within 10 inches of the top of the argillic horizon. These soils are higher on the slope than Purdin soils.
DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is medium to rapid. Permeability is slow. A perched water table has an upper limit of 2.0 to 3.5 feet during November to April.
USE AND VEGETATION: Most areas of Purdin soils are in grass or grass-legume pasture or hayland. A few areas are used for woodland, and some areas are used for wheat, corn, milo, and soybeans. Native vegetation is mixed hardwoods and prairie grasses.
DISTRIBUTION AND EXTENT: Northern Missouri and possibly southern Iowa. The Purdin series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Linn County, Missouri, 1987.
REMARKS: Diagnostic horizons and features recognized in this series are: ochric epipedon - the zone from the surface of the soil to a depth of 7 inches (Ap horizon); argillic horizon - the zone from approximately 7 inches to 37 inches (Bt horizon).