LOCATION HANKINS OR

Established Series
Rev. ELD/AON/TDT
02/2013

HANKINS SERIES

The Hankins series consists of deep and very deep, well drained soils that formed in residuum and colluvium from rhyolite and tuff with ash in the upper part. Hankins soils are on hills and have slopes of 1 to 70 percent. The mean annual precipitation is about 23 inches and the mean annual temperature is about 42 degrees F.

TAXONOMIC CLASS: Fine, smectitic, frigid Vertic Palexerolls

TYPICAL PEDON: Hankins ashy silty clay loam, woodland. (Colors are for moist soil unless otherwise noted.)

Oi--0 to 1 inch; slightly decomposed needles and twigs.

A1--1 to 6 inches; very dark brown (10YR 2/2) ashy silty clay loam, grayish brown (10YR 5/2) dry; weak thin platy structure parting to moderate fine granular; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots; common fine irregular pores; slightly acid (pH 6.4); abrupt smooth boundary. (3 to 8 inches thick)

A2--6 to 11 inches; very dark brown (10YR 2/2) ashy silty clay loam, grayish brown (10YR 5/2) dry; strong fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic; common very fine roots; few fine and common very fine tubular pores; neutral (pH 6.6); abrupt smooth boundary. (4 to 11 inches thick)

2Bt1--11 to 17 inches; very dark brown (10YR 2/2) clay, brown (10YR 4/3) dry; weak medium prismatic structure parting to moderate fine and medium blocky; extremely hard, very firm, very sticky and very plastic; common very fine and fine roots; few fine and common very fine tubular pores; continuous distinct clay films or pressure faces on faces of peds; neutral (pH 6.6); clear smooth boundary. (5 to 10 inches thick)

2Bt2--17 to 28 inches; dark brown (10YR 3/3) clay, brown (10YR 5/3) dry; weak medium prismatic structure parting to moderate subangular blocky; very hard, very firm, very sticky and very plastic; common very fine and fine roots; few fine and very fine tubular pores; continuous distinct very dark grayish brown (10YR 3/2) clay films on faces of peds; neutral (pH 6.6); clear smooth boundary. (5 to 15 inches thick)

2Bt3--28 to 36 inches; brown (10YR 4/3) clay, brown (10YR 5/3) dry; moderate medium subangular blocky structure; very hard, very firm, very sticky and very plastic; few fine roots; common very fine tubular pores; common distinct dark yellowish brown (10YR 3/4) clay films in pores and few faint on faces of peds; slightly acid (pH 6.4); gradual wavy boundary. (0 to 15 inches thick)

2Bt4--36 to 46 inches; brown (10YR 5/3) clay, very pale brown (10YR 7/3) dry; moderate medium and fine subangular blocky structure; slightly brittle when moist, crushes with moderate pressure; very hard, firm, moderately sticky and moderately plastic; few fine roots; few fine tubular pores; few thin brown (10YR 4/3) clay films on peds and common distinct clay films in pores; moderately acid (pH 6.0); gradual wavy boundary. (0 to 15 inches thick)

2Bt5--46 to 55 inches; brown (10YR 5/3) clay, very pale brown (10YR 7/3) dry; moderate fine and very fine subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; few fine roots; few fine and very fine tubular pores; common distinct brown (10YR 4/3) clay films in pores; neutral (pH 6.8).

TYPE LOCATION: Grant County, Oregon; 8 miles north of Dayville on Franks Creek road; on section line and 1,570 feet south of NW corner of sec. 33, T. 11 S., R. 27 E. Latitude - 44 degrees, 34 minutes, 27 seconds North; Longitude - 119 degrees, 29 minutes, 19 seconds West.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 42 to 47 degrees F. The soils are usually moist but are dry between depths of 4 and 12 inches for 60 to 90 consecutive days during the summer. Depth to bedrock is 40 to more than 60 inches. When bedrock is present it is paralithic. The mollic epipedon is 20 to 40 inches thick. Base saturation throughout the solum is 75 to 95 percent by sum of bases. The solum is neutral to moderately acid.

The A horizon has value of 3 through 5 dry, 2 or 3 moist and chroma of 1 thru 3 moist and dry. It is ashy silt loam, ashy loam or ashy silty clay loam. The change in texture to the argillic horizon is abrupt with an absolute increase in clay of 15 to 20 percent. It is 7 to 14 inches thick and has 15 to 40 percent glass and acid oxalate aluminum plus one-half the acid oxalate iron is 0.2 to 0.5 percent. It has 0 to 40 percent gravel, 0 to 30 percent cobbles and 0 to 10 percent stones.

Some pedons have a 3 to 8 inch thick Bw horizon consisting of clay loam or silty clay loam with 30 to 40 percent clay.

The 2Bt horizon has hue of 10YR to 5YR, moist value of 2 or 3 in the upper part, 3 or 4 in the lower part and dry value of 4 or 5 in the upper part and 5 through 7 in the lower part. It is clay or silty clay and has 45 to 60 percent clay. It has weak or moderate prismatic structure parting to moderate or strong subangular or angular blocky. It has 0 to 20 percent gravel, 0 to 30 percent cobbles and 0 to 5 percent stones.

COMPETING SERIES: These are the Booth, Campcreek, Carryback, Crowcamp, Jesh (T), Lacrol, Tippett and Zumwalt series. All of these series lack an O horizon, have a mollic epipedon less than 20 inches thick except Crowcamp and lack vitrandic properties in the surface layer.

GEOGRAPHIC SETTING: Hankins soils are on hills at elevations of from 2,500 to 5,200 feet. Slopes are 1 to 70 percent. These soils formed in residuum and colluvium from basalt, rhyolite and tuff with an influence of volcanic ash in the upper part. The climate is subhumid with a mean annual precipitation of 16 to 30 inches. Mean annual air temperature is 40 to 45 degrees F, mean July temperature is about 58 to 62 degrees F, and mean January temperature is 27 to 32 degrees F. The frost-free period is about 20 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Alding, Boardtree, McGarr, Tolo and Yawkey soils. Alding soils are shallow to bedrock. Boardtree and Tolo have surface soils formed in volcanic ash. McGarr soils are 20 to 40 inches deep to bedrock. Yawkey soils are clayey-skeletal.

DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; slow permeability.

USE AND VEGETATION: Used mainly for timber production and for grazing. Native plants are ponderosa pine, Douglas fir, elksedge and Idaho fescue. This series is characterized by what is called the moist and dry ponderosa pine forest plant communities.

DISTRIBUTION AND EXTENT: East-central Oregon; MLRA 10. The series is extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Trout Creek-Shaniko Area, Oregon; 1970.

REMARKS: Diagnostic horizons and other features:

Xeric moisture regime
Mollic epipedon - 1 to 28 inches
Argillic horizon - 11 to 55 inches
Pale feature - abrupt textural change at 11 inches with an absolute increase in clay content of 20 percent.
Vitrandic feature - (Al + 1/2 Fe x 60) + glass is about 39 from 1 to 11 inches.
Pachic feature - mollic epipedon is 27 inches thick
Vertic subgroup - the calculate LE is over 6.0 centimeters within the upper meter.

The soil has base saturation of more than 75 percent by sum of bases throughout the solum. This is based on several lab. sample pedons.

ADDITIONAL DATA: Reference samples - Umatilla County; 84T7170-7173; 82T7689-7691 and Grant County S74OR-023-001 and S97OR-023-017.

National Cooperative Soil Survey
U.S.A.