LOCATION HATROCK            OR
Tentative Series
IRD. TLC/TDT
1/99

HATROCK SERIES


The Hatrock series consists of very deep, well drained soils that formed in colluvium derived from rhyolite and mixed with volcanic ash. Hatrock soils are on north-facing buttes and have slopes of 12 to 30 percent. The mean annual precipitation is about 14 inches and the mean annual temperature is about 43 degrees F.

TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Vitrandic Haploxerolls

TYPICAL PEDON: Hatrock cobbly ashy fine sandy loam, on a 30 percent north slope, rangeland. (Colors are for moist soils unless otherwise noted.)

A--0 to 2 inches; very dark grayish brown (10YR 3/2) cobbly ashy fine sandy loam, brown (10YR 5/3) dry; weak very fine granular structure; soft, very friable, nonsticky and nonplastic; common very fine roots; common very fine interstitial pores; 10 percent sand-size (0.25 to 1.0 mm) pumice; 5 percent stones, 10 percent cobbles and 5 percent gravel; neutral (pH 7.0); clear wavy boundary. (2 to 6 inches thick)

AB--2 to 12 inches; dark grayish brown (10YR 3/2) cobbly ashy fine sandy loam, brown (10YR 5/3) dry; moderate fine subangular blocky structure; slightly hard, very friable, nonsticky and slightly plastic; common very fine and few coarse roots; many very fine tubular pores; 10 percent sand-size (0.25 to 1.0 mm) pumice; 5 percent stones, 10 percent cobbles and 5 percent gravel; neutral (pH 7.2); clear wavy boundary. (8 to 14 inches thick)

Bw--12 to 23 inches; dark brown (10YR 3/3) gravelly ashy fine sandy loam, pale brown (10YR 6/3) dry; weak very fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and few fine and coarse roots; few very fine tubular pores; 15 percent sand-size (0.25 to 1.0 mm) pumice; 5 percent cobbles and 15 percent gravel; neutral (pH 7.2); clear wavy boundary. ( 9 to 13 inches thick)

Bk--23 to 60 inches; dark grayish brown (10YR 4/2) very stony ashy fine sandy loam, light brownish gray (10YR 6/2) dry; single grain; soft, very friable, nonsticky and nonplastic; few very fine and few coarse roots; 15 percent sand-size (0.25 to 1.0 mm) pumice; 15 percent stones, 20 percent cobbles and 20 percent gravel; slightly effervescent with lime on lower side of some rock fragments; slightly alkaline (pH 7.6).

TYPE LOCATION: Crook County, Oregon; located 400 feet east and 2,500 feet south of the NW corner of section 2, T. 16 S., R. 15 E.; about 2 miles southeast of the Three Spring Ranch.

RANGE OF CHARACTERISTICS: These soils are usually moist, but are dry in the moisture control section for 75 to 90 days following the summer solstice. The mean annual soil temperature is 42 to 47 degrees F. Depth to bedrock is greater than 60 inches. Depth to secondary carbonates is 20 to 30 inches. The particle-size control section has 10 to 15 percent field estimates clay and averages 35 to 50 percent rock fragments. The mollic epipedon is 10 to 20 inches thick. The solum has 15 to 25 percent phosphate retention, acid oxalate aluminum plus one-half the iron of 0.4 to 0.8 percent and 30 to 50 percent lass and glass coated aggregate.

The A and AB horizons have value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It contains 5 to 20 percent gravel, 10 to 20 percent cobbles and 0 to 10 percent stones. The sand-size (0.25 to 1.0mm) pumice content ranges from 10 to 20 percent.

The Bw horizon has value of 2 or 3 moist, 5 or 6 dry, and chroma of 2 or 3 moist and dry. It is ashy fine sandy loam or ashy loam and contains 5 to 20 percent gravel, 5 to 20 percent cobbles and 0 to 10 percent stones. The sand-size (0.25 to 1.0mm) pumice content ranges from 5 to 15 percent.

The Bk horizon has value of 3 or 4 moist, 5 or 6 dry, and chroma of 3 or 4 moist and dry. It is ashy fine sandy loam or ashy loam and contains 10 to 30 percent gravel, 20 to 50 percent cobbles and 15 to 40 percent stones. The sand-size (0.25 to 1.0mm) pumice content ranges from 5 to 15 percent It is slightly to strongly effervescent.

COMPETING SERIES: These are the Clearline, Fulcrum, Linecreek, Lonigan and Stines series. Clearline soils have a mollic epipedon 20 to 30 inches thick and are deep to bedrock. Fulcrum and Lonigan soils are moderately deep to bedrock. Linecreek soils are dry for 60 to 75 days. Stines soils are deep to bedrock.

GEOGRAPHIC SETTING: Hatrock soils are on north-facing slopes of buttes at elevations of 3,500 to 5,100 feet. Slopes range from 12 to 30 percent. These soils formed in colluvium derived from rhyolite and mixed with volcanic ash. The climate is characterized by cold wet winters and hot dry summers. The mean annual precipitation is 12 to 16 inches, the mean annual temperature is 40 to 46 degrees F., and the frost-free period is 50 to 80 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ginserly, Tristan, Anatone, Lickskillet and Tuscor soils. Anatone soils are loamy-skeletal and shallow to bedrock and are on adjacent ridgetops. Ginserly soils are loamy-skeletal and are deep to bedrock. Tristan soils are loamy-skeletal, deep to bedrock, and are on adjacent south slopes at lower elevations. Tuscor soils are clayey-skeletal, deep to bedrock, and are on adjacent south slopes. Lickskillet soils are loamy-skeletal, shallow to bedrock and are on adjacent south slopes and ridgetops at lower elevations.

DRAINAGE AND PERMEABILITY: Well drained, permeability is moderate.

USE AND VEGETATION: Hatrock soils are used mainly for livestock grazing and wildlife habitat. The native vegetation is Idaho fescue, bluebunch wheatgrass, and mountain big sagebrush and antelope bitterbrush.

DISTRIBUTION AND EXTENT: Central Oregon; MLRA 10, john Day area. This series is not extensive.

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

SERIES PROPOSED: Crook County Area, Oregon; 1999.

REMARKS: Diagnostic horizons and features include:

Mollic epipedon - from the surface to a depth of 12 inches (A1 and A2 horizons)

Cambic horizon - the zone from 12 to 23 inches (A2 horizon)

Vitrandic feature - from the surface to a depth of 60 inches

Ashy-skeletal - the PSCS averages about 40 percent rock fragments and 40 percent glass.


National Cooperative Soil Survey
U.S.A.