LOCATION YAWHEE OR

Established Series
Rev. RPO/AON/RWL
05/2013

YAWHEE SERIES

The Yawhee series consists of very deep, somewhat excessively drained soils that formed in a mantle of volcanic ash over buried very gravelly loamy mixed material. Yawhee soils are on volcanic cones, escarpments, and cuestas and have slopes of 3 to 40 percent. The mean annual precipitation is about 22 inches and the mean annual temperature is about 43 degrees F.

TAXONOMIC CLASS: Ashy-skeletal over loamy-skeletal, glassy over isotic, frigid Alfic Udivitrands

TYPICAL PEDON: Yawhee stony ashy coarse sandy loam, woodland. (Colors are for moist soil unless otherwise noted.)

Oi--0 to 1 inch; slightly decomposed plant material consisting of a loose mat of pine and fir needles.

A1--1 to 3 inches; very dark grayish brown (10YR 3/2) stony ashy coarse sandy loam, dark grayish brown (10YR 4/2) dry; weak very fine granular structure; soft, very friable, slightly sticky and nonplastic; many roots; many fine pores; 15 percent gravel, 5 percent stones; slightly acid (pH 6.4); clear wavy boundary.

A2--3 to 14 inches; very dark grayish brown (10YR 3/2) very cobbly ashy coarse sandy loam, grayish brown (10YR 5/2) dry; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; many roots; many very fine pores; 20 percent gravel, 20 percent cobbles and stones; slightly acid (pH 6.4); clear wavy boundary. (Combined thickness of The A horizon is 10 to 19 inches)

C--14 to 29 inches; dark yellowish brown (10YR 3/4) very cobbly ashy loamy coarse sand, brown (10YR 5/3) dry; massive; soft, very friable; nonsticky and nonplastic; many roots; many very fine pores; 25 percent gravel, 25 percent cobbles and stones; slightly acid (pH 6.3); clear wavy boundary. (5 to 18 inches thick)

2Ab--29 to 38 inches; dark brown (10YR 3/3) very gravelly fine sandy loam, brown (10YR 4/3) dry; weak fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; many roots; many very fine pores; 35 percent gravel, 10 percent cobbles and stones; slightly acid (pH 6.1); clear wavy boundary. (0 to 15 inches thick)

2Btb1--38 to 51 inches; dark brown (10YR 3/3) very gravelly loam, brown (10YR 5/3) dry; common fine and medium angular blocky structure; hard, firm, slightly sticky and slightly plastic; common very fine roots; many very fine tubular pores; few faint clay films on peds; 55 percent gravel and 5 percent cobbles; slightly acid (pH 6.1); clear smooth boundary. (6 to 15 inches thick)

2Btb2--51 to 61 inches; dark brown (10YR 3/3) extremely gravelly loam, brown (10YR 5/3) dry; common fine and medium angular blocky structure; hard, firm, slightly sticky and slightly plastic; few very fine and fine roots; common very fine pores; few faint clay films on peds; 55 percent gravel, 10 percent cobbles and stones; slightly acid (pH 6.3).

TYPE LOCATION: Klamath County, Oregon, 2,545 feet west and 900 feet north of The southeast corner, sec. 19, T.36S., R.9E.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 42 to 45 degrees F. The mean summer soil temperature is 40 to 47 degrees F. Depth to bedrock is more than 60 inches. The mollic epipedon extend to depths of 10 to 19 inches thick. The ash mantle is 14 to 35 inches thick and it has 60 to 70 percent pumiceous ash and other pyroclastics. It is estimated to have a phosphate retention of 25 to 50 percent, acid oxalate extractable aluminum plus one-half iron of 0.4 to 1.0 percent, 15-bar moisture of less than 10 percent, and moist bulk density of 0.70 to 1.00 grams per cubic centimeter. Hue is 10YR to 5YR moist, and 10YR or 7.5YR dry throughout the profile. The soil is slightly acid or neutral throughout. The gravel, cobbles, and stones are hard lava fragments.

The A horizon has value of 2 or 3 moist, 3 to 5 dry, and chroma of 2 or 3 moist, 2 to 4 dry. Some of the coarse and very coarse sand grains have value of 4 moist and 6 dry, and chroma of 4 to 6 moist and 4 dry. This horizon has 10 to 30 percent gravel and 15 to 30 percent cobbles and stones.

The C horizon has value of 5 or 6 dry, and chroma of 3 or 4 moist. Coarse and very coarse sand grains have value of 4 moist and 6 dry, and chroma of 4 to 6 moist and and 4 dry. This horizon has 15 to 30 percent gravel and 20 to 35 percent cobbles and stones.

The 2Ab horizon has value of 4 or 5 dry, and chroma of 2 or 3 moist. It is loam or fine sandy loam and has 15 to 35 percent gravel and 0 to 15 percent cobbles and stones. It is absent in some pedons.

The 2Btb horizon has value of 4 or 5 dry, and chroma of 2 to 4 moist and 2 or 3 dry. It is loam or clay loam and has 20 to 30 percent clay, 45 to 55 percent gravel and 5 to 20 percent cobbles and stones.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Yawhee soils are on volcanic cones, escarpments, and backslopes of cuestas at elevations of 5,000 to 6,500 feet. The soils formed in thin mantles of slightly mixed, very cobbly dacitic ash over buried soils of mixed mineralogy. The climate is characterized by cold moist winters and cool dry summers. The mean annual precipitation is 20 to 25 inches. The mean January temperature is 25 to 27 degrees F; the mean July temperature is 57 to 62 degrees F; and the mean annual temperature is 41 to 45 degrees F. The frost-free period is 50 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are The Nuss, Ponina, Royst and Woodcock soils. These soils lack horizons having as much as 20 percent ash. Nuss soils have bedrock at depths of 12 to 20 inches and have less than 35 percent rock fragments in any part. Ponina soils have ochric epipedons, clay Bt horizons and have duripans at depths of 12 to 20 inches. Royst soils have very gravelly clay loam and gravelly clay argillic horizons and have bedrock at depths of 25 to 40 inches. Woodcock soils are medial-skeletal.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained; rapid permeability in the ashy upper horizons and moderate permeability in the loamy lower horizons.

USE AND VEGETATION: These soils are used for timber, wildlife habitat, grazing by livestock and recreation. Vegetation mainly is ponderosa pine, white fir, Douglas-fir, sugar pine, incense cedar and understory plants.

DISTRIBUTION AND EXTENT: Southern fringe of eolian pumice mantled zone south of the Sprague River in south-central Oregon; MLRA 3. The series is moderately extensive.

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

SERIES ESTABLISHED: Klamath County, Oregon, 1977.

REMARKS: Diagnostic horizons and features recognized in this pedon:

Mollic epipedon - from 1 to 14 inches (A1 and A2 horizons)

Alfic feature - a buried argillic horizon from 38 to 61 inches (2Btb1 and 2Btb2 horizons).

Andic properties - from 1 to 29 inches (A1, A2, and C horizons) based on data from the associated Steiger series.

Particle-size control section - from 1 to 41 inches with 1 to 29 inches meeting ashy-skeletal family criteria and 29 to 41 inches meeting loamy-skeletal family criteria.

Udic soil moisture regime.

National Cooperative Soil Survey
U.S.A.