LOCATION DONTWANNA          CA
Established Series
Rev. AMB-EWB-TM-JBF
03/2010

DONTWANNA SERIES

The Dontwanna series consists of moderately deep to a duripan, well drained soils that formed in predominantly volcanic alluvium derived from volcanic rock such as andesite. Dontwanna soils are on glacial outwash fan remnants. Slopes are 8 to 30 percent. The mean annual precipitation is about 380 mm and the mean annual temperature is about 8 degrees C.

TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Haplic Palexerollic Durixerolls

TYPICAL PEDON: Dontwanna extremely cobbly loam --rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 35 percent gravel, 25 percent cobbles, 10 percent stones and 5 percent boulders.

A--0 to 8 cm grayish brown (10YR 5/2) extremely cobbly loam, very dark grayish brown (10YR 3/2) moist; moderate thick platy structure parting to moderate medium platy structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine interstitial and common very fine vesicular pores; 25 percent subangular gravel, 25 percent subangular cobbles and 10 percent subangular stones; neutral (pH 6.9); clear smooth boundary (5 to 15 cm thick).

Bt1--8 to 23 cm; brown (7.5YR 5/3) very cobbly clay loam, dark brown (7.5YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, moderately sticky and moderately plastic; common fine and medium roots and many very fine roots; common very fine tubular and many very fine interstitial pores; 25 percent faint clay bridges between sand grains; 20 percent subangular gravel, 15 percent subangular cobbles and 5 percent subangular stones; neutral (pH 6.9); clear wavy boundary (8 to 15 cm thick).

Bt2--23 to 36 cm; brown (7.5YR 5/3) very cobbly clay, dark brown (7.5YR 3/3), moist; strong fine and medium angular blocky structure; very hard, very firm, very sticky and moderately plastic; few fine and medium roots and common very fine roots; common very fine interstitial and common very fine tubular pores; 25 percent distinct pressure faces on bottom faces of peds and 50 percent prominent clay films on surfaces along pores and 50 percent prominent clay films on all faces of peds; 35 percent subangular gravel, 15 percent subangular cobbles and 5 percent subangular stones; neutral (pH 6.9); clear wavy boundary (10 to 25 cm thick).

Bt3--36 to 51 cm; light brown (7.5YR 6/4) very cobbly clay, brown (7.5YR 4/4), moist; strong fine and medium angular blocky structure; very hard, very firm, very sticky and very plastic; few very fine to medium roots; common very fine interstitial and common very fine tubular pores; 5 percent distinct pressure faces on bottom faces of peds and 50 percent prominent clay films on all faces of peds and 50 percent prominent clay films on surfaces along pores; 10 percent subangular paragravel, 30 percent subangular gravel, 15 percent subangular cobbles and 10 percent subangular stones; neutral (pH 7.3); clear wavy boundary (14 to 20 cm thick).

Bt4--51 to 66 cm; light brown (7.5YR 6/4) very cobbly clay, brown (7.5YR 4/4), moist; strong fine and medium angular blocky structure; very hard, very firm, very sticky and very plastic; few very fine roots; common very fine interstitial and common very fine tubular pores; 5 percent distinct pressure faces on bottom faces of peds and 50 percent prominent clay films on all faces of peds and 50 percent prominent clay films on surfaces along pores; 10 percent subangular paragravel, 5 percent subangular paracobbles, 25 percent subangular gravel, 15 percent subangular cobbles and 5 percent subangular stones; slightly alkaline (pH 7.4); clear wavy boundary (14 to 30 cm thick).

Bkqm--66 to 152 cm; moderately silica cemented material; massive; very firm; 10 percent subangular paragravel, 5 percent subangular paracobbles, 25 percent subangular gravel, 15 percent subangular cobbles and 5 percent subangular stones; slight effervescence.

TYPE LOCATION: Mono County, California; in Slinkard Valley about 3.55 kilometers northwest of the Junction of CA state route 89 and US highway 395; Topaz Lake USGS 7.5 minute topographic quadrangle; latitude 38 degrees 39 minutes 03.0 seconds N and longitude 119 degrees 34 minutes 01.8 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in the moisture control section; moist winter and spring; usually dry July through early October; xeric moisture regime, bordering on aridic.
Mean annual soil temperature: 7 to 8 degrees C.
Mollic epipedon thickness: 25 to 50 cm.
Depth to duripan: 50 to 100 cm
Depth to bedrock: More than 150 cm.

Particle-size control section - Clay content: Averages 35 to 50 percent.
Rock fragments: Averages 50 to 80 percent, mainly cobbles. Lithology of rock fragments is volcanic rock such as andesite.

A horizon
Chroma: 2 or 3 dry or moist.
Organic matter content: 1 to 3 percent
Reaction: Neutral or slightly acid

Bt1 and Bt2 horizons
Hue: 10YR or 7.5YR
Value: 4 or 5 dry, 3 moist
Chroma: 2 or 3 dry or moist
Texture: Very cobbly clay loam, very cobbly clay, extremely cobbly clay loam or extremely cobbly clay.
Clay content: 35 to 50 percent
Rock fragments: 50 to 80 percent
Organic matter content: 1 to 2 percent
Reaction: Neutral or slightly alkaline

Bt3 and Bt4 horizons
Hue: 10YR or 7.5YR
Value: 5 or 6 dry, 4 moist
Chroma: 3 or 4 dry or moist
Texture: Very cobbly clay loam, very cobbly clay, extremely cobbly clay loam or extremely cobbly clay.
Rock fragments: 50 to 80 percent
Organic matter content: 1 to 2 percent
Reaction: Neutral or slightly alkaline

Bqkm horizon
Cementation: Strongly or moderately silica cemented matrix
Rock fragments: 35 to 60 percent
Identifiable secondary carbonates: 0 to 5 percent filaments or coats on rock fragments

COMPETING SERIES: There are currently no other series in this family.

GEOGRAPHIC SETTING: Dontwanna soils are on glacial outwash fan remnants. They typically occur on summit positions. They formed in predominately volcanic alluvium derived from andesite. Slopes are 8 to 30 percent. Elevations range from 1,680 to 2,134 meters. The climate is semi-arid with cool, moist winters and warm, dry summers. The mean annual precipitation is 350 to 400 mm, mean annual temperature is 6 to 10 degrees C., and the frost-free period is 70 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Crispy, Heenlake, Slinkard and Toejom soils. All of these soils lack a duripan and have less than 35 percent clay in their particle size control section. In addition Crispy soils are shallow with a paralithic contact within 50 cm. Heenlake soils have a paralithic contact between 50 to 100 cm. Slinkard soils have a mollic epipedon more than 50 cm thick. Toejom soils have a paralithic contact within 50 cm and an ochric epipedon.

DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; slow permeability; low saturated hyraulic conductivity.

USE AND VEGETATION: Dontwanna soils are used for livestock grazing and wildlife habitat. The native vegetation is mainly mountain big sage brush, antelope bitterbrush, western and Thurber's neddlegrass, bottlebrush squirreltail and Sandberg bluegrass.

DISTRIBUTION AND EXTENT: Eastern California, east of the Sierra Nevada Range. These soils are not extensive. MLRA 22.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: Mono County (Coleville-Bridgeport Area), California, 2010.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 36 cm (A, Bt1 and Bt2 horizons).
Argillic horizon - The zone from 8 to 66 cm (Bt1, Bt2 and Bt3 horizons).
Identifiable secondary carbonates - The zone from 66 to 152 cm (Bqkm horizon).
Strongly cemented duripan - The zone from 66 to 152 cm (Bqkm horizon).
Particle-size control section - The zone from 8 to 58 cm (Bt1, Bt2, Bt3 and upper Bt4 horizons).


National Cooperative Soil Survey
U.S.A.