LOCATION TUWEEP AZ
Established Series
Rev. RJA/DRT/RLB
10/2011
TUWEEP SERIES
The Tuweep series consists of deep, well drained soils that formed in alluvium from pyroclastics and basalt. Tuweep soils are on plateaus and mesas and have slopes of 0 to 15 percent. The average annual precipitation is about 11 inches and the mean annual temperature is about 54 degrees F.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Ustic Calciargids
TYPICAL PEDON: Tuweep very gravelly loam, rangeland. (Colors are for dry soil unless otherwise noted.) Surface is covered by 70 percent pebbles and 10 percent cobbles.
A--0 to 3 inches; pale brown (10YR 6/3) very gravelly loam, brown (10YR 4/3) moist; moderate thick platy structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine and medium roots; many very fine and fine vesicular pores; 55 percent pebbles; slightly effervescent; slightly alkaline (pH 7.5); clear smooth boundary. (2 to 4 inches thick)
Bt--3 to 9 inches; pale brown (10YR 6/3) clay loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; common fine and medium roots; common fine tubular and interstitial pores; few thin clay films in pores; 10 percent pebbles; slightly effervescent; slightly alkaline (pH 7.7); clear wavy boundary. (4 to 8 inches thick)
Btk--9 to 16 inches; light yellowish brown (10YR 6/4) clay loam, brown (7.5YR 5/4) moist; moderate very fine and fine subangular blocky structure; slightly hard, very friable, sticky and slightly plastic; common fine and medium roots; common fine tubular and interstitial pores; few moderately thick clay films in tubular pores; strongly effervescent; moderately alkaline (pH 8.1); clear wavy boundary. (5 to 8 inches thick)
Bk1--16 to 34 inches; very pale brown (10YR 8/3) clay loam, light brown (7.5YR 6/4) moist; massive; slightly hard, very friable, slightly sticky and nonplastic; few fine and medium roots; few fine interstitial pores; 70 percent lime coated basalt stones; violently effervescent; moderately alkaline (pH 8.2); abrupt irregular boundary. (18 to 30 inches thick)
2Bk2--34 to 60 inches; light yellowish brown (10YR 6/4) very stony loam, brown (7.5YR 5/4) moist; massive; soft, very friable, sticky and plastic; common fine and medium roots; few very fine and fine tubular pores; (45 percent calcium carbonate equivalent); common soft lime mass; violently effervescent; moderately alkaline (pH 8.2); abrupt irregular boundary. (18 to 30 inches thick)
TYPE LOCATION: Coconino County, Arizona, about 25 miles northeast of the City of Flagstaff; 2,500 feet west and 2,000 feet south of the NE corner of sec. 3, T.26N., R.8E.
RANGE IN CHARACTERISTICS:
Soil moisture: Intermittently moist in the SMCS in some parts of July-September and December-February. Ustic aridic moisture regime.
Depth to calcic horizon: 10 to 20 inches
Rock fragments: Less than 35 percent gravel and cobbles in the control section
A horizon
Hue: 10YR, 7.5YR
Value: 5 or 6 dry, 3 or 4 moist
Chroma: 3 dry, 2 or 3 moist
Texture: loam (18 to 25 percent clay)
Reaction: slightly or moderately alkaline
Bt horizon
Hue: 10YR, 7.5YR
Value: 5 to 7 dry, 3 to 5 moist
Chroma: 3 or 4 dry or moist
Texture: loam, silty clay loam, clay loam (28 to 34 percent clay)
Carbonates: greater than 15 percent
Reaction: slightly or moderately alkaline
Sand: less than 35 percent fine and coarser sand
Bk horizon:
Hue: 10YR, 7.5YR
Value: 6 to 8 dry, 4 to 6 moist
Chroma: 2 to 4 dry, 4 moist
Texture: clay loam, loam (15 to 34 percent clay)
Carbonates: greater than 15 percent calcium carbonate, segregated soft lime masses and coatings on rock fragments
Reaction: slightly alkaline or moderately alkaline
COMPETING SERIES: These are the
Alvey (UT),
Barx (UT),
Cabreros (NM),
Cerrillos (NM),
Clovis (NM),
Fernando (NM),
Flaco (NM),
Horchata (NM),
Maysdorf (WY),
Millett (AZ),
Palabria (NM),
Progresso (CO),
Sanostee (NM),
Scholle (NM),
Selpats (WY),
Solirec (UT),
Spenlo (UT),
Threetop (WY), and
Wineg (AZ) series. Alvey soils have hue of 10YR or yellower. Barx soils contain 2.5YR and 5YR hue. Cerrillos soils have a calcic horizon less than 20 inches deep. Clovis soils receive more than half of it annual precipitation between the months of July and October. Fernando soils contain 50 to 80 percent silt in the solum and are mapped in MLRA 51. Cabreros, Flaco, Horchata, Progresso, Sanostee, and Threetop soils are moderately deep over bedrock. Maysdorf soils contain less than 15 percent carbonates in the calcic horizon. Millett soils contain 25 to 75 percent gravel and cobbles in the lower part of the solum. Palabria soils are deep to sandstone. Selpats soils have skeletal lithologic discontinuity at depths ranging from 15 to 39 inches. Scholle soils contain 15 to 35 percent gravel in the control section. Solirec soils receive maximum precipitation in spring and fall. Wineg soils have a MAST of 56 degrees F, and have mixed gravelly alluvium or lacustrine parent material. Cerrillos, Clovis, Millett and Scholle soils have hue of 7.5YR or redder in the B2t horizon. Fernando soils are deeper than 20 inches to the calcic horizon. Spenlo soils have a solum more than 40 inches thick and are noncalcareous to a depth of 35 to 44 inches.
GEOGRAPHIC SETTING: The Tuweep soils are on plateaus and mesas with gradients of 0 to 15 percent. Elevations range from 4,800 to 6,400 feet. They formed in basalt and pyroclastics including cinders, tuff and volcanic breccia. The climate is semiarid with average annual precipitation is 8 to 14 inches occurring as summer thunderstorms and as winter rain and snow. The average annual air temperature is 54 degrees F. Frost-free season is about 120 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Apache,
Aut,
Cross,
Epikom,
Lomaki,
Nalaki,
Winona,
Wukoki, and Wupaki soils. Apache, Cross, Epikom and Winona soils are shallow over bedrock. Aut soils are moderately deep over bedrock. Lomaki and Wukoki soils have a mollic epipedon. Nalaki and Wupaki soils have a duripan.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately slow permeability.
USE AND VEGETATION: Used mainly for grazing and wildlife habitat. Native vegetation is mainly alkali sacaton, galleta, black grama, bush muhly, and sideoats grama.
DISTRIBUTION AND EXTENT: Northern Arizona. The series is moderately extensive. MLRA 35.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.
SERIES ESTABLISHED: Coconino County Area, Arizona, Central Part; March 1980.
REMARKS: Diagnostic horizon and features recognized in this pedon are:
Ochric epipedon- the zone from 0 to 3 inches (A horizon)
Argillic horizon -the zone from 3 to 16 inches (Bt and Btk horizon)
Calcic horizon - the zone from 16 to 60 inches (Bk1 and 2Bk2 horizon)
Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy Eleventh Edition, 2010
Update and revisions for the correlation of Little Colorado River Area (AZ707), Sept. 2011, CEM
Pronounced Two-weep
ADDITIONAL DATA: NSSL Sample S75 AZ-05-1.
National Cooperative Soil Survey
U.S.A.