LOCATION SHERM TX+NM OKEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Torrertic Paleustolls
TYPICAL PEDON: Sherm silty clay loam, on a nearly level plain, 0.5 percent slopes in cultivated field. (Colors are for dry soil unless otherwise stated.)
Ap--0 to 21 cm (0 to 8 in); brown (7.5YR 4/2) silty clay loam, dark brown (7.5YR 3/2) moist; weak medium subangular blocky structure; slightly hard, friable; when dry cracks 13 mm wide at the surface extend through the horizon; neutral; clear smooth boundary. (13 to 25 cm [5 to 10 inches] thick)
Bt1--21 to 46 cm (8 to 18 in); brown (7.5YR 4/3) silty clay, dark brown (7.5YR 3/3) moist; moderate coarse prismatic structure parting to strong medium angular blocky; few peds tilted 5 to 10 degrees from horizontal; very hard, very firm; common very fine pores; when dry cracks 13 mm wide extend through the horizon; common distinct clay films and common pressure faces on ped faces; slightly alkaline; clear smooth boundary.
Bt2--46 to 73 cm (18 to 28 in); brown (7.5YR 4/4) clay, dark brown (7.5YR 3/4) moist; moderate coarse prismatic structure parting to strong medium angular blocky; few peds tilted 5 to 10 degrees from horizontal; very hard, very firm; common very fine pores; when dry cracks 6 mm wide extend through the horizon; common distinct clay films and common pressure faces on ped faces; slightly effervescent; moderately alkaline; clear smooth boundary. (combined thickness of the Bt horizons is 45 to 125 cm [18 to 50 inches])
Btk1--73 to 125 cm (28 to 49 in); reddish yellow (5YR 6/6) silty clay, yellowish red (5YR 5/6) moist; moderate coarse prismatic structure parting to moderate medium angular blocky; very hard, very firm; common very fine pores; common distinct clay films on ped faces; estimated 5 percent by volume of calcium carbonate in the form of masses; strongly effervescent; moderately alkaline; abrupt smooth boundary. (25 to 60 cm [10 to 24 inches] thick)
Btkk--125 to 154 cm (49 to 60 in); pink (5YR 8/4) clay, pink (5YR 7/4) moist; weak medium subangular blocky structure; slightly hard, friable; few faint clay films on ped faces; estimated 60 percent by volume of calcium carbonate in the form of masses, nodules, and finely disseminated carbonates; violently effervescent; strongly alkaline; gradual wavy boundary. (13 to 60 cm [6 to 24 inches] thick)
Btk2--154 to 203 cm (60 to 80 in); reddish yellow (5YR 6/6) clay, yellowish red (5YR 5/6) moist; weak medium subangular blocky structure; slightly hard, friable; few very fine pores; few distinct clay films on ped faces; estimated 35 percent by volume of calcium carbonate in the form of masses, nodules, and finely disseminated carbonates; violently effervescent; moderately alkaline.
TYPE LOCATION: Sherman County, Texas; From the intersection of Highway 119 and Highway 15 approximately 23 kilometers (14 miles) east of Stratford; 10 kilometers (6.2 miles) east on Highway 15; 1.1 kilometers (0.7 miles) north on farm road; 53 meters (173 feet) east in cultivated field; Latitude: 36 degrees 20 minutes 16.8 seconds N; Longitude; 101 degrees 42 minutes 50.6 seconds W; Coldwater Creek, Texas USGS quad; NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture: An ustic moisture regime bordering on aridic. The soil moisture control section is dry in some or all parts for more than 180 but less than 205 days, cumulative, in normal years. July through August and December through February are the driest months. These soils are intermittently moist in September through November and March through June.
Mean annual soil temperature: 13 to 15 degrees C (55 to 59 degrees F).
Depth to secondary calcium carbonate: 64 to 115 cm (25 to 45 inches).
Depth to calcic horizon: 100 to 150 cm (40 to 60 inches).
Thickness of the mollic epipedon: 25 to 50 cm (10 to 20 inches).
Solum thickness: more than 203 cm (80 inches).
Particle-size control section: 38 to 48 percent silicate clay.
Linear extensibility: averages 7 to 9 cm to a depth of 100 cm. When dry surface cracks extend through the horizons to depths exceeding 50 cm.
Ap horizon:
Hue: 7.5YR or 10YR
Value: 3 to 5, 2 or 3 moist
Chroma: 2 or 3
Texture: clay loam, silty clay loam
Effervescence: none
Reaction: neutral to slightly alkaline
Upper Bt horizons:
Hue: 7.5YR or 10YR
Value: 3 to 5, 2 to 4 moist
Chroma: 2 or 3
Texture: clay loam, silty clay loam, silty clay
Effervescence: none
Reaction: slightly alkaline or moderately alkaline
Lower Bt horizons:
Hue: 5YR to 7.5YR
Value: 4 to 6, 3 to 5 moist
Chroma: 4 to 6
Texture: clay loam, silty clay loam, silty clay
Visible secondary calcium carbonate: less than 2 percent as films or filaments.
Effervescence: none to slight
Reaction: moderately alkaline
Btk horizons:
Hue: 5YR or 7.5YR
Value: 5 to 7, 4 to 6 moist
Chroma: 3 to 6
Texture: clay loam, silty clay loam, silty clay, clay
Visible secondary calcium carbonate: 3 to 49 percent by volume as films, filaments, masses, and nodules.
Effervescence: slight to violent
Reaction: moderately alkaline or strongly alkaline
Btkk horizons:
Hue: 5YR or 7.5YR
Value: 7 or 8
Chroma: 1 to 6
Texture: clay loam, silty clay, clay
Visible secondary calcium carbonate: 50 to 80 percent by volume as films, filaments, masses, and nodules.
Effervescence: violent
Reaction: moderately or strongly alkaline
2Btk horizons (where present):
Hue: 5YR to 7.5YR
Value: 5 to 7, 4 to 6 moist
Chroma: 3 to 6
Texture: clay loam, silty clay loam, clay
Visible calcium carbonate: less than 2 to 30 percent by volume as films, filaments, masses, and nodules.
Effervescence: slight to violent
Reaction: moderately alkaline
COMPETING SERIES:
There are no other series in this family. Similar soils include the
Perryton,
Dumas,
Gruver,
Pullman,
Texline,
Richfield, and
Zella series.
Perryton series: have a silicate clay decrease of 20 percent from the maximum within 150 cm or chroma less than 5; in addition depth to the calcic horizon ranges from 150 to 203 cm.
Dumas and Texline series: have 18 to 35 percent silicate clay in the particle-size control section.
Gruver series: have a linear extensibility that averages less than 6 cm to a depth of 100 cm.
Pullman series: have average annual soil temperatures of more than 15 degrees C.
Richfield and Zella series: have a silicate clay decrease of 20 percent from the maximum within 150 cm and chroma less than 5; in addition these soils do not have a calcic horizon.
GEOGRAPHIC SETTING:
Parent material: Loamy and clayey eolian sediments of Pleistocene age.
Landform: eolian plain
Slopes: Range from 0 to 3 percent
Mean annual air temperature: 12 to 14 degrees C (53 to 57 degrees F)
Mean annual precipitation: 432 to 559 mm (17 to 22 inches)
Frost-free period: 170 to 200 days
Elevation: 916 to 1,448 meters (3,000 to 4,750 feet)
Thornthwaite annual P-E Index Values: 25 to 36
GEOGRAPHICALLY ASSOCIATED SOILS:
These are the similar
Perryton,
Dumas,
Gruver, and
Texline soils and the
Conlen,
Dalhart,
Hansford,
Knoblaw,
Lautz,
Oslo,
Plack, and
Sunray soils.
Dumas, Gruver, Perryton, and Texline soils: are on similar landscape positions.
Conlen soils: are on plains or valley sides of plains and have carbonatic mineralogy.
Dalhart soils: are on similar landscape positions and have an ochric epipedon.
Hansford, Knoblaw, and Lautz soils: are on the floor of playa basins.
Oslo soils: are on similar landscape positions and have 18 to 35 percent silicate clay in the particle-size control section.
Plack soils: are on landscape positions adjacent to draws and have a petrocalcic horizon.
Sunray soils: are on similar landscape positions or a side slope on a draw and have 18 to 35 percent silicate clay in the particle-size control section.
DRAINAGE AND PERMEABILITY: Well drained. Slow permeability. Surface runoff is medium on 0 to 1 percent slopes and high on 1 to 3 percent slopes.
USE AND VEGETATION: Principal crops grown are corn, grain sorghum, and winter wheat. A considerable amount of acreage is irrigated. Climax vegetation in rangeland includes blue grama and buffalograss, with lesser amounts of vine-mesquite, western wheatgrass, galleta or tobosa, silver bluestem, wild alfalfa, and prairieclover. This soil has been correlated to the Deep Hardland (077AY001TX) ecological site in MLRA-77A.
DISTRIBUTION AND EXTENT: Southern High Plains, Northern Part of Texas, eastern New Mexico, and the panhandle of Oklahoma (MLRA-77A in LRR H). The series is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Temple, Texas
SERIES ESTABLISHED: Sherman County, Texas; 1970.
REMARKS: The Sherm Series is a Benchmark soil.
This series revised during the MLRA-77 Update Soil Survey of Hansford County, Texas; 2007. Sherm soils were formerly included in the Pullman or Richfield series.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 0 to 46 cm (Ap and Bt1 horizons)
Argillic horizon: 21 to 203 cm (Bt, Btk, Btkk horizons)
Calcic horizon: 125 to 203 cm (Btkk and Btk2 horizons)
Carbonate plugged horizon: 125 to 154 cm (Btkk horizon)
Torrertic properties: Wedge-shaped aggregates in a layer 15 cm or more thick and cracks 5 mm or more wide through a thickness of 30 cm or more and have linear extensibility that is 6.0 cm or more to a depth of 100 cm.
ADDITIONAL DATA: Texas Tech University lab data pedon ID number: S05TX-421-001, S05TX-421-001 (Sherman County, Texas); NSSL data available on mechanical analysis and mineralogy: S84TX341-001, S94TX341-001 (Moore County, Texas); S57TX195-001, S94TX195-002, S94TX195-003 (Hansford County, Texas); S94TX233-003 (Hutchinson County, Texas); S94TX357-003 (Ochiltree County, Texas).
TAXONOMIC VERSION: Keys to Soil Taxonomy, 10th Edition, 2006.