LOCATION ARCH               NM+TX

ARCH SERIES

TAXONOMIC CLASS: Fine-loamy, carbonatic, thermic Aridic Calciustepts

TYPICAL PEDON: Arch fine sandy loam, on a west-facing, concave, about 1 percent slope in rangeland at an elevation of about 1,268 meters (4,160 feet). (Colors are for dry soil unless otherwise stated)

A--0 to 15 cm (0 to 6 inches); brown (10YR 5/3) fine sandy loam, brown (10YR 4/3) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine roots; few medium pores; disseminated calcium carbonate; violently effervescent; moderately alkaline; clear smooth boundary. (8 to 25 cm thick).

Bk1--15 to 41 cm (6 to 16 inches); pale brown (10YR 6/3) sandy clay loam, brown (10YR 5/3) moist; weak fine and medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine roots; few medium pores; common fine masses and disseminated calcium carbonate; violently effervescent; moderately alkaline; clear smooth boundary.

Bk2--41 to 94 cm (16 to 37 inches); very pale brown (10YR 8/3) sandy clay loam, very pale brown (10YR 7/3) moist; weak medium subangular blocky structure; slightly hard, friable, sticky and plastic; common very fine roots; few medium pores; many fine and medium masses and disseminated calcium carbonate; violently effervescent; moderately alkaline; gradual smooth boundary.

Bk3--94 to 203 cm (37 to 80 inches); very pale brown (10YR 7/3) sandy clay loam, pale brown (10YR 6/3) moist; weak medium subangular blocky structure; slightly hard, friable, sticky and plastic; few fine roots; many large masses and disseminated calcium carbonate; violently effervescent; strongly alkaline. (combined thickness of Bk horizons is 25 to 203 cm)

TYPE LOCATION: Curry County, New Mexico; from the intersection of U.S. Highways 60 and 84 and New Mexico Highway 88 in Melrose, about 9.7 kilometers (6 miles) south on New Mexico Highway 88, west on Boy's Ranch Road about 3.6 kilometers (2.25 miles), north on private road 1.2 kilometers (0.75 miles) on east side of road; or 259 meters (850 feet) south and 335 meters (1,100 feet) east of the NW corner sec. 35, T. 2N, R. 31E in rangeland; Latitude: 34 degrees, 21 minutes, 32 seconds N; Longitude: 103 degrees, 39 minutes, 54 seconds W; Tule Lake, New Mexico USGS quad; NAD 87.

RANGE IN CHARACTERISTICS:
Soil moisture: Ranges from an ustic moisture regime bordering on aridic to an aridic moisture regime bordering on ustic. The soil moisture control section is dry in some or all parts for more than 180 but less than 270 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: 15 to 17 degrees C (59 to 62 degrees F).
Depth to secondary calcium carbonate: 8 to 25 cm (3 to 10 inches).
Depth to calcic horizon: 25 to 51 cm (10 to 20 inches).
Solum thickness: more than 203 cm (80 inches).
Particle-size control section: 18 to 35 percent silicate clay.

A horizon:
Hue: 10YR
Value: 5 or 6, 4 or 5 moist
Chroma: 3 or 4
Texture: loamy fine sand, fine sandy loam, loam
Effervescence: violent
Reaction: slightly alkaline or moderately alkaline

Bk horizons:
Hue: 7.5YR or 10YR
Value 5 to 7, 4 to 6 moist
Chroma: 2 to 4
Texture: fine sandy loam, sandy clay loam, loam, clay loam
Silicate clay content: 18 to 35 percent
Visible calcium carbonate: 5 to 70 percent
Calcium carbonate equivalent: 40 to 60 percent
Effervescence: violent
Reaction: moderately alkaline or strongly alkaline

COMPETING SERIES: This is the Veal series. Similar soils include the Cedarlake, Drake, Hindman, Lenorah, Midessa, and Portales series.
Veal series: has colors redder than 7.5YR in the subsoil and has formed in loamy alluvial and colluvial sediments derived from the Ogallala Formation of Miocene-Pliocene age.
Cedarlake, Drake, Hindman, Midessa, and Lenorah series: do not have carbonatic mineralogy, and Hindman has less than 18 percent silicate clay in the particle-size control section.
Portales series: has a mollic epipedon and does not have carbonatic mineralogy.

GEOGRAPHIC SETTING:
Parent material: calcareous, loamy eolian sediments of Holocene age.
Landform: nearly level to very gently sloping playa terraces; interdunes within dune complexes on the eastern (leeward) side of playa basins or salinas.
Slopes: 0 to 5 percent.
Mean annual air temperature: 14 to 16 degrees C (57 to 60 degrees F).
Mean annual precipitation: 305 to 457 millimeters (12 to 18 inches).
Frost-free period: 195 to 205 days.
Elevation: 1,097 to 1,981 meters (3,600 to 6,500 feet).
Thornthwaite annual P-E Values: 24 to 32.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the similar Drake, Lenorah, Midessa, and Portales series and the Amarose, Chapel, Gomez, Grier, Lamesa, Lazbuddie, McLean, Milsand, Ranco, and Seagraves series.
Drake soils: are on curvilinear dunes on higher landscape positions.
Lenorah, Midessa, and Portales soils: are on higher landscape positions.
Amarose soils: occurs on higher landscape positions and have an argillic horizon.
Gomez and Milsand soils: occur on higher landscape positions. Gomez soils have less than 18 percent clay in the particle-size control section and Milsand soils have a sandy particle-size class.
Grier soils: occur in lower landscape positions and have aquic moisture conditions.
Chapel, Lazbuddie, McLean, and Ranco soils: occur on slightly lower landscape positions in playa basins and have vertic properties.
Lamesa and Seagraves soils: occur on slightly lower landscape positions in playa basins and have an argillic horizon.

DRAINAGE AND PERMEABILITY: Well drained. Moderate permeability. Surface runoff is none on 0 to 1 percent slopes.

USE AND VEGETATION: These soils are used primarily for livestock grazing. Where cultivated, the principal crops are cotton and grain sorghum. Native vegetation includes mid and tall grasses with a lesser short grass component and a few weedy plants. Forbs may also occur but are not abundant. Grasses include sideoats and blue gramas, buffalograss, western wheatgrass, alkali sacaton, vine-mesquite, and small amounts of switchgrass. Other species include prairieclover, sensitivebrier, wild alfalfa, daleas, fourwing saltbrush, and cholla. This soil has been correlated to the High Lime (077CY026TX) range site in MLRA-77.

DISTRIBUTION AND EXTENT: Southern High Plains, Southern Part (MLRA 77C in LRR H) of eastern New Mexico and western Texas. The series is of moderate extent.

MLRA OFFICE RESPONSIBLE: Temple, Texas

SERIES ESTABLISHED: Roosevelt County, New Mexico; 1940.

REMARKS: The type location and classification were changed to better reflect the manner in which Arch soils have been mapped in the past. The Arch series was previously classified as a fine-loamy, mixed, thermic Ustochreptic Calciorthid.
Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon: 0 to 15 cm. (A horizon)
Calcic horizon: 15 to 203 cm. (Bk1, Bk2, Bk3 horizons)

ADDITIONAL DATA: NSSL data on pedon S95TX-445-027 from Terry County TX.

TAXONOMIC VERSION: Keys to Soil Taxonomy, Tenth Edition, 2006.