LOCATION MARTILLO TX

Established Series
Rev. JLR/ACT
10/2012

MARTILLO SERIES

The Martillo series consists of very deep, well drained, slowly permeable soils. These nearly level to very gently sloping soils formed in clayey alluvium. They are on broad upland alluvial flats and fan skirts. Slopes range from 0 to 3 percent.

TAXONOMIC CLASS: Fine, mixed, superactive, thermic Sodic Ustic Haplocambids

TYPICAL PEDON: Martillo clay loam - rangeland. (Colors are for dry soil unless otherwise stated.)

A--0 to 4 inches; light brown (7.5YR 6/3) clay loam, brown (7.5YR 4/3) moist; weak; abrupt medium granular structure; friable, hard, moderately sticky, moderately plastic; many fine and many medium roots; 2 percent tuff gravel; slight effervescence; moderately alkaline smooth boundary (2 to 6 inches thick)

Bn1--4 to 12 inches; brown (7.5YR 5/3) clay, dark brown (7.5YR 3/3) moist; moderate coarse prismatic structure parting to moderate medium subangular blocky; firm, very hard, very sticky, very plastic; many fine and many medium roots; 2 percent tuff gravel; strong effervescence; moderately alkaline; abrupt wavy boundary (4 to 18 inches thick)

Bn2--12 to 17 inches; brown (7.5YR 5/4) clay, dark brown (7.5YR 3/3) moist; weak medium subangular blocky structure; firm, very hard, very sticky, very plastic; common fine and common medium roots; 5 percent tuff gravel; strong effervescence; moderately alkaline; clear wavy boundary (4 to 20 inches thick)

Bn3--17 to 23 inches; light brown (7.5YR 6/4) clay, brown (7.5YR 5/4) moist; moderate fine and medium subangular blocky structure; firm, very hard, very sticky, very plastic; common fine tubular pores; 10 percent tuff gravel; strong effervescence; moderately alkaline; clear wavy boundary (6 to 17 inches thick)

2Bnz--23 to 34 inches; brown (7.5YR 5/4) loam, dark brown (7.5YR 3/4) moist; weak fine and medium subangular blocky structure; firm, very hard, moderately sticky, moderately plastic; common very fine tubular pores; 5 percent carbonate masses; 10 percent tuff gravel; strong effervescence; moderately alkaline; gradual wavy boundary (8 to 15 inches thick)

2Bknz1--34 to 44 inches; brown (7.5YR 5/4) loam, brown (7.5YR 4/4) moist; weak fine and medium subangular blocky structure; firm, very hard, moderately sticky, moderately plastic; common very fine tubular pores; 5 percent carbonate masses; 12 percent tuff gravel; violent effervescence; moderately alkaline; gradual wavy boundary (7 to 14 inches thick)

2Bknz2--44 to 55 inches; brown (7.5YR 5/4) loam, brown (7.5YR 4/4) moist; weak fine and medium subangular blocky structure; firm, very hard, moderately sticky, moderately plastic; common very fine tubular pores; 5 percent carbonate masses; 10 percent tuff gravel; strong effervescence; moderately alkaline; gradual wavy boundary (7 to 16 inches thick)

2B'n1--55 to 64 inches; brown (7.5YR 5/4) loam, brown (7.5YR 4/4) moist; weak fine and medium subangular blocky structure; firm, very hard, moderately sticky, moderately plastic; common very fine tubular pores; 2 percent carbonate masses; 1 percent tuff cobbles and 5 percent tuff gravel; strong effervescence; moderately alkaline; gradual wavy boundary (8 to 40 inches thick)

3B'n2--64 to 72 inches; reddish brown (2.5YR 5/4) clay loam, reddish brown (2.5YR 4/4) moist; weak fine subangular blocky structure; firm, very hard, moderately sticky, moderately plastic; 5 percent carbonate masses; a pebble band composed of coarse subrounded igneous gravel occurs at base of horizon; strong effervescence; moderately alkaline; clear wavy boundary (6 to 20 inches thick)

3CBkn--72 to 80 inches; light reddish brown (5YR 6/4) silty clay loam, reddish brown (5YR 5/4) moist; weak fine subangular blocky structure; firm, very hard, moderately sticky, moderately plastic; many fine roots and many medium roots; 8 percent carbonate masses; strong effervescence; moderately alkaline.

TYPE LOCATION: Presidio County, Texas; from the junction of U.S. Highways 90 and 67 in Marfa; 7.2 miles south on U.S. Highway 67 to Texas ranch road 169; 25 miles south east on Texas ranch road 169 to end of pavement; 3.2 miles south on county road; 7.6 miles east and south on county road; 1.1 miles east on ranch road to junction; 1.1 miles southeast on ranch road to junction; 1.7 miles east on ranch road to junction; 0.6 mile southeast on ranch road; 2,000 feet west in rangeland; McKinney Mountain, Texas USGS topographic quadrangle; Latitude: 29 degrees, 48 minutes, 4.865 seconds North Longitude: 103 degrees, 49 minutes, 3.558 seconds West; NAD 83; UTM Easting: 614265 m, UTM Northing: 3297360 m, Zone 13.

RANGE IN CHARACTERISTICS:

Soil moisture: Ustic aridic soil moisture regime

Solum thickness: 60 to 80 inches. Some pedons have soft volcanic tuff bedrock below a depth of 60 inches

Calcium carbonate equivalent: less than 15 percent

Clay content: 35 to 55 percent

Rock fragments: 0 to 15 percent

Linear extensibility: less than 6.0 cm to a depth of 100 cm ; slickensides are not present

Sodium adsorption ratio: 15 to 50 percent in the upper part; 25 to 65 percent in the lower part

Reaction: moderately alkaline or strongly alkaline

A horizon
Hue: 7.5YR, 10YR
Value: 4 through 6, dry or moist
Chroma: 2 through 4, dry or moist
Texture: loam, clay loam

Bn horizons
Hue: 5YR, 7.5YR
Value: 3 through 6, dry or moist
Chroma: 2 through 4, dry or moist
Texture: clay

2Bn and 3Bn horizons
Hue: 2.5YR, 5YR, 7.5YR
Value: 5 through 7, dry or moist
Chroma: 3 through 4, dry or moist
Texture: loam, sandy clay loam, clay loam, silty clay loam
Salinity: 4 to 16 dS/m
Rock fragments: 0 to 15 percent

CB or BC horizons
Similar to 2Bn or 3Bn horizons

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Martillo soils are on broad alluvial flats and fan skirts in a mountain and bolson landscape. Slopes are dominantly less than 1 percent, but range up to 3 percent. The soils formed in clayey alluvium predominantly from tuffaceous materials. Mean annual precipitation ranges from 10 to 15 inches, and mean annual air temperature ranges from 62 to 68 degrees F. Frost-free period ranges from 210 to 260 days, and elevation ranges from 3,500 to 5,000 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kinco, Potrillo, and Stovall series. Kinco soils have less than 18 percent clay in the control section and are on gently sloping upland plains. Potrillo soils have less than 20 percent clay in the control section and are on undulating ridges and fans. Stovall soils have between 18 and 35 percent clay in the control section and are on nearly level to gently sloping upland plains, valleys and alluvial fans.

DRAINAGE AND PERMEABILITY: Well drained. Permeability is slow. Runoff is medium on slopes less than 1 percent, and high on 1 to 3 percent slopes. Overland flow may occur once in 7 to 20 years for a duration of less than 2 days. When overland flow occurs it is usually in the months of July through September.

USE AND VEGETATION: This soil is used for livestock grazing and wildlife habitat. Native vegetation is mainly drought tolerant short to mid grasses such as tobosa, vine mesquite, blue grama, cane bluestem, sideoats grama, alkali sacaton, and sand muhly. Woody species consist mainly of mesquite.

DISTRIBUTION AND EXTENT: West Texas. MLRA 42. The series is of minor extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Brewster County, Texas, 1996. The name is from Rancho del Martillo ranch

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - the zone from 0 to 3 inches (A horizon)

Cambic horizon - the zone from 3 to 16 inches (Bn1 and Bn2 horizons)

Sodic feature - sodium adsorption ration of greater than 15 that is greater than 10 inches thick within 40 inches of the surface.

Ustic feature - the soils are in the aridic moisture regime that borders on the ustic moisture regime.

Classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Eleventh Edition, 2010

Update and revisions for Recorrelation Brewster County, Texas, Main Part, 2/12/08, CEM

Revised for the correlation of Presidio County, Texas ; Oct, 2012, WWJ

ADDITIONAL DATA: Classification change from Ustic Haplocambids to Sodic Ustic Haplocambids based on TAMU laboratory data (S93TX-043-004). These soils were previously included in the Verhalen series.

National Cooperative Soil Survey
U.S.A.