LOCATION TRUEHILL NMEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Calcidic Argiustolls
TYPICAL PEDON: Truehill extremely gravelly loam, very stony--on a riser of a fan remnant sloping 28 percent to the west at 6,169 feet elevation-pinyon-juniper forestland. (Colors are for dry soil unless otherwise noted. When described August 9, 2001, the soil was dry throughout)
A--0 to 4 inches; very dark grayish brown (10YR 3/2) extremely gravelly loam, very dark brown (10YR 2/2) moist; moderate medium granular structure; slightly hard, friable, moderately sticky and moderately plastic; few medium, common fine, and common very fine roots; very few very fine tubular pores; 40 percent gravel, 15 percent cobbles, and 5 percent stones; neutral (pH 7.0); clear smooth boundary. (2 to 10 inches thick)
Bt--4 to 7 inches; very dark grayish brown (10YR 3/2) very gravelly clay loam, very dark brown (10YR 2/2) moist; strong medium granular structure; hard, firm, moderately sticky and moderately plastic; few medium, common fine, and common fine roots; very few very fine tubular pores; many distinct clay films on faces of peds; 40 percent gravel and 10 percent cobbles; neutral (pH 7.0); gradual smooth boundary. (3 to 18 inches thick)
Btk--7 to 12 inches; dark yellowish brown (10YR 4/4) very gravelly clay loam, dark brown (10YR 3/3) moist; strong medium granular structure; slightly hard, friable, moderately sticky and moderately plastic; common medium, common fine, and common very fine roots; many distinct clay films on faces of peds; 35 percent gravel and 10 percent cobbles; slightly effervescent, secondary calcium carbonates segregated as few fine irregularly shaped nodules and masses on ped faces and rock fragments; slightly alkaline (pH 7.8); clear smooth boundary. (0 to 9 inches thick)
Bk1--12 to 22 inches; light gray (10YR 7/2) extremely cobbly sandy loam, pale brown (10YR 6/3) moist; weak medium subangular blocky structure parting to single grain; slightly hard, very friable, slightly sticky and slightly plastic; few medium, few fine, and few very fine roots; 40 percent gravel and 20 percent cobbles; violently effervescent, matrix is impregnated with secondary calcium carbonate with about 25 percent occurring as strongly cemented calcium carbonate nodules; strongly alkaline (pH 8.6); diffuse irregular boundary. (7 to 23 inches thick)
Bk2--22 to 40 inches; light gray (10YR 7/2) extremely gravelly coarse sandy loam, pale brown (10YR 6/3) moist; massive parting to single grain; loose, slightly sticky and nonplastic; few medium, few fine, and few very fine roots; 50 percent gravel, 20 percent cobbles, and 5 percent stones; violently effervescent, matrix is partially impregnated with moderately cemented secondary calcium carbonate and in spots with about 25 percent occurring as strongly cemented calcium carbonate nodules; strongly alkaline (pH 8.8); gradual wavy boundary. (7 to 23 inches thick)
Bk3--40 to 49 inches; yellowish brown (10YR 5/4) extremely gravelly coarse sand, brown (10YR 4/3) moist; single grain; loose, nonsticky and nonplastic; few medium, few fine and few very fine roots; 65 percent gravel, 15 percent cobbles, and 5 percent stones; strongly effervescent, secondary calcium carbonate segregated as discontinuous coats on rock fragments and finely disseminated throughout the matrix with about 3 percent occurring as strongly cemented calcium carbonate nodules; moderately alkaline (pH 8.2); gradual wavy boundary. (9 to 33 inches thick)
Bk4--49 to 67 inches; very pale brown (10YR 8/2) extremely gravelly sandy clay loam, very pale brown (10YR 7/3) moist; massive; slightly hard, friable, moderately sticky and nonplastic; few medium, few fine, and few very fine roots; 50 percent gravel, 15 percent cobbles, and 2 percent stones; violently effervescent, matrix is impregnated with secondary calcium carbonate with about 40 percent occurring as strongly cemented calcium carbonate nodules; strongly alkaline (pH 8.8); gradual wavy boundary. (9 to 33 inches thick).
Bk5--67 to 80 inches; pale brown (10YR 6/3) extremely gravelly loamy coarse sand, dark yellowish brown (10YR 4/4) moist, single grain; loose, nonsticky and nonplastic; 40 percent gravel and 20 percent cobbles; strongly effervescent, secondary calcium carbonate segregated as discontinuous coats on rock fragments and finely disseminated throughout the matrix with about 10 percent occurring as strongly cemented calcium carbonate nodules; moderately alkaline (pH 8.4); diffuse irregular boundary. (7 to 23 inches thick)
TYPE LOCATION: Santa Fe County, New Mexico; about 3 miles south of Cerrillos, New Mexico; USGS Picture Rock 7.5 minute topographic quadrangle; Latitude 35 degrees 23 minutes 36.9 seconds North and Longitude 106 degrees 06 minutes 57.7 seconds West, NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture - The soil moisture control section is intermittently moist in some part from July to October and December to March. The soils are driest in May and June. The soil moisture regime is aridic bordering on ustic.
Average annual soil temperature - 52 to 54 degrees F
Thickness of the mollic epipedon - 2 to 10 inches
Depth to the base of the argillic horizon - 4 to 28 inches
Depth to secondary carbonates - 4 to 12 inches
Depth to horizon with partial cementation - 13 to 25 inches
Organic matter content - 2 to 4 percent in the ochric epipedon
Lithology of rock fragments: monzonite
Particle-size control section (weighted averages)
Silicate clay content: 25 to 35 percent
Sand content: 35 to 60 percent
Fine sand or coarser content: 25 to 50 percent
Rock fragment content: 35 to 60 percent
A horizon
Hue- 10YR or 7.5YR
Value- 3 through 5 dry, 2 or 3 moist
Chroma- 2 or 3, dry or moist
Clay content: 10 to 25 percent
Rock fragments: Total range is 60 to 80 percent
25 to 45 percent gravel
15 to 25 percent cobbles
0 to 10 percent stones
0 to 10 percent boulders
Bt horizon
Hue- 7.5YR through 2.5Y
Value- 3 through 6 dry, 2 through 5 moist
Chroma- 2 through 4, dry or moist
Texture: very gravelly clay loam, very cobbly clay loam, very cobbly loam, very cobbly sandy clay loam
Clay content: 21 to 37 percent
Rock fragments: Total range is 35 to 50 percent
25 to 40 percent gravel
10 to 20 percent cobbles
0 to 10 percent stones
Btk horizon (not in all pedons)
Hue- 7.5YR or 10YR
Value- 4 through 6 dry, 3 or 4 moist
Chroma- 3 or 4, dry or moist
Texture: very gravelly clay loam, very gravelly loam, very cobbly clay loam, very cobbly loam,
Clay content: 20 to 29 percent
Calcium carbonate content: 1 to 15 percent
Rock fragments: Total range is 45 to 60 percent
20 to 35 percent gravel
10 to 20 percent cobbles
0 to 10 percent stones
Upper Bk horizons
Hue- 7.5YR through 2.5Y
Value- 6 through 8 dry, 4 through 7 moist
Chroma- 1 through 4 dry, 2 through 4 moist
Texture: extremely cobbly sandy loam, extremely cobbly loam, extremely gravelly coarse sandy loam, very cobbly loam
Clay content: 7 to 26 percent
Calcium carbonate content: 20 to 40 percent
Rock fragments: Total range is 40 to 80 percent
35 to 50 percent gravel
15 to 25 percent cobbles
0 to 5 percent stones
Middle Bk horizons
Hue- 7.5YR through 2.5Y
Value- 6 through 8 dry, 4 through 7 moist
Chroma- 1 through 4 dry, 2 through 4 moist
Texture: extremely cobbly sandy loam, extremely cobbly loam, extremely gravelly coarse sandy loam, very cobbly loam
Clay content: 7 to 26 percent
Calcium carbonate content: 10 to 40 percent
Rock fragments: Total range is 40 to 85 percent
40 to 60 percent gravel
15 to 30 percent cobbles
0 to 5 percent stones
Lower Bk horizons
Hue- 7.5YR through 2.5Y
Value- 5 through 8 dry, 4 through 7 moist
Chroma- 1 through 4 dry, 2 through 4 moist
Texture: extremely gravelly coarse sand, extremely gravelly loamy coarse sand, extremely gravelly coarse sandy loam, very cobbly sandy loam, very gravelly sandy clay loam
Clay content: 7 to 29 percent
Calcium carbonate content: 1 to 20 percent
Rock fragments: Total range is 40 to 85 percent
35 to 65 percent gravel
15 to 25 percent cobbles
0 to 5 percent stones
COMPETING SERIES: These are the
Espadon,
Luckystrike,
Resolana, and
Traley series.
Espadon soils are moderately deep to bedrock.
Luckystrike soils have Bkq horizons with silica coats.
Resolana soils are in an aridic ustic moisture regime and do not have carbonate cemented nodules.
Traley soils are deep to limestone bedrock.
GEOGRAPHIC SETTING: Truehill soils are on risers of fan remnants. They formed in alluvium derived from monzonite. Slopes are 25 to 55 percent. Elevation ranges 5,400 to 7,400 feet. The mean annual precipitation is 10 to 13 inches with about 45 percent falling as rain from high-intensity convective thunderstorms between July and September. The mean annual air temperature is 50 to 52 degrees F. The frost-free period is 150 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cerrillos, Penistaja, Riovista, and Sedillo soils. Cerrillos soils are fine-loamy and occur on summits and treads of fan remnants. Penistaja soils are fine-loamy, do not have calcic horizons, and occur on toeslopes of fan remnants. Riovista soils are sandy-skeletal, do not have diagnostic subsurface horizons, and occur on valley floors. Sedillo soils occur on summits and treads of fan remnants.
DRAINAGE AND PERMEABILITY: Well drained; high surface runoff; permeability is moderately slow.
USE AND VEGETATION: Truehill soils are used for livestock grazing, wildlife habitat, and recreation. The historic climax vegetation is blue grama, black grama, New Mexico feathergrass, galleta, sideoats grama, oneseed juniper, and twoneedle pinyon. The ecological site is Gravelly(R036XB114NM)..
DISTRIBUTION AND EXTENT: Truehill soils are of small extent on the Highland section of the Basin and Range province in northcentral New Mexico. The MLRA is 36.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Santa Fe County, New Mexico; Santa Fe Area Soil Survey Update; 2008. Truehill is a coined name.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon- The zone from the soil surface to a depth of about 12 inches. (A through Btk horizons)
Argillic horizon- The zone from 4 to 12 inches. (Bt and Btk horizons)
Calcic Horizon- The zone from 12 to 67 inches (Bk1, Bk2, Bk3, and Bk4 horizons)
Particle-size control section- The zone from 4 to 12 inches. (Bt and Btk horizons)
The 12/2006 revision changes the classification from Ustic Calciargids to Calcidic Argiustolls.
Taxonomic version: Classified according to Keys to Soil Taxonomy, Tenth Edition, 2006.