LOCATION RIOVISTA NMEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed, mesic Ustic Torriorthents
TYPICAL PEDON: Riovista gravelly loamy sand--on a 1 percent slope to the southwest at 6,750 feet elevation--urban open-space land. (Colors are for dry soil unless otherwise noted. When described, the soil was dry from the surface to 4 inches and slightly moist below 4 inches.)
A--0 to 3 inches; brown (7.5YR 5/3) gravelly loamy sand, brown (7.5YR 4/3) moist; weak medium granular structure; soft, very friable, nonsticky and nonplastic; few fine and common very fine roots; few very fine irregularly shaped pores; 25 percent gravel and 5 percent cobbles; strongly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (2 to 5 inches thick)
C1--3 to 8 inches; brown (7.5YR 5/4) gravelly sand, brown (7.5YR 4/3) moist; single grain; loose, nonsticky and nonplastic; few fine and common very fine roots; 20 percent gravel, 10 percent cobbles, and 2 percent stones; slightly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (5 to 12 inches thick)
C2--8 to 16 inches; brown (7.5YR 5/3) very gravelly coarse sand, brown (7.5YR 4/3) moist; single grain; loose, nonsticky and nonplastic; few coarse, few medium, few fine, and few very fine roots; 45 percent gravel, 10 percent cobbles, and 2 percent stones; slightly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (7 to 13 inches thick)
C3--16 to 35 inches; brown (7.5YR 5/4) extremely cobbly coarse sand, brown (7.5YR 4/3) moist; single grain; loose, nonsticky and nonplastic; few coarse, few medium, few fine, and common very fine roots; 45 percent gravel, 30 percent cobbles, and 5 percent stones; very slightly effervescent; slightly alkaline (pH 7.4); gradual wavy boundary. (7 to 19 inches thick)
C4--35 to 53 inches; brown (7.5YR 5/4) extremely gravelly loamy coarse sand, brown (7.5YR 4/3) moist; single grain; loose, nonsticky and nonplastic; few coarse, few medium, common fine, and common very fine roots; one lens (up to 4 inches thick) of gravelly coarse sand; 50 percent gravel, 20 percent cobbles, and 2 percent stones; neutral (pH 7.2); clear wavy boundary. (12 to 32 inches thick)
C5--53 to 61 inches; reddish brown (5YR 5/3) gravelly loamy sand, reddish brown (5YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; 20 percent gravel and 5 percent cobbles; neutral (pH 7.2); clear wavy boundary. (8 to 26 inches thick)
C6--61 to 95 inches; reddish brown (5YR 5/4) stratified gravelly coarse sand and loamy sand, reddish brown (5YR 4/4) moist; massive; soft, very friable, nonsticky and nonplastic; 5 to 30 percent gravel; slightly alkaline (pH 7.4).
TYPE LOCATION: Santa Fe County, New Mexico; about 2 miles west-southwest of downtown Santa Fe within the nonsectionized Santa Fe Grant; USGS Santa Fe 7.5 minute topographic quadrangle; Latitude 35 degrees 40 minutes 35 seconds North and Longitude 105 degrees 58 minutes 44 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 torric (aridic) bordering on ustic.
Mean annual soil temperature - 52 to 54 degrees F.
Lithology of rock fragments: granite, gneiss, and schist
Particle-size control section (weighted averages)
Silicate clay content: 0 to 8 percent
Rock fragment content: 35 to 60 percent
Reaction - moderately alkaline in the surface and upper part of the underlying material; neutral to slightly alkaline in the lower part of the underlying material
Salinity, mmhos/cm - 0 to 1
Sodicity, SAR - 0 to 1
A horizon
Value: 4 through 6 dry, 3 or 4 moist
Chroma: 3 or 4, dry or moist
Rock fragments: total range is 20 to 35 percent
15 to 25 percent gravel
5 to 10 percent cobbles
Upper C horizons
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4, dry or moist
Texture: gravelly sand, very gravelly coarse sand, very cobbly coarse sand, and extremely cobbly coarse sand
Rock fragments: total range is 25 to 90 percent, averaging 30 to 55 percent with:
25 to 40 percent gravel
5 to 10 percent cobbles
0 to 5 percent stones
Middle C horizons
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4, dry or moist
Texture: very gravelly loamy sand,extremely gravelly loamy coarse sand, gravelly loamy sand, extremely cobbly loamy sand, extremely cobbly coarse sand
Rock fragments: total range is 40 to 85 percent, averaging 55 to 80 percent with:
40 to 50 percent gravel
15 to 45 percent cobbles
0 to 5 percent stones
Lower C horizons
Hue: 5YR or 7.5YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 through 6, dry or moist
Texture: stratified gravelly coarse sand to loamy sand
Rock fragments: total range is 5 to 35 percent, averaging 10 to 25 percent with:
10 to 20 percent gravel
0 to 5 percent cobbles
COMPETING SERIES: These are the Calicott (T), Mathis, and Tsetaa (T) series. Calicott soils have mean annual soil temperatures of 49 to 52 degrees F.. Mathis soils are moderately deep to bedrock. Tsetaa soils have rock fragments dominated by sandstone channers and flagstones.
GEOGRAPHIC SETTING: Riovista soils are on flood plain steps of valley floors. They formed in alluvium derived from Precambrian granite, gneiss, and schist over residuum derived from Tertiary granitic sandstone. Slopes are 0 to 2 percent. Elevation ranges from 5,400 to 6,900 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 Chupe, Delvalle, and Devargas soils. Chupe soils are sandy and occur on narrow flood plains. Delvalle soils are coarse-loamy, have B horizons with identifiable secondary carbonates, and occur on treads of high stream terraces. Devargas soils are fine-loamy over sandy or sandy-skeletal, have argillic horizons, and occur on treads of high stream terraces.
DRAINAGE AND PERMEABILITY: Excessively drained; negligible surface runoff; rapid or very rapid permeability. These soils are estimated to have a rare flooding frequency.
USE AND VEGETATION: Riovista soils are used for limited urban development, a sand and gravel source, livestock grazing, and recreation. The historic climax vegetation is New Mexico feathergrass, blue grama, black grama, galleta, sideoats grama, oneseed juniper, and twoneedle pinyon. The ecological site is Gravelly(R036XB114NM).
DISTRIBUTION AND EXTENT: Riovista soils are of small extent on the southeastern Espanola Basin part 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. The name is coined from the Spanish words for river and view.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to a depth of about 3 inches (A horizon).
This soil was determined to be an Orthent due to its regular decrease of organic carbon with depth and no evidence of recent material deposition.
Particle-size control section - The zone from 10 to 40 inches (part of C2, C3, part of C4 horizons)
Series control section - The zone from 0 to 60 inches.
Taxonomic version: Classified according to Keys to Soil Taxonomy, Tenth Edition, 2006.