LOCATION ROCIO                   NM

Established Series
Rev. TEH/JBC/KLS
09/2022

ROCIO SERIES

The Rocio series consists of deep, well drained soils that formed in alluvial and colluvial deposits derived from sandstone and shale. Rocio soils are on mountains and have slopes of 15 to 65 percent. The mean annual precipitation is about 690 mm and the mean annual air temperature is about 4 degrees C.

TAXONOMIC CLASS: Fine, mixed, superactive, frigid Typic Paleustalfs

TYPICAL PEDON: Rocio gravelly fine sandy loam, forested. (Colors are for dry soil unless otherwise noted.)

Oe--0 to 3 cm; partially decomposed forest litter. (1 to 5 cm thick)

A--3 to 16 cm; dark grayish brown (10YR 4/2) gravelly fine sandy loam, very dark grayish brown (10YR 3/2) moist; soft, friable, slightly plastic; many fine and very fine roots; many fine interstitial pores; 20 percent fine pebbles, 5 percent cobbles; slightly acid; clear smooth boundary. (8 to 15 cm thick)

E--16 to 49 cm; pale brown (10YR 6/3) gravelly fine sandy loam, brown (10YR 4/3) moist; massive; soft, very friable; common fine, medium and coarse roots; common fine tubular pores; 30 percent fine pebbles; slightly acid; abrupt wavy boundary. (Combined thickness of A1 and A2 horizons-20 to 55 cm)

Bt1--49 to 102 cm; brown (7.5YR 5/4) clay, brown (7.5YR 4/4) moist; strong medium blocky structure; very hard, very firm, slightly sticky and very plastic; many medium roots; few fine tubular pores; continuous thick clay films on surfaces of peds and in pores; 5 percent pebbles and cobbles; slightly acid; gradual wavy boundary. (25 to 55 cm thick)

Bt2--102 to 163 cm; light brown (7.5YR 6/4) clay, brown (7.5YR 4/4) moist; strong coarse blocky structure that parts to moderate fine and medium blocky; very hard, very firm, slightly sticky and very plastic; few fine and medium roots; few fine tubular pores; continuous thick clay films on surfaces of peds and rock fragments, many pressure faces on secondary peds; 10 percent rock fragments; slightly acid.

TYPE LOCATION: San Miguel County, New Mexico; about 2415 meters southeast of the Village of Rociada, or if section lines are projected from the Santa Fe National Forest, 185 meters south and 245 meters east of the NW corner section 6, T.18N., R.15E.

RANGE IN CHARACTERISTICS:
Solum thickness--more than 100 cm
Rock fragment content--5 to 30 percent gravel, cobbles, channers and flagstones of sandstone lithology
Reaction--pH 6.1 to 7.3
Some pedons lack an O horizon

A horizon
Hue--7.5YR or 10YR
Value--4 or 5 dry, 3 or 4 moist
Chroma--2 or 3
Texture--loam or sandy loam
Rock fragment content--5 to 25 percent gravel and 0 to 10 percent cobbles

E horizon
Hue--7.5YR or 10YR
Value--5 through 7
Chroma--3 or 4
Texture--loam or fine sandy loam
Rock fragment content--5 to 15 percent gravel and 0 to 5 percent cobbles

Bt horizons
Hue--5YR through 10YR
Value--4 through 6
Chroma--3 through 6
Texture--clay or sandy clay
Clay content--45 to 60 percent
Rock fragment content--0 to 10 percent cobbles, channers or flagstones

COMPETING SERIES: These are the Burnac, Hogg, and Mirand series. Burnac soils have a montmorillonitic mineralogy. Hogg soils have a lithic contact at depths of 100 to 150 cm. Mirand soils lack an E horizon and receive less precipitation.

GEOGRAPHIC SETTING:
Landform--convex mountain slopes
Elevation--2125 to 3050 meters
Slope--15 to 65 percent
Parent Material--alluvial and colluvial deposits derived from sandstone and shale
Mean annual precipitation--635 to 760 mm of which 2/3 is received during the period of May through September
Mean annual air temperature--3 to 6 degrees C
Mean annual summer temperature--9 to 11 degrees C
Frost free period--100 to 120 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed

DRAINAGE AND PERMEABILITY: Well drained; slow permeability

USE AND VEGETATION: These soils are used for woodland, wildlife, recreation, and watershed. Native vegetation is ponderosa pine, Douglas fir, white fir, and oak with an understory of Arizona fescue, mountain muhly, and pine dropseed.

DISTRIBUTION AND EXTENT: Rocio soils are moderately extensive in the mountainous areas of central and northern New Mexico; MLRA 48A

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Las Vegas Area, San Miguel County, New Mexico, 1977

REMARKS: Converted to metric, updated formatting, and O horizons were updated to start at zero. Competing series section was not updated. 7/2022

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National Cooperative Soil Survey
U.S.A.