LOCATION PONIL                   NM

Established Series
Rev. TEH/BDS/KLS
08/2022

PONIL SERIES

The Ponil series consists of deep or very deep well drained soils that formed in colluvial deposits derived from sandstone and shale. These soils are on sides of mountains and slopes are 10 to 35 percent. Mean annual precipitation is about 460 mm, and mean annual air temperature is about 6 degrees C.

TAXONOMIC CLASS: Fine, smectitic, frigid Vertic Paleustalfs

TYPICAL PEDON: Ponil stony loam, rangeland. (Colors are for dry soil unless otherwise noted.)

Oi--0 to 1 cm; undecomposed forest litter.

Oe--1 to 3 cm; partially decomposed forest litter. (Combined thickness of O horizons - 0 to 5 cm)

A--3 to 13 cm; grayish brown (10YR 5/2) stony loam, dark brown (10YR 3/3) moist; weak very fine granular structure; slightly hard, firm, slightly sticky, plastic; many fine and very fine roots; many fine and very fine pores; 15 percent rock fragments; slightly alkaline; clear smooth boundary. (5 to 15 cm thick)

Bt1--13 to 41 cm; light yellowish brown (10YR 6/4) clay, yellowish brown (10YR 5/4) moist; moderate fine and medium angular blocky structure; very hard, very firm, sticky, very plastic; common fine and very fine roots; few very fine tubular pores; many thick clay films on peds; about 5 percent rock fragments; slightly acid; clear smooth boundary.

Bt2--41 to 64 cm; pale brown (10YR 6/3) clay, yellowish brown (10YR 5/4) moist; many distinct light yellowish brown (10YR 6/4) mottles, yellowish brown (10YR 5/4) moist; moderate coarse prisms parting to moderate coarse angular and subangular blocky structure; very hard, very firm; sticky, very plastic; common fine and coarse roots; few fine tubular pores; many thick clay films on peds; about 5 percent rock fragments; moderately alkaline; gradual smooth boundary. (Combined thickness of Bt horizons - 40 to 75 cm)

C--64 to 155 cm; light gray (5Y 7/2) clay, light olive gray (5Y 6/2) moist; many distinct mottles of light yellowish brown (10YR 6/4), yellowish brown (10YR 5/6) moist; massive; very hard, very firm, sticky, very plastic; common fine and coarse roots; common medium tubular pores; many pressure faces; 10 percent rock fragments, weakly calcareous; moderately alkaline.

TYPE LOCATION: Colfax County, New Mexico; about 6 km west of Cimarron; about 1035 meters west and 120 meters north of gaging station number 6607 on Cimarron Creek.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--5 to 8 degrees C
Mean summer soil temperature--16 to 18 degrees C
Solum thickness--45 cm to 85 cm
Paralithic contact--more than 100 cm to interbedded sandstone and shale bedrock

Particle-size control section:
Rock fragment content--5 to 25 percent by volume

A horizon
Value--4 through 6 dry, 2 through 4 moist
Chroma--2 through 4
Texture--loam, sandy clay loam, or clay loam
Rock fragment content--5 to 35 percent total; 15 to 35 percent stones
Reaction--pH 6.1 to 7.8

Bt1 horizon
Hue--7.5YR or 10YR
Value--4 through 6 dry, 4 or 5 moist
Chroma--3 or 4
Texture--clay or silty clay
Rock fragment content--5 to 25 percent
Structure--moderate to strong subangular and angular blocky
Reaction--pH 6.1 to 8.4

Bt2 horizon
Hue--10YR or 2.5Y
Value--4 through 6 dry, 3 through 5 moist
Chroma--2 or 3
Mottles--common distinct mottles in some pedons, with chroma of 4 through 6
Reaction--pH 6.1 to 8.4

C horizon
Hue--10YR, 2.5Y or 5Y
Chroma--4 through 6
Mottles--common distinct mottles in most pedons, with chroma of 4 through 6
Reaction--pH 6.1 to 8.4

COMPETING SERIES: These are the Crow, Dargol, Depew, Fuera, Lakoa, Lubrecht and Ordnance series. Crow soils have strong prismatic structure in the B horizon and an AB horizon. Dargol, Lakoa, Lubrecht and Ordnance soils have bedrock at depths of 50 to 100 cm. Depew soils have an AB horizon. Fuera soils have more than 15 percent rock fragments in the control section.

GEOGRAPHIC SETTING:
Landform--sides of mountains
Elevation--2125 to 2600 meters
Slope--10 to 35 percent
Parent material--colluvial deposits derived from sandstone and shale
Climate--continental
Mean annual precipitation--410 to 480 mm with about 60 percent falling during the frost-free season
Mean annual air temperature--4 to 7 degrees C
Mean summer temperature--14 to 17 degrees C

GEOGRAPHICALLY ASSOCIATED SOILS: None listed

DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; very slow permeability.

USE AND VEGETATION: Used for native range, wildlife habitat, recreation, and watershed. Principal vegetation is pinyon, juniper, oak, mountain mahogany, blue grama, little bluestem, mountain muhly and western wheatgrass.

DISTRIBUTION AND EXTENT: Ponil soils are moderately extensive in the mountains of northern New Mexico; MLRA 48A

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

SERIES ESTABLISHED: Colfax County, New Mexico, 1974

REMARKS: Ponil soils were formerly classified in the fine, mixed family of Typic Eutroboralfs.

Converted to metric, updated formatting, and O horizons were updated to start at zero. 8/2022

ADDITIONAL DATA: Lincoln Laboratory 66L602

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National Cooperative Soil Survey
U.S.A.