LOCATION WASHPASS NMEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Ustic Argicryolls
TYPICAL PEDON: Washpass fine sandy loam, stony -- on a convex footslope sloping 33 percent to the northeast at 8,960 feet elevation -- forest. (Colors are for dry soil unless otherwise noted. When described, the soil was dry throughout.)
Oi-- 0 inches to 2; forest litter of leaves, needles and twigs; abrupt smooth boundary. (1 to 3 inches thick)
A-- 2 to 8 inches; brown (7.5YR 4/2) fine sandy loam, dark brown (7.5YR 3/2) moist; moderate medium granular structure; soft, very friable, slightly sticky and nonplastic; few coarse, common medium, few fine, and common very fine roots; common very fine irregularly shaped pores; 5 percent pebbles and less than 1 percent stones; moderately acid (pH 6.0); clear smooth boundary. (2 to 6 inches thick)
BA-- 8 to 14 inches; brown (7.5YR 5/2) fine sandy loam, dark brown (7.5YR 3/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; few coarse and medium and common fine and very fine roots; few fine and common very fine tubular pores; 5 percent pebbles; moderately acid (pH 6.0); gradual smooth boundary. (3 to 9 inches thick)
Bt/E1-- 14 to 28 inches; brown (7.5YR 4/4) with pinkish gray (7.5YR 6/2) fine sandy loam, dark brown (7.5YR 3/4) with brown (7.5YR 4/3) moist; moderate coarse subangular structure; slightly hard, friable, slightly sticky and nonplastic; few coarse to fine and common very fine roots; common fine and very fine tubular pores; common bleached sand and silt grains (skeletans) on faces of peds; few thin clay films on faces of peds and in pores; 10 percent pebbles; slightly acid (pH 6.2); clear wavy boundary. (6 to 16 inches thick)
Bt/E2-- 28 to 38 inches; brown (7.5YR 4/4) with light brown (7.5YR 6/4) gravelly fine sandy loam, dark brown (7.5YR 3/4) with brown (7.5YR 4/4) moist; moderate coarse subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; few coarse to fine, and common very fine roots; common fine and very fine tubular pores; common bleached sand and silt grains (skeletans) on faces of peds; common thin clay films on faces of peds and in pores; 15 percent pebbles and 5 percent cobbles; slightly acid (pH 6.2); clear wavy boundary. (10 to 20 inches thick)
Bt1-- 38 to 59 inches; brown (7.5YR 5/4) very gravelly fine sandy loam, dark brown (7.5YR 3/4) moist; moderate medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few fine and few very fine roots; few fine and common very fine tubular pores; few moderately thick clay films on faces of peds and common thin clay films on faces of peds and on rock fragments; 30 percent pebbles, 10 percent cobbles, and 5 percent stones; slightly acid (pH 6.2); clear wavy boundary. (8 to 25 inches thick)
Bt2-- 59 to 75 inches; brown (7.5YR 5/4) very fine sandy loam, brown (7.5YR 4/4) moist; weak coarse subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; few fine and few very fine roots; common fine and few very fine tubular pores; few moderately thick clay films on faces of peds and few thin clay films on faces of peds and on rock fragments; 5 percent pebbles; slightly acid (pH 6.4); clear wavy boundary. (0 to 22 inches thick)
Bt3-- 75 to 87 inches; brown (7.5YR 5/4) gravelly fine sandy loam, weak medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; few fine and few very fine roots; few fine and few very fine tubular pores; few thin clay films on faces of peds and on rock fragments; 20 percent pebbles; slightly acid (pH 6.4).
TYPE LOCATION: San Juan County, New Mexico; on the Navajo Indian Reservation about 9 miles west-southwest of Sheep Springs; 1,450 feet south and 700 feet east of the northwest corner of sec. 34, T.22N., R.19W.; Latitude 36 degrees 6 minutes 1 second N and Longitude 108 degrees 51 minutes 36 seconds W.
RANGE IN CHARACTERISTICS:
Soil moisture - Typically, the soil moisture control section (SMCS) is moist in all parts from January to May and intermittently moist in some part from June to December. The SMCS is moist in all parts greater than 40 percent of the time (cumulative), when the soil temperature at 20 inches is 41 degrees F or higher. Typic ustic moisture regime.
Soil temperature - 37 to 39 degrees F.
Mean summer soil temperature - 44 to 47 degrees F.
Reaction - medium acid or slightly acid
Silicate clay content, control section weighted average - 10 to 18 percent
Rock fragment content, control section weighted average - 10 to 35 percent
Organic carbon content in Mollic epipedon - 0.6 to 2.3 percent
Depth to base of Argillic horizon - 60 inches or more
A horizon
Value: 3 or 4 dry, 2 or 3 moist.
Chroma: 2 or 3.
Rock fragments: Total range is 0 to 15 percent; 0 to 10 percent pebbles; 0 to 5 percent cobbles; 1 to 3 percent stones.
BA horizon
Value: 3 through 5 dry, 2 or 3 moist.
Chroma: 2 or 3.
Rock fragments: Total range is 0 to 15 percent; 0 to 10 percent pebbles; 0 to 5 percent cobbles; 0 to 3 percent stones.
Bt/E horizons
7.5YR or 10YR.
Value: 4 or 5 dry, 3 or 4 moist.
Chroma: 2 through 4.
Texture: fine sandy loam, gravelly fine sandy loam, or gravelly sandy loam.
Clay content: 10 to 18 percent.
Rock fragments: Total range is 10 to 35 percent; 10 to 20 percent pebbles; 0 to 10 percent cobbles; 0 to 5 percent stones
2Bt horizon
Hue: 7.5YR or 10YR.
Value: 5 or 6 dry, 3 through 5 moist.
Chroma: 2 through 4.
Texture: very gravelly fine sandy loam or very gravelly sandy loam. Clay content: 14 to 18 percent.
Rock fragments: Total range is 35 to 60 percent; 30 to 40 percent pebbles; 5 to 15 percent cobbles; 0 to 5 percent stones
3Bt horizons
Hue: 7.5YR or 10YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 2 through 4.
Texture: gravelly fine sandy loam, gravelly sandy loam, or very fine sandy loam.
Clay content: 10 to 18 percent.
Rock fragments: Total range is 5 to 30 percent; 5 to 20 percent pebbles; 0 to 5 percent cobbles; 0 to 5 percent stones
COMPETING SERIES: These are the Bassel (CO), Burgess (WY), Ethelman (CO), Greenman (WY), Opitz (MT), Spinney (CO), and Tiagos (CO) series. Bassel soils have high amounts of medium and coarse angular sand and fine granite pebbles, and have horizons with continuous accumulations of secondary calcium carbonates within 40 inches of the surface. Spinney soils have non-contrasting sandy-skeletal substrata above a depth of 40 inches. In addition, Spinney contains carbonates within 40 inches. Burgess, Ethelman, and Greenman soils have bedrock within 40 inches. Opitz soils are moderately deep to grus and deep to hard bedrock. Tiagos soils have mean summer soil temperatures of 48 to 58 degrees F, are neutral or mildly alkaline, and receive less total precipitation.
GEOGRAPHIC SETTING: Washpass soils are on north-facing footslopes and backslopes of hills, buttes, and escarpments. They formed in colluvium derived from Tertiary basalt and tuff-breccia. Slopes are 25 to 70 percent. Elevation ranges from 8,200 to 9,800 feet. The mean annual precipitation is 20 to 24 inches with more than 50 percent falling as snow from winter storms. The mean annual temperature is 39 to 41 degrees F. The average frost-free period is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Owlspring (T), Sonsela (T), Todacheene (T), and Viewpoint soils. Owlspring soils are fine-silty, somewhat poorly drained, and occur on toeslopes. Todacheene soils are fine-loamy, have thick mollic epipedons, and occur on footslopes and fan terraces. Viewpoint soils are shallow to basalt, and occur on adjacent shoulders. Sonsela soils are loamy-skeletal, lack mollic epipedons, and occur on adjacent south-facing backslopes.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately rapid permeability
USE AND VEGETATION: Washpass soils are used for timber production and livestock grazing. Present vegetation is quaking aspen, Douglas fir, and corkbark fir with an understory of Kentucky bluegrass, earth sedge, nodding bromegrass, mountain snowberry, Oregongrape, and wild strawberry.
DISTRIBUTION AND EXTENT: Washpass soils are of small extent on the Defiance Uplift-Chuska Mountains portion of the Colorado Plateau province in northwest New Mexico and northeast Arizona. MLRA 35.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: San Juan County, New Mexico, Shiprock Area Soil Survey, 1993. Washpass is a coined name derived from Washington Pass in the Chuska Mountains.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to a depth of about 14 inches. (A and BA horizon)
Argillic horizon - The zone from 14 to about 87 inches. (Bt/E1, Bt/E2, Bt1, Bt2 and Bt3 horizons)
Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy Tenth Edition, 2006.
ADDITIONAL DATA: Organic carbon content determined by Inter-Mountain Laboratories, Inc. A soil similar to Washpass was sampled for the NSSL in 1986 in the Fort Defiance soil survey area. It was given the name Washpass and sampled as pedon # S86-NM-045-004. The taxonomic classification of that soil is different from this current proposal.