LOCATION VENPORT                 AZ

Established Series
Rev. JMH/CRF/MJA
02/2025

VENPORT SERIES

The Venport series consists of very deep, poorly drained soils that formed in lacustrine deposits derived from basalt. Venport soils are on playas. Slopes range from 0 to 2 percent. Mean annual precipitation is about 22 inches and the mean annual temperature is about 47 degrees F.

TAXONOMIC CLASS: Fine, smectitic, mesic Typic Argiaquolls

TYPICAL PEDON: Valspring-Venport complex (Colors are for dry soil unless otherwise noted.)

A--0 to 3 inches (0 to 7 cm); dark grayish brown (10YR 4/2) clay, dark brown (7.5YR 3/2) moist; moderate medium subangular blocky; extremely hard, extremely firm, very sticky, very plastic; few very fine and fine dendritic tubular pores; many very fine roots throughout; no fragments noneffervescent; neutral (pH 7.2); many fine prominent threadlike masses of oxidized iron; clear smooth boundary

AB--3 to 6 inches (7 to 15 cm); brown (7.5YR 4/2) clay, dark brown (7.5YR 3/3) moist; moderate medium subangular blocky; moderately hard, extremely firm, very sticky, very plastic; many very fine roots throughout; no fragments; noneffervescent; neutral (pH 7.2); many fine prominent threadlike masses of oxidized iron; clear smooth boundary

Bt1--6 to 16 inches (15 to 41 cm); brown (7.5YR 4/2) clay, dark brown (7.5YR 3/2) moist; strong medium angular blocky; very hard, extremely firm, very sticky, very plastic; few very fine roots throughout; 20 percent distinct clay films on all faces of peds; no fragments; noneffervescent; neutral (pH 7.2); gradual smooth boundary

Bt2--16 to 31 inches (41 to 79 cm); brown 7.5YR 4/2 clay, dark brown (7.5YR 3/2) moist; strong medium angular blocky; very hard, extremely firm, very sticky, very plastic few very fine roots throughout; 20 percent distinct clay films on all faces of peds; no fragments; noneffervescent; neutral (pH 7.2); gradual smooth boundary

Btss1--31 to 45 inches (79 to 115 cm); brown (7.5YR 4/3) clay, dark brown (7.5YR 3/3) moist; strong medium angular blocky; very hard, extremely firm, very sticky, very plastic; few very fine roots throughout; 20 percent distinct clay films on all faces of peds; no fragments; noneffervescent; slightly alkaline (pH 7.4); gradual smooth boundary

Btss2--45 to 50 inches (115 to 128 cm); brown (7.5YR 4/3) clay, brown (7.5YR 4/4) moist; strong medium angular blocky; very hard, extremely firm, very sticky, very plastic; 20 percent distinct clay films on all faces of peds; no fragments; noneffervescent; slightly alkaline (pH 7.6); many coarse distinct irregular masses of oxidized iron, few faint irregular masses of reduced iron

TYPE LOCATION: Coconino County, Arizona; located about 17.4 kilometers (10.7 miles) southwest of Parks, Arizona; USGS Quadrangle Davenport Hill; Latitude 35.12631, Longitude -112.04150, Datum WGS84

RANGE IN CHARACTERISTICS:
Soil moisture regime: aquic
Mean annual soil temperature: 45 to 49 degrees F
Rock fragment content: 0 to 2 percent
Depth to lithic contact: over 150 centimeters
Particle-size control section:
Clay content: 45 to 60 percent

A horizon
Hue: 7.5YR or 10YR
Value: 3 or 4 (2 or 3 moist)
Chroma: 2 or 3, dry or moist
Calcium carbonate equivalent: 0 to 2 percent
Reaction: neutral or slightly alkaline

B horizon
Hue: 7.5YR or 10YR
Value: 4 or 5 (3 or 4 moist)
Chroma: 2 to 4, dry or moist
Texture: clay
Calcium carbonate equivalent: 0 to 2 percent
Sodium Adsorption Ratio (SAR): 0 to 2
Reaction: neutral or slightly alkaline

COMPETING SERIES: These are the Bremer, Crossplain, Gregory, and Worthenton soils.
Bremer soils have an annual precipitation that exceeds 30 inches, and are more consistently moist in May and June
Crossplain have carbonates within a depth of 152 centimeters (60 inches)
Gregory soils are dry at depths between 10 and 30 centimeters (4 to 12 inches) for 70 to 100 consecutive days after the summer solstice and are more consistently moist in May and June
Worthenton soils have a mollic epipedon less than 60 centimeters (24 inches) thick and are more consistently moist in May and June

GEOGRAPHIC SETTING:
Parent material: lacustrine deposits from basalt
Landform: playas
Slopes: 0 to 2 percent
Elevation: 6,500 to 7,600 feet
Mean annual air temperature: 45 to 49 degrees F
Mean annual precipitation: 20 to 24 inches
Precipitation peaks in July and August, and in winter months. May and June are much drier.
Frost-free period: 100 to 120 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Valspring and Pinespring soils. Valspring and Pinespring soils have no aquic feature. Valspring soils are on upland lucastrine positions. Pinespring soils are in alluvial stream beds and terrace locations.

DRAINAGE AND PERMEABILITY: poorly drained, very slow permeability

USE AND VEGETATION: These soils are used principally as habitat. Native vegetation is mainly cattail, and sedge. Golden tickseed and spike muhly are found in some locations.

DISTRIBUTION AND EXTENT: Northern Arizona. MLRA 39.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.

SERIES ESTABLISHED: Coconino County, Arizona, small extent.

REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: from 0 to 115 centimeters. (A and B horizons)
Argillic horizon: from 15 to 65 centimeters. (B horizons).
Redox features: at less than 7 centimeters.
Name is derived from Davenport Lake, Arizona
Taxonomic Version: Keys to Soil Taxonomy, Thirteenth Edition, 2022
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National Cooperative Soil Survey
U.S.A.