LOCATION VENSON WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic Andic Dystrocryepts
TYPICAL PEDON: Venson gravelly ashy sandy loam, on a north facing 50 percent slope at an elevation of 5,700 feet in a subalpine fir and Engelmann spruce forest. (Colors are for dry soil sunless otherwise stated. All textures are apparent field textures.)
Oe--0 to 1 inch; moderately decomposed needles and twigs; abrupt smooth boundary. (1 to 3 inches thick)
A--1 to 5 inches; reddish brown (5YR 4/3) gravelly ashy sandy loam, dark reddish brown (5YR 3/3) moist; weak fine granular structure; soft, very friable, nonsticky, nonplastic and weakly smeary; common very fine and fine and few medium roots; common very fine and fine irregular pores; 15 percent gravel; slightly acid (pH 6.2); clear smooth boundary. (3 to 5 inches thick)
Bw--5 to 12 inches; reddish brown (5YR 4/4) gravelly ashy sandy loam, dark reddish brown (5YR 3/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky, nonplastic and weakly smeary; common very fine and fine and few medium roots; common very fine and fine irregular pores; 20 percent gravel and 5 percent cobbles; slightly acid (6.2); clear wavy boundary. (7 to 14 inches thick)
2C1--12 to 29 inches; reddish brown (2.5YR 5/3) very gravelly sandy loam, reddish brown (2.5YR 4/3) moist; massive; soft, very friable. nonsticky and nonplastic; common very fine and fine roots; few fine irregular pores; 40 percent angular gravel and 5 percent angular cobbles; slightly acid (pH 6.4); clear wavy boundary.
2C2--29 to 39 inches; reddish brown (2.5YR 5/3) extremely gravelly sandy loam, reddish brown (2.5YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots in the upper part; 60 percent angular pebble and 10 percent angular cobbles; slightly acid (pH 6.4); (combined 2C horizon thickness is 13 to 30 inches thick)
2R--39 inches; red sandstone
TYPE LOCATION: Okanogan County, Washington; about 4 miles north of Mazama, Wa., 400 feet east and 1,300 feet north of the southwest corner of section 6, T. 37 N., R. 20 E. (Latitude 48 degrees, 38 minutes, 49 seconds N., Longitude 120 degrees, 24 minutes, 02 seconds W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 37 to 41 degrees F. Mean summer soil temperature ranges from 42 to 46 degrees F. These soils are usually moist but are dry in all parts of the moisture control section for 30 to 45 consecutive days following the summer solstice. Thickness of the volcanic ash is 7 to 14 inches, and has an estimated moist bulk density of 0.75 to 0.90 g/cc, volcanic glass content of 30 to 60 percent, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 1.0 to 2.0 percent, and 15-bar water retention of 8 to 12 percent for air dried samples. The particle-size control section averages 40 to 70 percent rock fragments and 5 to 15 percent clay. Depth to bedrock is 20 to 40 inches. Reaction is slightly acid to neutral throughout.
The A horizon has hues of 5YR, 7.5YR and 2.5YR, values of 4 or 5 dry, 3 or 4 moist, and chromas of 2 or 3 dry or moist.
The Bw horizon has hues of 5YR and 2.5YR, values of 4 to 6 dry, 3 or 4 moist, and chromas of 3 or 4 dry or moist. It has 15 to 25 percent gravel and 0 to 5 percent cobbles.
The 2C horizons have hues 5YR and 2.5YR, values of 4 or 5 dry, 3 or 4 moist, and chromas of 2 to 4 dry or moist. It is very gravelly sandy loam, extremely gravelly sandy loam or very cobbly sandy loam. It has 40 to 70 percent gravel and 0 to 20 percent cobbles
COMPETING SERIES: These are the McCay, Prouty, Skinwood, Smokejump, Twentymile and Vandamine series. McCay soils are 40 to 60 inches deep to bedrock. Skinwood soils have medial texture modifiers. Twentymile soils have densic material at 20 to 35 inches. Prouty soils are moderately deep to a paralithic contact. Smokejump soils have hue of 10YR only.
GEOGRAPHIC SETTING: Venson soils are on backslopes and shoulders of mountains and have slopes of 35 to 65 percent. These soils formed in colluvium and residuum from sedimentary rock of the Ventura member of the Midnight Peak formation. The volcanic ash mantle is 7 to 14 inches thick. Elevations range from 4,800 to 6,500 feet. The climate is characterized by cool, dry summers and cold, wet winters. Average annual precipitation is 35 to 40 inches. The average January temperature ranges from 18 to 22 degrees F., and the average July temperature ranges from 52 to 58 degrees F. Average annual temperature is 37 to 41 degrees F. The frost-free season is 70 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gatewall, Ortellcreek, Volmont and Winsand series. The Gatewall soils are on footslopes and backslopes and are very deep formed in glacial till. Ortellcreek soils are on footslopes and backslopes and are very deep with an argillic horizon. Volmont soils are on upper backslopes, shoulders and ridges and have a vitrandic ash mantle. Winsand soils are backslopes with southerly aspects with a vitrandic ash mantle.
DRAINAGE AND PERMEABILITY: Well drained, rapid runoff; moderately rapid permeability.
USE AND VEGETATION: Used for wildlife habitat, recreation and watershed. Native vegetation is subalpine fir and Engelmann spruce with an understory of blue huckleberry, grouse huckleberry, cascades azalea, sidebells wintergreen, western rattlesnake plantain, and mountainlover.
DISTRIBUTION AND EXTENT: Northcentral Washington. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Okanogan National Forest, Okanogan County, Washington, 2005.
REMARKS: Diagnostic horizons and features in this pedon include:
Ochric epipedon
Cambic horizon formed in volcanic ash - 5 to 12 inches (Bw horizon)
Lithic contact - 39 inches (R horizon)
PSCS - zone from 11 to 39 inches (Part of Bw, 2C1 and 2C2 horizon)
Udic soil moisture regime.
Andic properties from 1 to 12 inches.