LOCATION IMPEDIMENTA CA
Established Series
Rev: PBF/CAH/ET
04/2015
IMPEDIMENTA SERIES
The Impedimenta series consists of very shallow, somewhat excessively drained soils that formed from dominantly granitoid residuum. Impedimenta soils are on pediments, hills and mountain backslopes. Slopes range from 4 to 30 percent. The mean annual precipitation is about 100 millimeters (4 inches) and the mean annual air temperature is about 21.5 degrees C (71 degrees F).
TAXONOMIC CLASS: Mixed, hyperthermic Lithic Torripsamments
TYPICAL PEDON: Impedimenta gravelly loamy sand, on a north northwest-facing, convex, 16 percent slope under desert shrubs at an elevation of 645 meters (2,090 feet). (Colors are for dry soil unless otherwise noted.) The surface is covered by approximately 15 percent fine gravel, 55 percent medium and coarse gravel, 8 percent cobbles, and 1 percent stones.
A -- 0 to 2 centimeters (0 to 1 inch); yellowish brown (10YR 5/4) gravelly loamy sand, brown (10YR 5/3) moist; weak thin platy structure; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; few fine vesicular and common fine interstitial pores; 15 percent fine gravel and 10 percent medium and coarse gravel; strongly effervescent; moderately alkaline (pH 8.2); abrupt wavy boundary. (1 to 3 centimeters thick)
C -- 2 to 10 centimeters (1 to 4 inches); very pale brown (10YR 7/4) gravelly sand, pale brown (10YR 6/3) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine and very few coarse roots; 15 percent fine gravel and 5 percent medium and coarse gravel; strongly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (0 to 15 centimeters thick)
R -- 10 centimeters (4 inches); unweathered, slightly fractured granitic bedrock with fractures 10 to 15 centimeters apart; few coarse roots in fractures.
TYPE LOCATION: San Bernardino County, California; approximately 4.1 kilometers west of the junction of Highway 62 and Coxcomb Adit Trail; 67 meters (220 feet) south and 564 meters (1,850 feet) west of the NE corner of section 12, T. 1 S., R. 14 E., San Bernardino Base and Meridian; 34 degrees, 6 minutes and 22.7 seconds north latitude, and 115 degrees, 27 minutes and 44.3 seconds west longitude; USGS Cadiz Valley SW 7.5 minute topographic quadrangle; UTM 11S 0641833e 3775009n (DTM: NAD83).
RANGE IN CHARACTERISTICS:
Soil moisture control section: usually dry, moist in some parts for short
periods during winter and early spring and for 10 to 20 days cumulative
between July and September following convection storms. The soils have a
typic-aridic soil moisture regime.
Soil temperature: 22 to 25 degrees C (72 to 77 F).
Surface rock fragments: 55 to 80 percent; with 10 to 30 percent fine gravel,
35 to 55 percent medium and coarse gravel, 1 to 10 percent cobbles, 0 to
10 percent stones and 0 to 1 percent boulders.
Control section -
Depth to a lithic contact: 3 to 18 centimeters (1 to 7 inches).
Rock fragments: 15 to 30 percent; gravel and cobbles.
Clay content: 2 to 6 percent.
Organic matter: 0 to 0.25 percent.
A horizon
Hue: 10YR or 2.5Y.
Value: 5 to 7 dry, 4 or 5 moist.
Chroma: 3 or 4 dry, 2 or 3 moist.
Clay content: 3 to 6 percent.
Rock fragments: 10 to 25 percent gravel.
Effervescence: noneffervescent to violently effervescent.
Calcium carbonate equivalent: 0 to 1 percent.
Reaction: neutral to moderately alkaline.
C horizon (when present)
Hue: 10YR or 2.5Y.
Value: 5 to 7 dry, 5 or 6 moist.
Chroma: 3 or 4, dry.
Texture of the fine earth: sand or loamy sand.
Clay content: 2 to 4 percent.
Rock fragments: 20 to 30 percent; with 20 to 30 percent gravel and 0 to 5
percent cobbles.
Effervescence: noneffervescent to violently effervescent.
Calcium carbonate equivalent: 0 to 1 percent.
Reaction: neutral to moderately alkaline.
COMPETING SERIES: There are no competing series at this time.
GEOGRAPHIC SETTING: Impedimenta soils are on pediments, hills and mountain backslopes. Slopes range from 4 to 60 percent. These soils formed in dominantly granitoid residuum. Elevations range from 510 to 840 meters (1,673 to 2,755 feet). The climate is arid, with hot, dry summers and warm, moist winters. The mean annual precipitation is 75 to 125 millimeters (3 to 5 inches) and the mean annual air temperature is 20 to 23 degrees C (68 to 73.5 degrees F). The frost-free season is 300 to 340 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Blackeagle and
Marbolite soils on similar landscape positions,
Dalelake soils on sandsheets adjacent to or partially covering lower mountain slopes and pediments, and
Pintobasin soils on adjacent fan aprons and drainageways. Blackeagle soils are characterized by a cambic horizon, have a loamy-skeletal particle-size control section and have a lithic contact between 36 and 50 centimeters. Marbolite soils have an argillic horizon. Dalelake and Pintobasin soils are very deep and are formed in eolian and alluvial materials, respectively.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained; medium to high runoff; high saturated hydraulic conductivity above the bedrock and low saturated hydraulic conductivity within the bedrock.
USE AND VEGETATION: Impedimenta soils are used for recreation and wildlife habitat. The present vegetation is mainly Mojave indigobush, water jacket, creosote bush, and burrobush.
DISTRIBUTION AND EXTENT: Southern Mojave Desert of southeastern California. MLRA 30. These soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA
SERIES ESTABLISHED: San Bernardino County, California, Joshua Tree National Park Soil Survey, 2012. The name is coined.
REMARKS: Diagnostic horizons and features in this pedon include:
Ochric epipedon - from a depth of 0 to 2 centimeters (A horizon).
Lithic contact - the zone beginning at 10 centimeters (R horizon).
Particle-size control section - from a depth of 0 to 10 centimeters (A and C
horizons).
ADDITIONAL DATA: NASIS Pedon User ID: 12483045-T.
Responsibility for this series was transferred from Davis to Phoenix 4/2015. The last revision to the series was 5/2012. ET
National Cooperative Soil Survey
U.S.A.