LOCATION LUD ID

Established Series
Rev. DL/DA/CLM
06/2019

LUD SERIES

The Lud series consists of soils that are well drained and shallow to a duripan that formed in alluvium from mixed sources. They are on terraces. Permeability is slow. Slopes range from 2 to 10 percent. The average annual precipitation is about 250 mm, and the average annual temperature is about 7.8 degrees C.

TAXONOMIC CLASS: Clayey, smectitic, mesic, shallow Xeric Argidurids

TYPICAL PEDON: Lud silt loam--on a 3 percent slope under rangeland vegetation at 1,630 meter elevation. When described on June 10, 1982, the soil was slightly moist throughout. (Colors are for dry soil unless otherwise stated.)

A--0 to 5 cm; pale brown (10YR 6/3) silt loam, dark brown (10YR 3/3) moist; moderate medium platy structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine tubular pores; 5 percent gravel and 5 percent cobbles; neutral (pH 6.6); clear smooth boundary. (5 to 10 cm thick)

Bt1--5 to 20 cm; pale brown (10YR 6/3) silty clay loam, brown (10YR 4/3) moist; weak fine angular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine and fine roots; many very fine tubular pores; few faint clay films on faces of peds and in pores; neutral (pH 7.2); clear smooth boundary. (8 to 15 cm thick)

Bt2--20 to 28 cm; pale brown (10YR 6/3) silty clay loam, brown (10YR 4/3) moist; strong medium angular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine roots; common very fine tubular pores; many distinct clay films on faces of peds and in pores; strongly effervescent (4 percent calcium carbonate); slightly alkaline (pH 7.6); clear smooth boundary. (8 to 25 cm thick)

Bkq--28 to 41 cm; very pale brown (10YR 7/3) gravelly loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; very hard, very firm, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; 20 percent gravel; violently effervescent (32 percent calcium carbonate); slightly alkaline (pH 7.8); abrupt smooth boundary. (5 to 18 cm thick)

Bkqm--41 to 66 cm; white (10YR 8/1) fractured duripan, very pale brown (10YR 7/3) moist; massive; indurated; extremely hard, extremely firm; many 3 to 25 cm thick carbonate-silica cemented lenses; few very fine roots in fractures of the duripan; fractures are 6 mm wide and 23 cm apart; violently effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (8 to 51 cm thick)

2R--66 cm; dark gray (10YR 4/1) fractured basalt, black (10YR 2/1) moist; carbonate coated; violently effervescent.

TYPE LOCATION: Twin Falls County, Idaho; about 13 miles west of Rogerson, Idaho, about 2,300 feet east and 360 feet south of the northwest corner section 17, T. 14 S., R. 14 E; USGS Browns Bench North 7.5 minute topographic quadrangle; latitude 42 degrees 12 minutes 53 seconds N and longitude 114 degrees 50 minutes 31 seconds W; WGS84 Decimal Degrees 42.2147222 latitude, -114.8419444longitude.

RANGE IN CHARACTERISTICS:
Depth to the duripan - 25 to 50 cm.
Depth to bedrock - 53 to 100 cm.
Average clay content in the control section - 35 to 45 percent Average annual soil temperature - 8.3 to 9.4 degrees C.
Soil moisture: Usually dry, moist in the winter and spring, dry from late June through October; aridic soil moisture regime bordering on xeric.

A horizon
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 2 or 3 dry or moist

Bt horizon
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Subangular blocky or angular blocky structure
Textures - SICL, SIC, CB-SICL, CB-SIC
Gravel - 0 to 10 percent
Cobbles - 0 to 10 percent
Reaction - neutral or mildly alkaline

Bkqm horizon
Thickness of laminar caps - 3 to 38 mm.
Structure - massive or platy
Cementation below laminar caps - weak through very strong
Width of fractures - 3 to 12 mm.
Distance between fractures - 20 to 50 mm.
Thickness of duripan - 8 to 50 mm.
Thickness of subsequent laminations - 3 to 25 mm

COMPETING SERIES: These are the Buffaran, Indian Creek, Midraw, and Norfork series. Buffaran and Indian Creek soils are greater than 150 cm deep to bedrock. Midraw soils have gravelly clay loam or gravelly clay textures in the Bt horizon. Norfork soils have 20 to 30 percent coarse fragments in the control section.

GEOGRAPHIC SETTING: Lud soils are on terraces. The slope ranges from 2 to 10 percent. The soils formed in alluvium from mixed sources. Elevations are 1,375 to 1,620 meters. The average annual precipitation ranges from 230 to 280 mm. The average annual temperature is 7.2 to8.3 degrees C. The frost free season is 100 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arness, Chuska, and Owsel soils. Arness and Chuska soils occur on lower terraces, and are loamy. Owsel soils occur on terrace sideslopes, and are very deep.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; slow runoff; slow saturated hydraulic conductivity.

USE AND VEGETATION: Lud soils are used for rangeland. Native vegetation is Wyoming big sagebrush, bluebunch wheatgrass, and Sandberg bluegrass.

DISTRIBUTION AND EXTENT: Lud soils are of moderate extent in south central Idaho. MLRA 25.

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

SERIES ESTABLISHED: Twin Falls County, Idaho, 1992.

REMARKS: Clay percent by hydrometer: 0 to 5 cm - 22 percent; 5 to 20 cm - 37 percent; 20 to 28 cm - 35 percent; 28 to 41 cm - 30 percent.

Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 5 cm (A horizon).
Argillic horizon - the zone from 5 to 28 cm (Bt1 and Bt2 horizons).
Calcic horizon - the zone from 28 to 66 cm (Bkq and Bkqm horizons).
Duripan - the zone from 41 to 66 cm (Bkqm horizon).
Lithic contact - 66 cm.

National Cooperative Soil Survey
U.S.A.