LOCATION LUDI                    OR

Established Series
Rev. RPM-MPK-JVC-JBF
04/2011

LUDI SERIES

The Ludi series consists of very deep, somewhat excessively drained soils that formed in eolian material derived from volcanic ash and colluvium derived from basalt over basaltic cinders. Ludi soils are on cinder cones. Slopes are 15 to 65 percent. The mean annual precipitation is about 360 mm and the mean annual temperature is about 6 degrees C.

TAXONOMIC CLASS: Ashy-skeletal over fragmental or cindery, glassy over mixed, frigid Vitrandic Haploxerolls

TYPICAL PEDON: Ludi very gravelly ashy loam--on a 50 percent south-facing slope of a cinder cone at 1,770 meters elevation--rangeland. (Colors are for dry soil unless otherwise noted. When described on June 25, 1996 the soil was dry throughout.)

A1--0 to 13 cm; grayish brown (10YR 5/2) very gravelly ashy loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine interstitial pores; 40 percent gravel; neutral (pH 6.8); clear smooth boundary. (8 to 20 cm thick)

A2--13 to 48 cm; brown (10YR 5/3) very gravelly ashy loam, very dark grayish brown (10YR 3/2) moist; weak very fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and few fine roots; many very fine interstitial pores; 40 percent gravel; neutral (pH 7.0); gradual smooth boundary. (23 to 43 cm thick)

Bw--48 to 91 cm; yellowish brown (10YR 5/4) very gravelly ashy sandy loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many fine interstitial pores; 50 percent gravel; neutral (pH 7.0); clear smooth boundary. (25 to 58 cm thick)

2C--91 to 152 cm; dark reddish brown (5YR 3/4) fragmental material, dark reddish brown (5YR 3/4) moist; few very fine roots in upper part; many fine through coarse interstitial pores; about 95 percent gravel-size basaltic cinders 3 to 8 cm in diameter; neutral (pH 7.0).

TYPE LOCATION: Lake County, Oregon; on the Deschutes National Forest on the southwest side of Fox Butte; approximately 1,400 feet east and 2,200 feet north of the southwest corner of section 6, T. 23 S., R. 16 E.; USGS Fox Butte 7.5 minute topographic quadrangle; latitude 43 degrees 36 minutes 26 seconds N and longitude 120 degrees 50 minutes 53 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist, but are dry in all parts of the soil moisture control section for 45 or more consecutive days within the four months that follow the summer solstice; xeric moisture regime that borders on aridic.
Mean annual soil temperature: 7 to 8 degrees C.
Mollic epipedon thickness: 18 to 53 cm.
Depth to base of cambic horizon: 50 to 100 cm.
Depth to strongly contrasting cindery material: 50 to 100 cm.

Particle-size control section - Clay content: 8 to 18 percent in the upper part and 0 to 2 percent in the strongly contrasting lower part
Rock fragments: 35 to 80 percent in the upper part and 90 to 100 percent in the strongly contrasting lower part. Lithology of fragments is basalt in the upper part and basaltic cinders in the lower part.

A1 horizon
Value: 4 and 5 dry.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 to 4 percent.
Volcanic glass content: 30 to 60 percent in coarse silt through fine sand fractions.

A2 horizon
Value: 4 and 5 dry.
Chroma: 2 or 3, dry or moist.
Texture: Very gravelly ashy very fine sandy loam, very gravelly ashy loam, very gravelly ashy sandy loam, or extremely gravelly ashy sandy loam.
Organic matter content: 1 to 3 percent.
Volcanic glass content: 30 to 60 percent in coarse silt through fine sand fractions.

Bw horizon
Value: 5 or 6 dry, 3 or 4 moist.
Chroma: 3 or 4, dry or moist.
Texture: Very cobbly ashy very fine sandy loam, extremely cobbly ashy very fine sandy loam, very gravelly ashy sandy loam, or extremely gravelly ashy sandy loam.
Organic matter content: 0.5 to 1 percent.
Volcanic glass content: 30 to 60 percent in coarse silt through fine sand fractions.

2C horizon
Value: 3 through 5 dry.
Chroma: 2 through 4, dry or moist.
Rock fragments: 90 to 100 percent gravel-size basaltic cinders.

COMPETING SERIES: There are currently no other series in this family.

GEOGRAPHIC SETTING: Ludi soils are on cinder cones. They typically occur on backslope positions. These soils formed in eolian material derived from volcanic ash and colluvium derived from basalt over basaltic cinders. The source of the volcanic ash is ancestral Mt. Mazama. Slopes are 15 to 65 percent. Elevations range from 1,345 to 1,830 meters. The climate is semiarid and characterized by cold, moist winters and warm, dry summers. The mean annual precipitation dominantly is 300 to 460 mm but in some areas may range from 250 mm. The mean annual temperature is 6 to 7 degrees C. The frost-free period is 40 to 80 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bluesters, Glencabin, Henkle, and Wanoga soils. Bluesters soils are ashy over pumiceous or cindery, have andic soil properties, and are on more moist areas of cinder cones. Glencabin soils are ashy-skeletal, moderately deep to lithic contacts, and are on adjacent buttes and hills. Henkle soils are ashy-skeletal, shallow to lithic contacts, have andic soil properties, and occur on adjacent hills and plateaus. Wanoga soils are ashy, moderately deep to paralithic contacts, have andic soil properties, and occur on adjacent hills and plateaus.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat excessively drained; medium surface runoff; moderately rapid permeability; high saturated hydraulic conductivity in the upper part over very rapid permeability; very high saturated hydraulic conductivity in the strongly contrasting lower part.

USE AND VEGETATION: Ludi soils are used for livestock grazing and wildlife habitat. The vegetation is mainly western juniper, mountain big sagebrush, antelope bitterbrush, Idaho fescue, and bluebunch wheatgrass. Some areas have open stands of ponderosa pine.

DISTRIBUTION AND EXTENT: South-central Oregon. These soils are not extensive with about 4,500 acres of the series mapped to date. MLRA 23.

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

SERIES ESTABLISHED: Lake County (Northern Part), Oregon, 2006.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 48 cm (A1 and A2 horizons).
Cambic horizon - The zone from 48 to 91 cm (Bw horizon).
Vitrandic intergrade feature - The zone from the soil surface to 91 cm (A1, A2, and Bw horizons).
Major lithologic discontinuity - The change to cindery material at 91 cm (2C horizon).
Particle-size control section - The zone from 25 to 100 cm (Bw horizon and parts of the A2 and 2C horizons).

---

National Cooperative Soil Survey
U.S.A.