LOCATION ULHALF CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, isotic, mesic Vitrandic Haploxeralfs
TYPICAL PEDON: Ulhalf very gravelly sandy loam, forested, on a 9 percent SSE facing slope under Jeffery pine, ponderosa pine and incense-cedar at 5,040 feet elevation. (When described, September 23, 1985, the soil was dry throughout. Colors are for dry soil unless otherwise noted).
Oi--2 inches to 0; fresh and decomposed litter of needles, twigs and cones; abrupt wavy boundary.
A--0 to 4 inches; reddish brown (5YR 5/3) very gravelly sandy loam, dark reddish brown (5YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine interstitial pores; 10 percent cobbles, 15 percent 5 to 75 mm pebbles and 10 percent 2 to 5 mm pebbles; slightly acid (pH 6.5); clear wavy boundary. (2 to 4 inches thick)
BA--4 to 13 inches; reddish brown (5YR 5/4) gravelly loam, dark reddish brown (5YR 3/4) moist; moderate medium and coarse subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; few very fine, common fine and medium roots; few very fine interstitial and tubular and few fine tubular pores; 10 percent cobbles, 10 percent 5 to 75 mm pebbles and 10 percent 2 to 5 mm pebbles; slightly acid (pH 6.5); clear wavy boundary. (4 to 9 inches thick)
Bt1--13 to 18 inches; light reddish brown (5YR 6/4) gravelly loam, reddish brown (5YR 4/4) moist; strong medium and coarse subangular blocky structure; very hard, very friable, sticky and plastic; friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine interstitial pores; few thin clay films on peds; 10 percent cobbles, 10 percent 5 to 75 mm pebbles and 10 percent 2 to 5 mm pebbles; slightly acid (pH 6.5); clear wavy boundary.
Bt2--18 to 37 inches; reddish yellow (5YR 6/6) gravelly clay loam, yellowish red (5YR 4/6) moist; strong medium and coarse subangular blocky structure; very hard, friable, sticky and plastic; few fine and medium roots; common very fine tubular pores; many moderately thick clay films on peds and in pores; 15 percent 5 to 75 mm pebbles and 15 percent 2 to 5 mm pebbles; slightly acid (pH 6.5); gradual wavy boundary.
Bt3--37 to 54 inches; reddish yellow (5YR 6/6) gravelly clay loam, yellowish red (5YR 4/6) moist; strong medium and coarse subangular blocky structure; very hard, friable, sticky and plastic; few fine and medium roots; common very fine tubular pores; many moderately thick clay films on peds and in pores; 15 percent 5 to 75 mm pebbles and 15 percent 2 to 5 mm pebbles; slightly acid (pH 6.5); abrupt wavy boundary. (The combined thickness fo the Bt horizons is 34 to 56 inches)
Crt--54 inches; soft massive andesite; clay films in most vesicles; easily dug with spade.
TYPE LOCATION: Lassen County, California; located about 4 miles W of Susanville; about 1.0 mile N of Piaute Creek on the Paul Bunyan Logging Road and 300 feet N of the road; 2,400 feet W and 650 feet N of the SE corner of section 22, T.30 N., R.11 E.
RANGE IN CHARACTERISTICS: Thickness of solum and depth to the paralithic contact ranges from 40 to 60 inches. The mean annual soil temperature varies from 47 to 50 degrees F. The soil moisture control section (10 to 26 inches) is dry from July 15 to November 1 (107 days) and is moist in all parts from December 1 to May 15. The soil temperature exceeds 41 degrees from April 15 to December 1 and exceeds 47 degrees F from May 15 to November 15. Base saturation ranges from 50 to 75 percent. Rock fragments on the surface range from 10 to 15 percent cobbles and 10 to 40 percent gravel.
The A horizon is 5YR 5/3 or 7.5YR 5/4. Moist color is 5YR 3/3 or 7.5YR 3/4. It is loam or sandy loam modified by 15 to 50 percent gravel.
The BA and Bt1 horizons dry colors are 5YR 5/4 or 6/4. Moist colors are 5YR 3/4 or 4/4. It is gravelly loam or very gravelly loam with 20 to 25 percent clay and 20 to 40 percent gravel. Reaction is slightly or medium acid.
The Bt2 and Bt3 horizons dry colors are 5YR 5/6, 6/4 or 6/6. Moist colors are 5YR 3/4, 4/4 or 4/6. It is gravelly loam or gravelly clay loam with 25 to 35 percent clay and 20 to 35 percent gravel. Reaction is slightly or medium acid.
COMPETING SERIES: These are the Bernhill, Boomer, Casabonne, Centralia, Cherryhill, Cle Elum, Cohasset, Crozier, Fives, Holland, Hood, Hotaw, Kalama, Latourell, Musick, Sanhedrin, Speaker, Underwood, Varelum, Wilkeson and Wohly series. Bernhill soils are dry 60 to 80 days, have C horizons and have a hue of 10YR. Cle Elum, Crozier, Hotaw, Speaker and Wohly soils have bedrock within 40 inches. Boomer, Casabonne, Cherryhill, Cohasset, Holland, Hotaw, Latourell and Musick soils have a mean annual soil temperature greater than 52 degrees F. Centralia, Fives, Hood, Kalama, Underwood, Verelum and Wilkeson soils are dry less than 90 consecutive days. Sanhedrin soils have a mean annual soil temperature of 50 to 58 degrees F and a base saturation in the Bt horizon of 35 to 55 percent.
GEOGRAPHIC SETTING: Ulhalf soils are on plateaus and mountain back slopes. These soils formed in material weathered from basalt or andesite or metavolcanic rock. Slopes are 2 to 50 percent. Elevation ranges from 4,400 and 5,400 feet. The climate is subhumid with warm dry summers and cold moist winters. The mean annual precipitation is about 20 to 40 inches with 40 to 70 inches of snow. The mean annual temperature is about 48 degrees F the mean July temperature is about 66 degrees F, and the mean January temperature is about 26 degrees F. The frost-free season is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Southpac and Gavel soils. Both soils are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; runoff is slow to medium; moderately slow permeability.
USE AND VEGETATION: Ulhalf soils are used for timber production. Vegetation is Jeffery pine, ponderosa pine, incense-cedar, antelope bitterbrush and squawcarpet. Moist phases have white fir, Douglas fir, ponderosa pine, sugar pine and incense cedar.
DISTRIBUTION AND EXTENT: Lassen County, CA, near Susanville. The soils of this series are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Lassen County, California; Susanville Area, Parts of Lassen and Plumas Counties, Soil Survey Area, 1988.
REMARKS: Diagnostic horizons and features recognized in the pedon are:
Ochric epipedon - The zone from the mineral soil surface to a depth of 4 inches. (A horizon)
Argillic horizon - the zone from about 13 to 54 inches. (Bt1, Bt2, Bt3 horizons)
Paralithic contact - the zone from 54 to 60 inches. (Crt horizon)