LOCATION TUNEHILL CAEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, thermic, shallow Typic Haploxerolls
TYPICAL PEDON: Tunehill loam - on a southeast facing slope of 40 percent under soft chess, wild oats, red brome, filaree, tarweed, and other grasses and forbs at an elevation of 1,360 feet. (Colors are for dry soil unless otherwise stated. When described on October 5, 1981, the soil was dry throughout.)
A--0 to 7 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; common fine and medium angular blocky and platy structure; slightly hard, friable, sticky and plastic; common very fine roots; few very fine tubular pores; organic matter is 3.2 percent; slightly alkaline (pH 7.8); clear smooth boundary. (5 to 9 inches thick)
Bw--7 to 11 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; common fine and medium angular blocky structure; slightly hard, friable, sticky and plastic; common very fine roots; common very fine tubular pores; 5 percent soft, angular, consolidated sediments 2 to 5 mm in size; organic matter is 0.9 percent; slightly alkaline (pH 7.8); abrupt irregular boundary. (3 to 6 inches thick)
Cr--11 to 60 inches; white (10YR 8/2) soft, consolidated volcanic sediments, pale brown (10YR 6/3) moist.
TYPE LOCATION: Merced County, California about 18 miles southwest of the city of Los Banos, 2,600 feet south and 1,400 feet west of the NE corner of Section 16, T. 12 S., R. 8 E., projected section lines from Section 18, T. 12 S., R. 9 E., Los Banos Valley Quadrangle:
RANGE IN CHARACTERISTICS: Depth to a paralithic contact ranges from 10 to 15 inches. The mean annual soil temperature is 59 degrees to 64 degrees F. The soil temperature is below 47 degrees F in parts of January and February. The soil between a depth of 8 inches and the paralithic contact is moist throughout from November 15 to May 15 and dry throughout from June 15 to October 15 most years. In some pedons the mollic epipedon extends into the Bw horizon to the paralithic contact.
The A horizon is 10YR 4/2, 5/1, 5/2, 5/3; or 2.5Y 5/2. Moist colors are 10YR 3/2, 3/3; or 2.5Y 3/2. Clay content ranges from 15 to 25 percent. Organic matter content ranges from 1 to 4 percent. Reaction is neutral to moderately alkaline.
The Bw horizon is 10YR 5/3, 5/4, 6/3, or 6/4. Moist colors are 10YR 3/3, 4/2, 4/3, 4/4, or 5/4. It is loam or silt loam with 18 to 27 percent clay content. Reaction is slightly alkaline or moderately alkaline.
The consolidated volcanic sediments are stratified as to type of material and degree of hardness. They are gravelly in some pedons.
COMPETING SERIES: This is the Tunis series in the same family and the Bonnydoon, Calodo, Caperton, Friant, Illito, and Lodo series in other families. Tunis soils have less than 18 percent clay content in the texture control section and are somewhat excessively drained. Bonnydoon and Caperton soils do not have a Bw horizon. Calodo soils are calcareous. Friant and Lodo soils have a lithic contact. Illito soils have an argillic horizon.
GEOGRAPHIC SETTING: Tunehill soils are on hillslopes of high elevation dissected terraces and have slopes of 30 to 50 percent. Elevations range from 1,200 to 1,500 feet. These soils formed in mixed consolidated alluvium of the Peckham Formation derived dominantly from basic igneous rock of the Quien Sabe Formation. The climate is subhumid with hot dry summers and cool moist winters. Mean annual precipitation is 15 to 20 inches. The mean January temperature is about 44 degrees F; mean July temperature is about 72 degrees F; and mean annual temperature is about 61 degrees F. Frost-free season is 200 to 230 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Orognen and Quiensabe soils. Orognen soils are over 60 inches deep and have a fine-textured argillic horizon. Quiensable soils have a lithic contact between a depth of 20 and 40 inches and a fine-textured argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff, moderate permeability.
USE AND VEGETATION: These soils are used as rangeland and upland wildlife habitat. The vegetation is soft chess, filaree, red brome, foxtail fescue, wild oats, tarweed, vinegar weed, and other grasses and forbs.
DISTRIBUTION AND EXTENT: Tunehill soils are on high elevation terraces in intermountain valleys of the Central California Coast Range. They are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Merced County, California 1984. Name is coined.
REMARKS: These soils were mapped as Keefers in the Los Banos Area, series 1939 report. They are being differentiated by not having the clayey-skeletal texture control section and by not being greater than 60 inches deep as is typical of the Keefers series. pH determined by colorimetric method using Thymol Blue and Hellige-Troug Triplex indicators. Texture determined by modified Bouyoucos method. Organic matter determined by Walkley-Black digestion method.
The activity class was added to the classification in March of 2003. Competing series were not checked at that time. - ET