LOCATION MILLRACE CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic Pachic Haploxerolls
TYPICAL PEDON: Millrace gravelly fine sandy-loam. (Colors for dry soil unless otherwise stated)
A11--0 to 6 inches; dark brown (10YR 3/3) gravelly fine sandy loam, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure; slightly hard, friable; many very fine roots; many very fine pores; neutral; clear wavy boundary. (3 to 8 inches thick)
A12--6 to 22 inches; brown (10YR 4/3) cobbly very gravelly coarse sandy loam, dark brown (10YR 3/3) moist; moderate medium and subangular blocky structure; slightly hard, friable; common very fine roots; many very fine pores; neutral; clear, wavy boundary. (10 to 25 inches thick).
B2--22 to 42 inches; brown (7.5YR 4/3) very gravelly loamy sand, dark brown (7.5YR 3/3) moist; massive; slightly hard, friable, slightly sticky; few very fine roots; many very fine and medium interstitial pores; sands, gravels, and cobbles are held in place by clay bridges and have thin, nearly continuous clay films on their surfaces; cobbles, gravels, and sands are composed of water worked basalt and andesite; neutral; diffuse, smooth lower boundary. (15 to 20 inches thick).
B3--42 to 60 inches; brown (10YR 4/3) cobbly, very gravelly loamy sand, dark brown (10YR 3/3) moist; massive; slightly hard, friable, slightly sticky; few very fine roots; many very fine and medium interstitial pores; amount of colloid in bridges and thickness and continuity of clay films decreases with increasing depth; neutral. (10 to 15 inches to loose sands and gravels).
TYPE LOCATION: Tehama County, California along the north side of Dye Creek west of Shasta Blvd. in the NE 1/4 of the NE 1/4 of section 1; T26N, R2W.
RANGE IN CHARACTERISTICS: Solum thickness is about 38 to 68 inches and the entire soil is gravelly or cobbly or both. Soil temperature is 63 to 67 degrees F. The soils are dry above the 36 inch depth more than 60 consecutive days during most summers. The A horizons have colors in the 10YR hue with values of 3 to 5 and chromas of 2 or 3. Textures are gravelly or very gravelly and cobbly fine sandy loam to coarse sandy loam. Structure is weak to moderate subangular blocky and consistence is slightly hard and friable. Reaction is slightly acid to neutral. The B2 horizon colors are in the 7.5YR hue with values of 3 or 4 and chromas of 3 or 4. The soils are massive and consistence is slightly hard, friable and slightly sticky. Reaction is neutral to mildly alkaline.
COMPETING SERIES: These include the Ben Hur, Calpine, Crouch, Elder, Molinos, Nord, Rancheria, and Visalia series. The Ben Hur soils are medium and acid and have bedrock at 22 inches. The Calpine soils have medium acid light yellowish brown B2 horizons and Crouch soils have yellowish brown sandy loam B2 horizons. The Elder and Molinos soils are nongravelly sandy loams. Nord soils have brown calcareous light loam C horizons and Rancheria soils have strongly acid B2 horizons. Visalia soils are grayish brown, mildly alkaline, fine sandy loams.
SETTING: The Millrace soils occur on nearly level narrow flood plains on alluvium derived mainly from basic rocks. They occur at elevations of 200 to 500 feet, in a subhumid mesothermal climate with mean annual rainfall of 20 to 35 inches, with hot, dry summers and cool, wet winters. Mean annual temperature is about 63 degrees F., average January temperature about 46 degrees F., and average July temperature about 81 degrees F. Frost-free season averages about 270 days.
PRINCIPAL ASSOCIATED SOILS: These are the Keefers soils on higher terraces, the silty clay loam Los Robles soils on low terraces and the Vina soils in alluvial bottoms.
DRAINAGE AND PERMEABILITY: Well drained with moderately rapid permeability and slow runoff.
USE AND VEGETATION: Used for orchards, pasture and hay and for grazing.
DISTRIBUTION AND EXTENT: All streams on the east side of the Sacramento River in Norther California. The soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Tehama County, California 1962.
REMARKS: These soils formerly were classified as Prairie soils.
OSED scanned by SSQA. Last revised by state on 9/68.