LOCATION PENTZ CA

Established Series
Rev. AJT-WBS-MAM-CEJ-AJP-JTW
12/2018

PENTZ SERIES

The Pentz series consists of shallow, well drained soils that formed in colluvium or residuum derived from basic tuff. Pentz soils are on hills with mound and swale microrelief, and on backslopes of hills. These soils are on the mound position. Slopes are 2 to 60 percent. The mean annual precipitation is about 440 mm and the mean annual air temperature is about 17 degrees C.

TAXONOMIC CLASS: Loamy, mixed, superactive, thermic, shallow Ultic Haploxerolls

TYPICAL PEDON: Pentz fine sandy loam on an east-facing, 5 percent, convex, complex slope on a mound, under soft chess, filaree and medusahead at an elevation of 75 meters. (Colors are for dry soil unless otherwise stated. When described on September 29, 1982, the soil was moist throughout.)

A1--0 to 10 cm; brown (10YR 5/3) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; many very fine, common fine roots; many very fine and few fine interstitial and common very fine tubular pores; 5 percent rounded and subrounded gravel; moderately acid (pH 6.0); clear smooth boundary. (8 to 15 cm thick)

A2--10 to 23 cm; brown (10YR 5/3) fine sandy loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; many very fine roots, common very fine and few fine tubular and many very fine interstitial pores; 5 percent rounded and subrounded gravel, moderately acid (pH 6.0); clear smooth boundary. (10 to 23 cm thick)

Bw--23 to 32 cm; brown (10YR 5/3) fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine roots; many medium and common very fine tubular and many very fine interstitial pores; few thin clay films bridging mineral grains; 5 percent rounded and subrounded gravel; slightly acid (pH 6.5); clear smooth boundary. (5 to 30 cm thick)

Bt--32 to 41 cm; brown (10YR 5/3) fine sandy loam, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure; hard, friable, slightly sticky, slightly plastic; few very fine roots; many medium and common very fine tubular pores and many fine interstitial pores; few thin clay films on ped faces bridging mineral grains and lining pores; 5 percent rounded and subrounded gravel; slightly acid (pH 6.5); abrupt wavy boundary. (0 to 8 cm thick)

Cr--41 to 58 cm; variegated pale yellow (2.5Y 7/4) very dark grayish brown (2.5Y 3/2) and grayish brown (2.5Y 5/2) weakly consolidated basic tuff, olive brown (2.5Y 4/4), very dark grayish brown (2.5Y 3/2) and light olive brown (2.5Y 5/4) moist; slightly acid (pH 6.5).

TYPE LOCATION : Sacramento County, California; about 4.8 km (3 mi) south of Bridge House, 3.7 km (2.3 mi) west of Meiss Road and Ione Road intersection, about 69 meters (225 feet) east of north-south fence, 98 meters (320 feet) north of Meiss Road, and 1,550 feet south and 2,435 feet west of the northeast corner of sec. 22, T. 7N., R. 8E., MDB&M. USGS 7.5 minute topographic quadrangle: Carbondale, California; WGS84 38.4483337 latitude -121.0841675 longitude. UTM Zone 10 667189 E 4257299 N NAD83.

RANGE IN CHARACTERISTICS:
Soil temperature: The mean annual soil temperature varies from 18 to 19 degrees C and the temperature remains above 8 degrees C throughout the year.

Soil moisture: The soil moisture control section is dry in all parts from about May to October (about 150 days). The soils have a xeric moisture regime.

Diagnostic feature(s):
Mollic epipedon thickness: 18 to 50 cm
Cambic horizon thickness: 15 to 20 cm (when present)
Depth to paralithic contact: 20 to 50 cm

Particle size control section weighted average:
Clay content: 10 to 20 percent
Rock fragments: 0 to 35 percent
0 to 25 percent cobbles or stones

Organic matter: in the upper 18 cm mixed is 1 to 3 percent.

Base saturation (by sum of cations): 60 to 75 percent in the A horizon and greater than 75 percent below this depth.

A horizons (A1 and A2)
Hue: 10YR dry; 10YR, 7.5YR moist
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3
Texture: sandy loam, fine sandy loam, silt loam, or loam
Clay content: 8 to 18
Reaction: slightly to strongly acid

Bw horizon
Hue: 10YR, 7.5YR
Value: 4 to 6 dry; 2 to 5 moist
Chroma: 2 to 4
Texture: sandy loam, fine sandy loam, silt loam, or loam
Clay content: 10 to 20 percent and 1 to 3 percent more than the A horizon
Reaction: moderately acid to neutral
Organic matter: less than 1 percent

Bt horizon (when present)
Hue: 10YR, 7.5YR
Value: 4 to 6 dry; 2 to 5 moist
Chroma: 2 to 4
Texture: sandy loam, fine sandy loam, silt loam, loam, or sandy clay loam
Clay content: 12 to 22 percent with 3 percent more than the A horizon
Reaction: moderately acid to neutral
Organic matter: less than 1 percent

The Cr horizon is commonly the color of individual sand grains. Dominant hue is 10YR or 2.5Y or it is N 6/0 or 5/0. It is weakly to moderately consolidated.

COMPETING SERIES: There are no other soils in this family.

GEOGRAPHIC SETTING: Pentz soils are on mound positions on hillslopes with mound and swalemicrorelief. The microrelief is most strongly expressed on slopes of less than 20 percent. Pentz soils are also found on steep backslope positions on hillslopes and lahars. Slopes are convex or linear and are 2 to 60 percent. Elevation is 30 to 660 meters. The soils formed in colluvium or residuum derived from basic tuff (andesitic) primarily associated with the Mehrten formation. The grain size distribution of these volcaniclastic rocks is dominantly sand sized, but there can layers with conglomerate or andesitic coarse fragments in some areas. More strongly consolidated strata may outcrop as bands across a hill slope. Coarse fragments in the soil are commonly a lag deposit from remnant Pleistocene stream terraces associated with the overlying Arroyo Seco or China Hat formations. The climate is Mediterranean with hot, dry summers and cool, moist winters. Mean annual precipitation is 350 to 870 mm. Mean annual temperature is 15 to 17 degrees C; average January temperature is about 8 degrees C; and average July temperature is about 25 to 27 degrees C. Frost-free period is 235 to 350 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Amador, Gillender, Hadselville , Jennylind, Keyes, Ospital, Pardee, Peters, and Redding soils. Amador and Gillender soils are on hills with mound and swale microrelief, form in acidic tuff, and have dry color values of 6 or more. Hadselville soils are in swales between mounds, are less than 25 cm to a paralithic contact, and lack a cambic horizon. Jennylind and Ospital soils are on erosion remnants and have a lithic contact within 50 cm. Keyes soils are on fans, stream terraces and hills, have an argillic horizon, and a duripan within 50 cm. Pardee soils are on dissected fan remnants, have an argillic horizon, and have greater than 35 percent fragments in the particle-size control section. Peters are on swale positions on hills with mound and swale topograph and have greater than 35 percent clay in the particle-size control section. Redding soils are on dissected fan remnants, have an argillic horizon, and a duripan between 50 to 100 cm.

DRAINAGE AND PERMEABILITY: Well drained; high saturated hydraulic conductivity throughout. Saturated hydraulic conductivity of the bedrock is moderately high.

USE AND VEGETATION: Used mainly for rangeland. Vegetation is soft chess, ripgut brome, filaree, and other annual grasses and forbs.

DISTRIBUTION AND EXTENT: Sierra Nevada Foothills of California; MLRA 18. The series is moderately extensive.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Chico Area, Butte County, California, 1925. Source of name is an unincorporated community in Butte County, CA.

REMARKS: The Pentz series was formerly classified as medial, thermic, shallow Typic Vitrandepts. Although these soils are formed in material that is weathered from tuffaceous sediments, the ash influence is very minor. The type location was moved from Merced County to Sacramento County, California. Pentz clay (adobe) as mapped in the Chico and Lodi Areas, California, conforms to the subsequently established Peters series. Soils mapped as Pentz in Shasta County Area and those mapped on slopes of greater than 50 percent in Eastern Stanislaus County Area need further study to determine if the contact is lithic or paralithic. In addition, those mapped in Shasta County Area are underlain by tuff and may have a stronger ash influence. Some or all of the soils mapped as Pentz in the Amador Area, California are formed in material weathered from acidic tuff and would not be identified as the Pentz series today.

Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 0 to 23 cm (A1 and A2 horizon)
Cambic horizon: 23 to 41 cm (Bw and Bt horizon)
Paralithic contact: 39 cm (Cr horizon)
Particle Size Control Section for this pedon: 25 to 39 cm.

ADDITIONAL DATA:
NASIS User Pedon ID: 82CA067006
Pedon Purpose: Laboratory sampling site
Lab Pedon #: 83P0296
Lab Source ID: SSL

Soil classified using the 12th Edition of the Keys to Soil Taxonomy.

National Cooperative Soil Survey
U.S.A.