LOCATION FRENCHMAN CA

Established Series
Rev. CAR-DJE-JJJ-JWH-KP
07/2016

FRENCHMAN SERIES

The Frenchman series consists of very deep, well drained soils formed in alluvium from mixed sources. Frenchman soils are on stream terraces and have slopes of 0 to 9 percent. The mean annual precipitation is about 1520 centimeters and the mean annual temperature is about 12 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, isomesic Typic Dystrustepts

TYPICAL PEDON: Frenchman very gravelly sandy loam - on a moderately sloping river terrace of 5 percent, under Douglas-fir, tanoak and California huckleberry, at 350 feet elevation. (Colors are for dry soil unless otherwise noted. When described November 4,1981 the soil was moist below 46 inches.)

Oi--0 to 5 centimeters (0 to 2 inches); decomposed and partially decomposed litter of Douglas-fir and tanoak leaves and twigs.

A--5 to 30 centimeters (2 to 12 inches); light yellowish brown (10YR 6/4) very gravelly sandy loam, yellowish brown (10YR 5/4) moist; weak very fine and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine and few medium and coarse roots; many very fine and fine interstitial and few fine tubular pores; 45 percent rounded and subrounded sandstone gravel and 5 percent rounded sandstone cobbles; strongly acid (pH 5.4); clear wavy boundary. (20 to 25 centimeters thick)

Bw1--30 to 68 centimeters (12 to 27 inches); light yellowish brown (10YR 6/4) very gravelly sandy loam, dark yellowish brown (10YR 4/6) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine, fine, medium and coarse roots; many very fine and fine interstitial and few fine tubular pores; 35 percent hard rounded and subrounded sandstone gravel and 10 percent rounded sandstone cobbles; moderately acid (pH 5.6); clear wavy boundary. (25 to 50 centimeters thick)

Bw2--68 to 81 centimeters (27 to 32 inches); light yellowish brown (10YR 6/4) very gravelly sandy loam, dark yellowish brown (10YR 4/6) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine and few medium and coarse roots; common fine interstitial and few very fine tubular pores; 30 percent rounded and subrounded sandstone gravel (2-75 mm) and 10 percent rounded sandstone cobbles (7.5-20 cm); moderately acid (pH 5.6); abrupt wavy boundary. (25 to 50 centimeters thick)

2C1--81 to 112 centimeters (32 to 44 inches); yellowish brown (10YR 5/4) extremely gravelly sand, dark yellowish brown (10YR 4/4) moist; single grain; loose, nonsticky and nonplastic; few very fine and fine roots; many very fine and fine interstitial pores; 50 percent rounded and subrounded sandstone gravel and 20 percent rounded sandstone cobbles; moderately acid (pH 5.6); clear wavy boundary. (25 to 50 centimeters thick)

3C2--112 to 162 centimeters (44 to 64 inches); light yellowish brown (2.5Y 6/4) extremely cobbly loamy sand, dark yellowish brown (10YR 4/4) moist; single grain; loose, nonsticky and nonplastic; few very fine and fine roots; common very fine interstitial pores; 55 percent rounded and subrounded sandstone gravel and 30 percent rounded sandstone cobbles; moderately acid (pH 5.8).

TYPE LOCATION: Mendocino County, California; from Clark Opening, head south through opening, cross Big River, follow logging road about 200 feet to skid trail on right, down skid trail about 120 feet. Site is 20 feet southwest of trail; about 2,400 feet E. and 1,600 feet N. of the SW corner section 2, T.16 N., R.15 W., Comptche Southeast Quadrangle; WGS84 40.0234139 latitude, and -123.7942944 longitude, UTM zone 10 432222.00mE and 4430658mN; NAD83.

RANGE IN CHARACTERISTICS: Total soil depth is greater than 150 centimeters. Thickness of the A horizon ranges from 20 to 25 centimeters. Thickness of the solum ranges from 71 to 114 centimeters. The mean annual soil temperature ranges from 11 to 13 degrees C. The difference between mean summer and mean winter soil temperature varies from 3 to less than 6 degrees C. The soils have an isomesic temperature regime. The soil between the depths of 36 and about 43 centimeters is moist in all parts from November 1 until August 1 and is dry in some part of all parts from September 1 to October 1 in most years. The soils have an ustic temperature regime. The particle-size control section ranges from 5 to 25 percent clay and averages 10 to 18 percent clay. Organic carbon is assumed to decrease regularly with depth.

The A horizon is 10YR 4/2, 4/3, 5/2, 5/4, 5/4, 6/4 or 7.5YR 5/2 or 6/4. Moist color is 10YR 2/2, 3/2, 3/3, 4/3, 4/4, 5/4 or 7.5YR 3/2 or 4/4. It is gravelly loam or very gravelly sandy loam with 10 to 20 percent clay and 15 to 50 percent gravel. Cobble content ranges from 0 to 10 percent. Base saturation (sum) ranges from 15 to 45 percent. Reaction is neutral through strongly acid.

The Bw horizon is 10YR 5/3, 5/4, 6/3, 6/4, 7/3, 7/4 or 7.5YR 6/4. Moist color is 10YR 4/3, 4/4, 4/6, 5/4, 5/6 or 7.5YR 3/4 or 4/4. Textures are very gravelly sandy loam, very gravelly loam or very gravelly sandy clay loam. Clay content ranges from 10 to 25 percent. Gravel content ranges from 35 to 50 percent and cobble content ranges from 5 to 10 percent. Base saturation (sum) ranges from 10 to 40 percent. Reaction is moderately acid through very strongly acid.

The C horizon is 10YR 5/4, 6/3, 6/4, 6/6, 7/3, 7/4 or 2.5Y 6/4. Moist color is 10YR 4/3, 4/4, 5/4, 5/6 or 6/4. It is stratified sand, loamy sand, sandy loam or loam and is very gravelly, very cobbly, extremely gravelly or extremely cobbly. Clay content ranges from 5 to 15 percent. Gravel content ranges from 25 to 80 percent and cobble content ranges from 10 to 40 percent. Total coarse fragment content ranges from 35 to 90 percent. Base saturation ranges from 10 to 35 percent. Reaction is neutral through strongly acid.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Frenchman soils occur on stream terraces. They are 6 to 60 meters above present river levels and do not flood. Slopes are 0 to 9 percent. Elevations are 76 to 518 meters. These soils formed in alluvium derived from mixed sources. The climate is humid with cool foggy summers and cool moist winters. A moderate coastal fog influence limits the diurnal and annual ranges of temperature. Mean annual precipitation ranges from 1000 to 2030 millimeters. Mean January temperature is about 6 degrees C., mean July temperature is about 18 degrees C. and the mean annual temperature is about 12 degrees C. The frost-free period is 220 to 320 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gshwend, Kibesillah, Ornbaun, Yellowhound and Zeni soils on surrounding uplands. Gshwend soils are located on the same position and contain less than 35 percent coarse fragments in the control section. Ornbaun and Zeni soils have fine-loamy particle-size control sections. Yellowhound and Kibesillah soils occur on uplands, have argillic horizons, and are less than 150 centimeters deep to bedrock.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; runoff under bare soil conditions is low or medium; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: This soil is used for timber production, recreation, wildlife habitat and watershed. Vegetation consists of Douglas-fir, coast redwood, tanoak, and California huckleberry.

DISTRIBUTION AND EXTENT: Coastal Redwood Belt, MLRA 4B. This series is not extensive.

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

SERIES ESTABLISHED: Mendocino County, California, Eastern Part, 1985.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

1. Ochric epipedon -- the zone from 0 to 30 centimeters (O and A horizons).

2. Cambic horizon -- the zone from 30 to 81 centimeters (Bw1, Bw2 horizons).

3. Particle size control section - the zone from 25 to 200 centimeters averages 14.5 percent clay, by weight, 39 percent gravel, and 12 percent cobble, by volume (A, Bw1, Bw2, and 2C1 horizons).

4. Dystrustepts feature: base saturation is less than 60 percent by ammonium acetate in the depth between 25 and 75 centimeters from the mineral soil surface.

ADDITIONAL DATA: NASIS User Pedon ID: 06CA601601
Soil classified using Keys to Soil Taxonomy, 12th edition.

National Cooperative Soil Survey
U.S.A.