LOCATION PERRYGULCH CAEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, thermic Typic Endoaqualfs
TYPICAL PEDON: Perrygulch loam on a southeast facing slope of 3 percent under annual grasses and forbs at 230 feet elevation. (Colors are for dry soil unless otherwise stated. When described on September 26, 1985, the soil was moist below 16 inches).
A--0 to 3 inches; light brownish gray (2.5Y 6/2) loam, brown (10YR 4/3) moist; moderate fine and medium granular structure; soft, friable, slightly sticky and slightly plastic; many very fine roots; many very fine and fine interstitial pores; 5 percent hard angular pebbles (2-30mm); strongly acid (pH 5.4); clear wavy boundary. (2 to 8 inches thick)
Ag--3 to 7 inches; light gray (2.5Y 7/2) loam, grayish brown (2.5Y 5/2) moist; common fine distinct strong brown (7.5YR 5/6) redox concentrations, brown (7.5YR 4/4) moist; moderate medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular and interstitial and few fine tubular pores; 5 percent hard, angular pebbles (2-30mm); very strongly acid (pH 4.9); abrupt smooth boundary. (0 to 6 inches thick)
Btg1--7 to 16 inches; light gray (10YR 7/2) sandy clay loam, light brownish gray (10YR 6/2) moist; many fine distinct reddish yellow (7.5YR 6/6) redox concentrations, strong brown (7.5YR 5/6) moist; moderate fine medium and coarse subangular blocky structure; hard, firm, sticky and slightly plastic; few very fine roots; common very fine tubular and interstitial and common fine tubular pores; few thin clay films on peds and in pores; 5 percent hard, angular pebbles (2-30mm); very strongly acid (pH 4.7); abrupt smooth boundary. (6 to 12 inches thick)
Btg2--16 to 36 inches; light gray (2.5Y 7/2) clay, light brownish gray (2.5Y 6/2) moist; many fine and medium distinct very pale brown (10YR 7/4) redox concentrations, yellowish brown (10YR 5/6) moist; strong coarse and very coarse angular blocky structure; very hard, very firm, very sticky and plastic; few very fine roots; few very fine tubular and interstitial pores; many moderately thick and thick clay films on faces of peds and lining pores; 5 percent hard angular pebbles (2-30mm); very strongly acid (pH 5.0); gradual wavy boundary. (15 to 25 inches thick)
Bt1--36 to 44 inches; light gray (2.5Y 7/2) sandy clay, light yellowish brown (2.5Y 6/4) moist; many medium and coarse distinct strong brown (7.5YR 5/6) redox concentrations, strong brown (7.5YR 4/6) moist; weak medium and coarse subangular blocky structure; hard, firm, sticky and plastic; few very fine roots; few very fine tubular and interstitial pores; many thin clay films on faces of peds and lining pores; 5 percent hard angular pebbles (2-30mm); very strongly acid (pH 4.8); clear wavy boundary. (6 to 20 inches thick)
Bt2--44 to 52 inches; variegated light gray (2.5Y 7/2) and pale yellow (2.5Y 7/4) sandy clay loam, light yellowish brown (2.5Y 6/4) moist; common fine distinct strong brown (7.5YR 5/6) redox concentrations, strong brown (7.5YR 5/6) moist; weak fine and medium subangular blocky structure; hard, firm, sticky and plastic; few very fine roots; few very fine interstitial and common very fine tubular pores; common moderately thick clay films on faces of peds and lining pores; 5 percent hard angular pebbles (2-30mm); strongly acid (pH 5.4); clear wavy boundary. (0 to 10 inches thick)
2Bt3--52 to 61 inches; variegated pale yellow (2.5Y 7/4) and light yellowish brown (2.5Y 6/4) gravelly sandy clay loam, light yellowish brown (2.5Y 6/4) and light olive brown (2.5Y 5/4) moist; massive; slightly hard, friable, sticky and slightly plastic; few very fine roots; common very fine tubular and interstitial pores; few moderately thick clay films on fracture faces, lining pores and bridging sand grains; 30 percent hard, rounded, subangular and angular pebbles (2-50mm); 50 percent of horizon is very soft, highly weathered sandstone fragments (2-50mm); slightly acid (pH 6.2).
TYPE LOCATION: Mendocino County, California; about 2450 feet east and 1400 feet south of the northwest corner of sec. 11, T.14N., R.15W., MDBM, Boonville SW quadrangle.
RANGE IN CHARACTERISTICS: Thickness of the solum and depth to bedrock is greater than 60 inches. The mean annual soil temperature ranges from 59 to 62 degrees. The soil between the depths of 6 and 18 inches is dry in all parts from August 1 to October 1 and is moist in all parts from November 1 to June 15 in most years. The particle-size control section averages 35 to 45 percent clay.
The A horizon is 2.5Y 5/2, 6/2; 10YR 5/2, 5/3, 6/2 or 6/3. Moist color is 2.5Y 4/2, 5/2; 10YR 3/2, 3/3, 4/2 or 4/3. Clay content ranges from 15 to 27 percent. Organic carbon content ranges from 0.6 to 3.0 percent. Gravel content ranges from 2 to 10 percent. Soil reaction is very strongly to medium acid.
The Bt horizon is 2.5Y 5/4, 6/4, 7/2, 7/4; 10YR 5/2, 6/2, 6/3 or 7/3. Moist colors are 2.5Y 5/4, 6/2, 6/4; 10YR 4/2, 5/3, 5/4 or 6/3. Mottle colors are 10YR 5/8, 6/1, 7/1, 7/4; 7.5YR 5/6, 5/8 or 6/6. Moist mottle colors are 10YR 5/1, 5/6, 5/8, 6/1, 6/8; 7.5YR 4/6, 5/6 or 5/8. Matrix or mottle colors with moist chromas of 1 or 2 are redox depletions and occur between the surface and a depth of 10 inches and may continue to greater than 60 inches. Mottle colors with chroma of 6 and 8 are redox concentrations. The Bt horizon is sandy clay loam, clay loam, sandy clay, or clay. Gravelly or very gravelly sandy clay loams occur below 50 inches in most, but not all, pedons. Clay content ranges from 25 to 50 percent. Hard gravel content is typically 2 to 10 percent but ranges from 25 to 50 percent in the gravelly or very gravelly subhorizon. Base saturation (sum) ranges from 40 to 75 percent in the upper part and 50 to 90 percent in the lower part. Reaction is very strongly through slightly acid
COMPETING SERIES: This is the Argent (SC) series. The Argent soils have a water table at or near the surface for 2 to 6 months and rainfall is evenly distributed throughout the year.
GEOGRAPHIC SETTING: The Perrygulch soils occur on river terraces. Slopes are 0 to 9 percent. Elevations are 150 to 400 feet. The soils formed in alluvium derived from mixed rock sources, mainly sedimentary. The climate is characterized by hot dry summers and cool moist winters. Mean annual precipitation varies from 40 to 50 inches. The mean January temperature is about 44 degrees F., the mean July temperature is about 72 degrees F., and the mean annual temperature is 54 to 58 degrees F. The frost-free season is 175 to 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Boonville, Cole, Feliz, Pinole and Talmage soils. Boonville soils are fine-loamy and somewhat poorly drained. Cole soils are somewhat poorly drained. Feliz and Pinole soils are fine-loamy and well drained. Talmage soils are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Very poorly drained. These soils are saturated with water for extended periods following episodes of heavy rain from December through April. The saturated zone starts between the surface and a depth of 10 inches and extends to greater than 60 inches. The soil is not saturated above 60 inches from summer through early fall. Surface runoff under bare soil conditions is very slow through medium. Permeability is slow.
USE AND VEGETATION: This soil is used as rangeland. Vegetation consists of annual grasses and forbs.
DISTRIBUTION AND EXTENT: Anderson Valley, California. The series is not extensive. MLRA 14.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Mendocino County, California, Western Part, 1993.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon -- 0 to 7 inches (A, Bg)
Argillic horizon -- 7 to 61 inches (Btgl, Btg2, Bt1, Bt2, 2Bt3)
Base saturation -- 40 to 75 percent in some part of the upper 30 inches of the argillic horizon. 50 to 90 percent 50 inches below the top of the argillic horizon.
Particle-size family -- fine. Weighted average clay content in control section (7 to 27 inches) is 41 percent.
The classification was changed in 1993 from Aquultic Haploxeralfs to Typic Endoaqualfs.
The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET