LOCATION RICHARDSON              AK

Established Series
Rev. SR/DLM
02/2022

RICHARDSON SERIES

Depth class: very deep
Drainage class: moderately well drained
Parent material: loess over alluvium
Landform: stream terraces and escarpments on stream terraces
Slopes: 0 to 50 percent
Mean annual precipitation: about 13 inches, 330 mm
Mean annual temperature: about 27 degrees F., -2.8 C.

TAXONOMIC CLASS: Coarse-silty, mixed, superactive Aquic Haplocryepts

TYPICAL PEDON: Richardson silt loam - on a slope of 1 percent under paper birch and black spruce at 880 feet elevation. (All colors are for moist soil unless noted)

Oe--0 inches to 2, (0 to 5 cm); very dark brown (10YR 2/2) moderately decomposed plant material; many roots; extremely acid (pH 4.0); abrupt smooth boundary. (1 to 4 inches thick)

A--2 to 4 inches, (5 to 10 cm); mixed black (N 2/) and dark brown (10YR 3/3) silt loam; weak very fine granular structure; many roots; many charcoal fragments; very strongly acid (pH 5.3); abrupt irregular boundary. (0 to 5 inches thick)

AB--4 to 7 inches, (10 to 18 cm); dark grayish brown (2.5Y 4/2) silt loam; weak very thin platy structure; very friable; common roots; streaks and patches of very dark grayish brown (10YR 3/2) and black (N 2/); strongly acid (pH 5.3); abrupt wavy boundary. (0 to 7 inches thick)

Bg--7 to 18 inches, (18 to 46 cm); olive (5Y 4/3) silt loam; weak very thin platy structure; very friable; common roots; common medium distinct dark brown (10YR 3/3) redoximorphic features; slightly acid (pH 6.2); gradual boundary. 7 to 25 inches thick

C1--18 to 29 inches, (46 to 74 cm); olive gray (5Y 5/2) silt; very friable; few roots; many medium prominent olive brown (2.5Y 4/4) redoximorphic features; neutral (pH 6.7); gradual boundary. (10 to 20 inches thick)

C2--29 to 53 inches, (74 to 135 cm); gray (5Y 5/1) silt; weak very thin platy structure; very friable; common coarse prominent dark yellowish brown (10YR 4/4) redoximorphic features; neutral (pH 6.8); abrupt smooth boundary. 15 to 25 inches thick)

2C3--53 to 60 inches, (123 to 152cm); gray (5Y 5/1) fine sand; single grained; neutral (pH 6.7).

TYPE LOCATION: Totchaket Area, Alaska; in the NE 1/4 of the NE 1/4, section 9, T. 4 S., R. 9 W; Fairbanks Meridian.

RANGE IN CHARACTERISTICS:
Particle-size control (section weighted average): less than 15 percent sands coarser than very fine sand and 5 to 10 percent clay
Soil moisture regime: udic
Mean annual soil temperature: about 32 degrees F., 0 C.
Thickness of loess mantle: 40 to 60 inches, 102 to 152 cm

O horizon:
Matrix color: hue of 7.5YR to 10YR; value of 2 or 3; chroma of 1 or 2
Texture: slightly or moderately decomposed plant material
Reaction: extremely acid to strongly acid

A horizon:
Matrix color: hue of 7.5YR to N; value of 2 to 4; chroma of 1 to 3
Texture: silt loam or mucky silt loam
Reaction: strongly acid to slightly acid

B horizons:
Color: hue of 10YR to 5Y; value of 3 to 5, chroma of 2 to 4
Texture: silt loam, very fine sandy loam, sandy loam, or stratified silt loam and very fine sandy loam
Reaction: moderately acid to slightly acid

BC or C horizons:
Matrix color: hue of 10YR to 5Y; value of 3 to 6, chroma of 2 to 4
Texture: silt loam, very sandy loam, sandy loam, or stratified silt loam to sandy loam modified by 0 to 25 percent total coarse fragments, 0 to 25 percent gravel, 0 to 5 percent cobbles
Reaction: moderately acid to neutral

2C horizon:
Matrix color: hue of 2.5Y or 5Y; value of 3 to 5; and value of 1 to 4.
Texture: sand, coarse sand, or loamy sand modified by 0 to 65 percent total coarse fragments, 0 to 65 percent gravel, 0 to 10 percent cobbles
Reaction: moderately acid to neutral

COMPETING SERIES: These are the Kenspur and Minto series. Kenspur series are slightly calcareous. Minto soils lack coarse fragments.

GEOGRAPHIC SETTING:
Parent material: loess over alluvium
Landform: stream terraces, escarpments on stream terraces
Slope: 0 to 50 percent
Mean annual temperature: 24 to 34 degrees F., -4.4 to 1.1 C.
Mean annual precipitation: 10 to 15 inches, 254 to 381 mm

GEOGRAPHICALLY ASSOCIATED SOILS: These include the list soil series. Volkmar soils occur on terraces and are moderately well drained. Tetlin soils are on bedrock cored hills and are poorly drained.

DRAINAGE AND PERMEABILITY: Moderately well drained, low to high runoff, saturated hydraulic conductivity is moderately high in the solum and very high in the substratum.

USE AND VEGETATION: Used for wildlife habitat, woodland, and small grains, grasses, and vegetables. The native vegetation includes black spruce, white spruce, and paper birch.

DISTRIBUTION AND EXTENT: MLRA 229, Interior Alaska Lowlands, The series is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA

SERIES ESTABLISHED: Salcha-Big Delta Area, Alaska, 1967.

REMARKS: Diagnostic features and horizons recognized in this profile include:
Cambic horizon of feature: from 7 to 18 inches, 18 to 46 cm
Particle size control section: coarse-silty from 12 to 42 inches from top of soil surface
Temperature regime: Cryic
Moisture regime: Udic
Under a thick O horizon, a subsurface layer in these soils may remain frozen throughout the summer, indicating a mean annual soil temperature of 0 degrees C. or less in those soils. Investigation to determine the prevailing temperature regime in Richardson soils is needed for accurate classification (SR, 5/78).

In the spring water is perched on seasonal frost.

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National Cooperative Soil Survey
U.S.A.